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ENGLISH PHILOSOPHERS 
 
 Sir William Hamilton 
 
 W. H. S. MONCK, M.A. 
 
 PROFESSOR OF MORAL PHILOSOPHY IN THE UNIVERSITY OF DUBLIN 
 
 NEW YORK 
 P. PUTNAM'S SONS 
 27 AND '29 W. 23D Street 
 
 I 88 I 
 
44^-o-e^^-+. 
 
 UNiVEHSITY: 
 
 /y")/^' 
 
 \. 
 
 LIBRARY 
 
SIR WILLIAM HAMILTON. 
 
 PEEFACE 
 
 THE EDITOR. 
 
 The appearance or the first instalment of the Series of 
 English Philosophers affords the Editor an opportunity of 
 defining the position and aim of this and the succeeding 
 volumes We live in an age of series ; Art, Science, 
 Letters, are each represented by one or more ; it is the 
 object of the present Series to add Philosophy to the list of 
 subjects which are daily becoming more and more popular. 
 Had it been our aim to produce a History of Philosophy in 
 the interests of any one school of thought, co-operation would 
 have been well-nigh impracticable. Such, however, is not 
 our object. We seek to lay before the reader what each 
 English Philosopher thought and wrote about the problems 
 with which he dealt, not what we may think he ought to 
 liave thought and written. Criticism will be suggested 
 rather than indulged in, and these volumes will be exposi- 
 tions rather thati reviews. The size and number of the 
 volumes compiled by each leading Philosopher are chiefly due 
 to the necessity, whicli Philosophers have generally ecu- 
 
PREFACE. 
 
 sidered imperative, of demolishing all previous systems of 
 Philosophy before they commence the work of constructing 
 their own. Of this work of destruction little will be found 
 in these volumes; we propose to lay stress on what a Philo- 
 sopher did rather than on what he undid. In the summary 
 will be found a general survey of the main criticisms that 
 have been passed upon the views of the Philosopher who 
 forms the subject of the work, and in the bibliographic 
 appendix the reader will be directed to sources of more 
 detailed criticism than the size and nature of the volumes in 
 the Series would permit. The lives of Philosophers are not, 
 as a rule, eventful, the biographies will consequently be 
 brief. It is hoped that the Series, when complete, will 
 supply a comprehensive History of English Philosophy. It 
 will include an Introduction to the Study of Philosophy, by 
 Professor H. Sidgwick. 
 
 OXFOED, Nov., 1880, 
 
CONTENTS. 
 
 CHAPTER I. 
 
 PASS 
 
 BlOGEAPHICAL AND InTKODUCTOE'V 1 
 
 CHAPTER II. 
 The External Wohld — Natfeal Realism . . . .16 
 
 CHAPTER III. 
 Necessaet TEfTHs — The Law of the Conditioned . . 4,8 
 
 CHAPTER IV. 
 The Law of Causation 61 
 
 CHAPTER V. 
 
 The Infinite and Absolute — The Law of Substance . . 81 
 
 CHAPTER VI. 
 The Geneeal Psychology of Hamilton 102 
 
 CHAPTER VII. 
 Logic .... ....... 141 
 
 APPENDIX. 
 Hamiltonian Litebatuee 165 
 
 Glossaey of Philosophical Teems ....»• J68 
 
Cornell University 
 Library 
 
 The original of tiiis book is in 
 tine Cornell University Library. 
 
 There are no known copyright restrictions in 
 the United States on the use of the text. 
 
 http://www.archive.org/details/cu31924029012239 
 
SIE WILLIAM HAMILTON. 
 
 CHAPTER I. 
 
 BIOGEAPHICAL AND INTRODUCTORY. 
 
 Sir William Hamilton was born at Glasgow in the year 
 1788. His birth took place in the College where his 
 father, Dr. William HamiltoHj filled the chair of Anatomy 
 and Botany, which had formerly been occupied by his 
 grandfather, Dr. Thomas Hamilton. He received the names 
 of William Stirling, the latter being his mother^'s family 
 name ; but he dropped the Stirling soon after coming ot 
 age, and it .-ippears for the last time when he passed his 
 final ezamination at Oxford in 1810. He was only two years 
 old when his father died at the early age of thirty-two, 
 leaving his widow and two children — the future philosopher, 
 and a younger brother named Thomas, who afterwards entered 
 the army and attained some distinction in the department of 
 literature. Dr. Hamilton appears to have left his family 
 sufficiently (though probably not handsomely) provided for, 
 and Sir William and his brother received an excellent 
 education. He succeeded to the family baronetcy in 1799, 
 but no estate accompanied the title, his right to which was 
 only proved (with considerable trouble and expense) thirteen 
 or fourteen years later ; so that during his school and college 
 days he was known as plain William Hamilton. He con- 
 
 B 
 
S/R WILLIAM HAMILTON. 
 
 tinued to reside in Glasgow after liis father's death until the 
 year 1801, when he was sent to school in England, having 
 previously it seems attended the Junior Greek and Latin 
 classes of the University at the age of twelve. The figure of 
 the venerable Reid, whose works he was destined to edit long 
 afterwards, was no doubt familiar to him during early child- 
 hood, but the philosophy of Reid and Stewart appears to have 
 been little studied at Glasgow until after he left that 
 University. Notwithstanding his attendance at the classes 
 mentioned, he does not appear to have entered the University 
 of Glasgow until after his return from England in 1803. He 
 then distinguished himself in the department of Logic and 
 Moral Philosophy, and it is worth noticing that Reid's 
 successor — Professor Mylne — under whom he studied, was a 
 Sensationalist in Psychology and an Utilitarian in Ethics. 
 Hamilton's subsequent hostility to these theories cannot 
 therefore be ascribed to early training, and judging from the 
 fact that he records the purchase of Reid's works in one of 
 his letters while at Oxford, it would appear that he was not 
 previously acquainted with that author. Being intended for the 
 medical profession like his father and grandfather, his studies 
 were naturally directed to that object, and in particular he 
 devoted a good deal of time to Chemistry, the only physical 
 science (except Physiology) with which he seems to have had 
 much acquaintance, and which undoubtedly coloured (among 
 other things) his theory of causation. After going to Edin- 
 burgh to pursue his medical studies, his mother decided to 
 send him to Oxford, and he entered that University as a 
 student of Balliol College in 1807. He obtained a Snell 
 Exhibition — a prize instituted by a Scotchman for the pur- 
 pose of assisting deserving youths of his own country to take 
 Degrees at the leading English University — and by refraining 
 from any considerable expenditure, except on books, his 
 
BIOGRAPHICAL AND INTRODUCTORY. 3 
 
 University career did not prove an expensive one. He does 
 not seem to have become acquainted with many of the Oxford 
 students (then unusually numerous) who made names for them- 
 selves in after-life, and excejit his countryman Lockhart, the 
 names of his associates mentioned by his biographer call for 
 no remark. As in one of his letters, however, he takes up the 
 cause of Mr. Copleston rather warmly in his controversy with 
 the Edinburgh Review, we may perhaps assume that he came 
 to a certain extent under the influence of the man to whom the 
 revival of Logic as a study at Oxford has chiefly been ascribed. 
 He was undoubtedly a hard reader, and the number of books 
 which he took up for his final examination in Literis Humani- 
 ■oribus was regarded as unprecedented. They were mainly 
 philosophical, and included almost all the writings of Aristotle, 
 together with the philosophical works of Cicero ; but his 
 books were certainly more numerous than his authors. His 
 name appears in the First Class : but as the names in that 
 class are printed alphabetically and not in order of merit, 
 we are unable to ascertain the precise position which he 
 occupied as regards his contemporaries, none of whom sub- 
 sequently attained any remarkable distinction. He was not 
 elected to a Fellowship at Balliol College, but that may have 
 been owing to the disfavour with which Scotchmen were re- 
 garded at the time. He evidently acquired a high reputation 
 at Oxford as a student of philosophy, but his attainments in 
 that department were only tested indirectly by means of an 
 examination in Greek and Latin philosophical works — the 
 former limited to Aristotle and the latter to Cicero. 
 
 Leaving Oxford in 1811 (except for occasional visits) Sir 
 William Hamilton changed his intended profession, and be- 
 came an Advocate in the year 1813. His success at the 
 Scottish bar was not brilliant, but there seems uo reason to 
 doubt that if he had devoted his attention to his profession 
 
 B 2 
 
SIR WILLIAM HAMILTON. 
 
 he would have earned a respectable livelihood. Reading, 
 however, seems to have been his chief oecupatioUj and in this 
 respect the Advocates' Library had great attractions for him. 
 He had become a book collector at a very early age, and his 
 private library was already attaining considerable dimensions. 
 In 1820 the Professorship of Moral Philosophy in the Uni- 
 versity of Edinburgh became vacant by the death of Dr. 
 Brown, who had latterly been the colleague of Stewart. 
 Hamilton does not appear to have been acquainted with 
 Brown, though he had resided in Edinburgh since his call to 
 the bar, and it seems to have been on the occasion of his 
 present candidature that he first met Stewart. The appoint- 
 ment rested with the Town Council of Edinburgh. Mr. 
 MacVey Napier, afterwards editor of the Edinhnrgh Review, 
 was at first a caTididate with the support of Stewart, but does 
 not seem to have persevered in his canvass: and the contest 
 lay between Hamilton and John Wilson, better known in the 
 literary world as Christopher North. Hamilton was a Whig, 
 and Wilson was a Tory ; and as the latter party preponderated 
 in the Town Council, Wilson proved the successful com- 
 petitor. That the world would have gained much by the 
 election of Hamilton cannot be doubted, but I think the 
 Town Council has been unduly censured for its choice. 
 Hamilton had hitherto published nothing. His prize at 
 Glasgow sixteen years before had been awarded by his fellow- 
 students to a boy in his teens, while his Oxford distinction 
 had been mainly won by his classical knowledge. He had 
 been for several years a practising Advocate, and there was 
 nothing to show (so far as I am aware) that during that 
 period he had been an active student of philosophy. Wilson's 
 philosophical credentials were probably not of a high order, 
 but he was a man of undoubted ability. The selection was 
 certainly not the worst instance of party-spirit that has 
 
BIOGRAPHICAL AND INTRODUCTORY. 5 
 
 occurred with respect to such appointments, nor perhaps are 
 they much purer in the hands of the Government than of a 
 Town Council. Hamilton and Wilson were friends, and the 
 incident did not interrupt their friendship ; while many years 
 afterwards Sir William took an opportunity of making a com- 
 plimentary allusion to Wilson in his own Lectures.' 
 
 Soon after this, Hamilton was appointed to the chair of 
 History in the University of Edinhurgh, the emoluments of 
 which post only amounted to 100/. a year, and he also received 
 a small law appointment as Solicitor of Teinds. He appears 
 to have abandoned his practice at the bar and lived with his 
 mother and his cousin. Miss Marshall, reading and making addi- 
 tions to his library, and occasionally astonishing casual visitors 
 by the extent of his erudition. Phrenology had at this period 
 become fashionable in Edinburgh under the auspices of Mr. 
 George Combe. Hamilton made a great number of researches 
 on the skulls of men and other animals (including some expe- 
 riments on live animals) with the view of testing its pretensions, 
 and afterwards published the result of his inquiries, which 
 were decidedly adverse to the theories of Gall and Spurzheim. 
 A summary of these researches appears in an appendix to the 
 first volume of his Lectures, and if we may judge by them 
 Hamilton would have proved a successful student of Physio- 
 logy had he been able to devote more time to that science. 
 He retained his interest in it undiminished up to the last ; 
 and while his investigations possess the interest of being his 
 earliest publication, I am not aware that his results have ever 
 been displaced. 
 
 During the period subsequent to 1820, Hamilton seems to have 
 become better acquainted with Stewart, and in a letter of the lat- 
 ter which is extant he acknowledges his indebtedness to Hamil- 
 
 ' Lect. ii. p. 382. This passage, if not this whole Lecture, must have 
 been written as late as 1854. 
 
SIR WILLIAM HAMILTON. 
 
 ton for " much curious and valuable information about the later 
 philosophers of Germany, whose merits and defects he seems 
 to me to have appreciated with great candour and discrimina- 
 tion. -"^ If, however, this " curious and valuable information ■" 
 was that which Stewart published a few years afterwards in his 
 Dissertation on the Progress of Philosophy, the incident 
 does not redound very much to Hamilton's credit. Stewart, 
 however, in the course of that Dissei tation, only refers to him 
 on one occasion when alluding to Eschenbach, who unmis- 
 takably anticipated Sir William Hamilton's subsequent doc- 
 trine of Natural Realism, though Hamilton himself ascribes it 
 to no modern philosopher except Poiret and Reid (with the 
 possible addition of Sergeant).' Tliis doctrine evidently 
 puzzled Stewart, who could not make up his mind as to whether 
 Eschenbach was " right or wrong." I may here remark that 
 Professor Veitch, in his Memoir, tells us that it appears from 
 Hamilton's Common Place Book, that he had adopted the 
 doctrine of Natural Realism, in all its essentials, as early as 
 1823, and therefore previous to the publication of Stewart'.s 
 Dissertation ; but Stewart refers to him merely as the source 
 of a curious piece of literary information and not as an autho- 
 rity on philosophy. 
 
 Sir William Hamilton's mother died in the year 1827, and 
 two years later the future philosopher married Miss Marshall, 
 the cousin who had resided with him and his mother for several 
 years before her death. The union proved a happy one, though 
 many ladies would have objected to the continual work as her 
 husband's amanuensis, which Lady Hamilton cheerfully under- 
 went. That she had much to do with his subsequent distinc- 
 tions seems to be admitted, and I suspect it was in no small 
 degree owing to her influence that the recluse student became 
 an author for substantially the first time, six months after his 
 ' Stewart's Works, i. pp. 584-6. Hamilton's Edition. 
 
BIOGRAPHICAL AND INTRODUCTORY. 7 
 
 marriage, and when he had passed his fortieth year. The 
 immediate cause of his coming before the public, however, was 
 the appointment of his friend, Mr. MacVey Napier, as editor 
 of the Edinburgh Review in succession to Lord Jeffrey, in 
 1829. Napier insisted on Hamilton's supplying an article 
 for the first number of the Review which came out under his 
 auspices, and the result was his famous Discussion on the Un- 
 conditioned, which revealed to Continental thinkers the unsus- 
 pected existence in this country of a great philosopher, who 
 could look beyond the narrow confines of Great Britain. M. 
 Cousin, against whom the article was chiefly directed, con- 
 ceived the warmest feelings of admiration and respect for its 
 author, with whom he soon after entered into correspondence, 
 and in whose behalf he exerted himself to the utmost when the 
 Chair of Logic in the University of Edinburgh became vacant. 
 The friendship of the two philosophers, indeed, lasted up to 
 Hamilton's death. This Discussion was followed by another 
 on the Theory of Perception in 1830, and a third on Logic in 
 1833; and Hamilton likewise contributed a large number of 
 articles on other subjects to the Edinburgh Review from 1829 
 to 1836, in which he showed himself particularly zealous in 
 the cause of University Reform, and the admission of Dissen- 
 ters to the Universities. It may here be remarked that 
 Hamilton was an attached member of the Church of Scotland, 
 in whose subsequent troubles he took much interest, and was 
 always a sincere and consistent believer in Christianity. In 
 politics he was a Liberal, and he adhered to his political views 
 with such firmness as to estrange some of the most intimate 
 of his early friends — for instance Lockhart. With Wilson, 
 however, he always continued on good terms, although they 
 were rival candidates for a chair of philosophy, which seems 
 to have been in a great measure disposed of on political 
 grounds. 
 
S/R WILLIAM HAMILTON. 
 
 Hamilton had completed his forty-eighth year before his 
 appointment to a chair of philosophy, and even then three or 
 four articles in the Edinhurgh Review were the only contribu- 
 tions to that science to which he could point as credentials. 
 ilow much more he might have accomplished if he had 
 received the appointment earlier, it is vain to speculate; but 
 it is perhaps the prevailing fault of all Academical patrons to 
 select a middle-aged or elderly man who has already made a 
 reputation, rather than a young man who gives every indi- 
 cation that he is prepared to make one whenever an opening 
 presents itself. We cannot regret that such a choice was 
 ultimately made in Hamilton''s case ; but the result was that 
 the real scope of his philosophical activity was limited to a 
 period of eight years, and after that period the paralytic man, 
 who tottered down to read the lectures which he had written 
 years before, would, if those eight years had proved less 
 fruitful, have almost afforded a caution against such appoint- 
 ments for the future. Dr. Ritchie resigned the chair of Logic 
 in the University of Edinburgh in I806. Hamilton's prin- 
 cipal opponent was Mr. Isaac Taylor of Ongar, who, like 
 Wilson, had displayed great ability in other departments, but 
 had no special qualifications for the vacant professorship. 
 Hamilton was elected by eighteen votes to fourteen ; but he 
 received the chair, which was not a very valuable one, subject 
 to the condition of paying Dr. Ritchie 100/. a year for the 
 rest of his life — a serious deduction to one whose family was 
 rapidly increasing. During the first session Hamilton wrote 
 his Lectures on Metaphysics almost in the form in which 
 they were published after his death. He had contracted that 
 habit of procrastination which often accompanies the con- 
 sciousness of unusual power, and many of these lectures only 
 received the author's final corrections and alterations imme- 
 diately before they were delivered. He often sat up almost 
 
BIOGRAPHICAL AND INTRODUCTORY. 9 
 
 the whole of the preceding night, husied in preparation, Lady 
 Hamilton sitting up with him, and acting as his amanuensis. 
 Written under such circumstanc(5s, the Lectures can hardly 
 be regarded as finished expositions of his philosophical views ; 
 yet, from the fact that they were delivered almost unaltered 
 for nearly twenty years, we may conclude that they contain 
 a reliable statement of the substance of the Hamiltonian 
 doctrine. The Lectures on Logic were composed during the 
 next session. The author considered them much more 
 finished, as well as more valuable than those on Metaphysics, 
 but posterity will, I think, reverse the verdict. They were 
 in many instances prepared under the same pressure as their 
 predecessors, and translations from Krug and Esser were 
 often used to supply the unfinished portions of the author's ' 
 sketches. He seems to have become aware at an early period 
 that anything more recondite than these lectures would not 
 be intelligible to his audience, and consequently to have re- 
 solved on bringing a detailed exposition of his system before 
 the public in a different form. For this purpose he chose an 
 edition of the works of Reid — a philosopher to whom, on the 
 whole, he paid more deference than any other, with the pos- 
 sible exception of Aristotle. The selection of such a form of 
 exposition was unfortunate, and circumstances aggravated the 
 evil. First, he quarrelled with his intended publisher, and 
 not having selected another, he got the work stereotyped as 
 far as it had then been printed — thus precluding all correc- 
 tion, or reconciliation of his earlier and later views. Then 
 followed a quarrel with the Town Council of Edinburgh about 
 his lectures, which occupied much of his time, and prevented 
 him from delivering a second and more advanced course of 
 lectures. Then came the death of his brother, to whom he 
 was greatly attached, and the threatened disruption of the 
 Scottish Church, which he laboured hard to avert; and, 
 
I o SIR WILL I A M HA MIL TON. 
 
 iinally, when the work was still incomplete, a paralytic stroke 
 almost deprived him of the use of his right side for the rest 
 of his life. This calamity overtook him i-n the year 1844. 
 
 Hamilton's mental faculties were still unimpaired, but he 
 evidently lacked his former energy after his partial recovery, 
 and, moreover, we hear of repeated illnesses from this period 
 until his death, whereas he had formerly been remarkable for 
 strength and activity, as well as for general good health. In 
 1846 he published his unfinished edition of the works of Reid, 
 one of his supplementary dissertations breaking off in the 
 middle of a sentence. It was never completed; and the 
 materials which his editors collected and published after his 
 death probably form but a small portion of what before his 
 illness he intended to add. The work, however, even as it 
 stands, is one of marvellous labour and research, and though 
 not always containing the author's latest views, is that to 
 which his disciples usually refer as the best exposition of his 
 system. All idea of revising or altering his lectures, except 
 by occasional oral interpolations, was now abandoned, and 
 neither of the works which he announced as preparing for 
 publication at the end of this edition of Reid ever appeared. 
 How much of what he subsequently published was written 
 before 1844, it is difficult to ascertain; but his later publica- 
 tions, in any event, were not extensive. In 1852 he repub- 
 lished his Discussions from the Edinburgh Review, with 
 additions and alterations, and shortly before his death he 
 published an edition of the works of Stewart, in brincrino- out 
 which, however, he confined himself to the task of an editor, 
 and added very few philosophical annotations. He still 
 lectured to full classes, using his old lectures, and the effijrt 
 of delivery having become painful, these were not unfrequently 
 read by an assistant. He died very shortly after the close of 
 the Academical Session of 1856, after a brief illness ; but his 
 
BIOGRAPHICAL AND INTRODUCTORY, ii 
 
 health appears to have heen continually becoming worse since 
 his terrible attack in 1844. Latterly he enjoyed a small pen- 
 sion from the Civil List ; but he was never in affluent circum- 
 stances, and it required great care on the part of himself and 
 Lady Hamilton to bring up his family respectably, while 
 making the additions to his library, which formed almost his 
 sole personal expenditure. His eldest son entered the army 
 some years before his death, and the philosopher seems to 
 have watched over him with almost more than parental 
 solicitude. 
 
 Hamilton was much loved by his pupils, and to all who 
 came to him for information he was kind and condescend- 
 ing. His temper, however, was imperious. He was impa- 
 tient of opposition, and being an ardent reformer, was pretty 
 often opposed; but he was more frequently engaged in a 
 quarrel with some public body than with private indivi- 
 duals. He had all the waywardness of genius, and such were 
 his eccentricities in connexion with his famous articles in the 
 Edinburgh Review, that his connexion with that periodical 
 would probably have terminated even independently of his 
 appointment to the chair of Logic. He would at the last 
 moment send in an article far exceeding the limits agreed 
 upon, thus compelling the editor to exclude something else to 
 make room for it, while from the time of its arrival it was 
 impossible to modify its language where the editor deemed it 
 too strong. Afterwards, under the pressure of his infirmity 
 (which he otherwise bore with great fortitude), his temper 
 seems to have become more acrimonious, and those who 
 ventured to enter into controversy with him had no pleasant 
 time of it. He was, however, always a strictly honourable, 
 and sometimes even a generous opponent, and he enjoyed the 
 respect and esteem not only of his friends, but of the public 
 np to the last ; and if 
 
12 SIR WILLIAM HAMILTON. 
 
 " He can't be wrong whose life is in the right," 
 we have a strong testimony to the correctness of the Hamil- 
 tonian theory. 
 
 Something has been already said of the extent of Hamil- 
 ton's reading. He was from his early years an ardent student 
 of classical literature, and his subsequent speculations were no 
 doubt largely influenced by this fact, and by his having been 
 sent to comiDlete his education at the University of Oxford, 
 where the writings of Aristotle were then held in high 
 esteem. Hamilton's studies, however, soon extended far 
 beyond the limits of the Oxford curriculum. Not content 
 with the works of the ancient Greek and Roman philo- 
 sophers, he turned with avidity to those of the Schoolmen, 
 and thence to those of the modern Continental philosophers. 
 The Scottish School had hitherto attached too little impor- 
 tance to the writings of its predecessors and foreign contem- 
 poraries. Hamilton undoubtedly went into the opposite 
 extreme. lu turning over his pages we might frequently 
 imagine that we were reading some curious volume of anti- 
 -quariau research, rather than a treatise on a science by a 
 professed expositor. His philosophical erudition has probably 
 never been equalled, but it was far too vast to be accurate. It 
 would be difficult to name a philosophical author whose system 
 he had thoroughly mastered, with two exceptions — Aristotle 
 and Reid. If he erred in any respect in his exposition of these 
 writers, it was not from want of acquaintance with their 
 works, but from his desire to assimilate their systems to his 
 own. But even as regards Stewart, I think he cannot always 
 be acquitted of errors of another kind. 
 
 His great erudition had another ill effect. When about to 
 write on any subject, he consulted so many authors, and made 
 •60 many extracts, that the work soon extended beyond all 
 reasonable dimensions, and unless compelled by the pressure 
 
BIOGRAPHICAL AND INTRODUCTORY. 13 
 
 of necessity (as in the ease of his lectures) to give the results 
 to the world, he ultimately became disheartened, and aban- 
 doned the effort in despair. There can be no doubt that if he 
 had read less he would have produced more, and with his 
 powerful intellect I doubt if his productions would even have 
 beea deteriorated in quality. I venture to suggest one more 
 bad consequence arising from the peculiar bent of his studies. 
 His wonderful acquaintance with Formal Logic led him almost 
 invariably to seek for some logical fallacy in an opponent's 
 argument, and when he hit upon a careless expression (arising, 
 perhaps, from a studied disregard of the technicalities of 
 Logic), he imagined he had found it, whereas a more careful 
 examination would have shown him that all appearance of 
 logical irregularity could have been got rid of while leaving 
 the argument intact. The truth is that investigators very 
 seldom really fall into any logical fallacy, though disputants 
 often do so. 
 
 Hamilton's latest philosophical writings published in his 
 life-time are to be found in the Appendices to the last edition 
 of his Discussions. After his death his editors published all 
 the materials for his edition of Reid which they could collect, 
 and also his Lectures ; and some of his very latest contribu- 
 tions to philosophy — found on his desk after his death — are 
 printed as Appendices to the latter. The Lectures are the 
 only part of his works that can be regarded as in any sense 
 complete, and even they obviously fall short of his original 
 design — partly owing, no doubt, to his quarrel with the 
 Town Council. Most of his logical theories, too, occurred to 
 him after the Lectures on Logic were written. He has left 
 no systematic exposition of his philosophy, and his readers 
 must be satisfied to make the most of the materials he has 
 left. But the imperfect is often more suggestive than the 
 complete, and the real student of philosophy will not, perhaps. 
 
14 S/R WILLIAM HAMILTON. 
 
 regard the state ia which Hamilton's works have come down 
 to us with unmingled regret. 
 
 The fundamental principles of the Hamiltonian Philosophy 
 may, I think, be thus enumerated: — 1st, His theory of Ex- 
 ternal Perception, or Natural Realism ; 2nd, His doctrine of 
 Native, Necessary or a priori Truths, and the tests by which 
 they can be discovered; 3rd, His law of the Conditioned, 
 including its application to the Principle of Causality; and, 
 4th, His consequent views concerning the impossibility of 
 knowing the Absolute and the Infinite. I do not include 
 his doctrine of the Relativity of Human Knowledge,' of 
 which so much has been said. So much of that doctrine 
 as is relevant and characteristic of Hamilton falls, in my 
 opinion, under the remaining heads, as is also the case with 
 his polemic against the Association Psychology. 
 
 ' But surely it is competent to a philosopher to maintain the relativity 
 of our knowledge of the external world without limiting himself to the 
 " one special relation " of cause and effect which Mr. Mill insists on. 
 
CPIAPTER II. 
 
 THE EXTERNAL WORLD — NATURAL REALISM. 
 
 It is perhaps by his solution of the problem of the existence 
 •of Matter — by his Natural Realism — that Sir William 
 Hamilton is best known. The question had long previously 
 attracted the attention of Philosophers. 
 
 All men naturally believe in an external world ; but when 
 the reasons of this belief came to be inquired into, the answers 
 given have often been very unsatisfactory. All men, it has 
 been alleged, naturally believed that the sun, moon, and stars, 
 went round the earth every twenty-four hours; but when the 
 grounds of this belief came to be examined, it was found to be 
 an illusion arising from the rotation of the earth upon its own 
 axis. Many philosophers arrived at the conclusion that the 
 belief in an external world is a similar illusion. Nothing 
 existed, they said, but minds and their various states of 
 feeling. Sensations and other feelings succeeded each other 
 according to certain laws, but these laws did not imply the 
 existence of anything but minds, and we had no reason to 
 believe that anything else existed. The best known advocate 
 of this doctrine in modern times was Berkeley, and his 
 denial of the external world was the source of almost all 
 modern speculation on the subject. Hume carried Berkeley's 
 theory farther, and applied it to subvert the substantial 
 reality of Mind as well of Matter. Reid, startled by the 
 
i6 SIR WILLIAM HAMILTON. 
 
 deductions of Hume, abanddied the doctrine of Berlceley 
 which he had at one time accepted, and argued strenuously in 
 favour of an external world. He was followed by Stewart, 
 but vigorously assailed by Brown, who, however, continued to 
 declare his belief in an external world, while rejecting almost 
 all his master's arguments in its favour. Meanwhile Hume 
 had roused Kant to speculation in Germany, and was perhaps 
 the true originator of the English School of Philosophers 
 which seeks to explain the belief in an external world as a 
 natural illusion arising from the operation of the principle of 
 Association of Ideas on original sensations — sensations which 
 they describe as mental feelings and nothing more. In this 
 state Sir W. Hamilton found the controversy, and with the 
 ardour of a true philosopher he resolved, if possible, to clear 
 up the point in dispute, 
 
 I am using the phrase External World in the vulgar sense. 
 The vulgar believe that the external world is something real,, 
 which exists independent of me or of any other mind (except 
 possibly that of the Creator), and which would equally con- 
 tinue to exist if all finite minds were annihilated. They also 
 believe that this world exists in space, and that the space 
 which contains it, and which it occupies, is equally in- 
 dependent of my own, or of any other mind. No man who 
 has not been instructed in philosophy believes that space, as 
 it exists in bodies, is nothing but the unknown cause of 
 certain sensations in us, and that space, as we perceive or 
 represent it, is purely and exclusively mental. This preface 
 is necessary, because it has lately become fashionable with 
 Idealists, instead of denying the existence of an external 
 world, to admit that in a certain sense it exists, and then to 
 give an explanation which denies its existence in the only 
 sense which the vulgar attach to it. But the question is 
 further perplexed by the introduction of ambiguous and in- 
 
NATURAL REALISM. 17 
 
 definite language, which is perhaps understood in one meaning 
 by the writer, and in another by the reader. Thus we are 
 told that Matter is admitted to exist in the sense of a Per- 
 manent Possibility, or Potentiality, of Sensations. This ex- 
 pression is susceptible of two contrasted meanings. It may 
 sig'nify a i/iiiiff which renders sensations permanently possible 
 '—a thing that causes sensations — which is probably what 
 the casual reader would understand by it ; or it may mean 
 only that it is permanently possible for my mind (or some 
 other mind) to feel certain sensations when certain conditions 
 (these conditions being purely mental) are supplied. It may, 
 in short, mean either Permanent Possibility oi producing i\iQ 
 sensations, or a Permanent Possibility of ytfe/iw^ them. In the 
 latter sense it can exist nowhere but in a mind, and its existence 
 there was probably never disputed by any Idealist. The 
 vulgar belief undoubtedly goes beyond this. But if it be 
 asked whether the external world in which the vulgar believe 
 is substance or attribute, the answer is not so clear. The 
 distinction of substance and attribute is one about which the 
 vulgar give themselves little concern, and if an external 
 world be conceded to them, they would not perhaps care ver}- 
 much whether it was called a substance, or a collection of 
 qualities or attributes — always assuming that these attributes 
 or qualities are admitted to exist independently of the pei- 
 ceiving mind. 
 
 It was a common practice with the earlier philosophers, as, 
 for instance, with Ijocke, to say that we knew material objects 
 by means of our ideas of them. These ideas, it was said, 
 truly represented the objects, and Locke even carelessly wrote 
 that our ideas of the primary qualities of matter were 
 " resemblances " of these qualities. Locke defined an idea as 
 " the immediate object of our minds in thought," or in " think- 
 ing;" but then he described sensation as one of the modes 
 
 c 
 
1 8 SIR WILLIAM HABIILTON. 
 
 of thinking, and he usually employed the phrases "sensation/' 
 " idea of sensation/^ and " sensitive idea/' in the same sig- 
 nification. Dr. Reid, however, interpreted the word idea as 
 used by Locke and a great number of other philosophers, as 
 meaning not a mere mental state, but a thing in the raind, 
 or even in the brain ,: and he understood them as maintaining 
 that it was this thing, and not the real external thing, which 
 was immediately perceived, or known, in every exercise of the 
 senses. The idea was thus (as Reid interpreted his pre- 
 decessors) a third thing — an intermediate — interposed between 
 the mind and the external world, and was the immediate 
 object of perception, while the real external world could 
 only be perceived mediately and through it. How far Reid 
 correctly understood his predecessors, I need not now inquii'e. 
 There is no doubt that, with regard to some of them, he was 
 mistaken ; and it is also certain that, since his time, no one 
 has ventured to advocate the theory of ideas in the shape in 
 which he opposed it. It is easy to see that this theory of 
 ideas (or ideal theory) was fatal to the external world. Ac- 
 cording to it, the external world was not perceived at all. 
 Nothing was perceived but the idea. How, then, were we 
 justified in believing that anything existed except the idea 
 which alone was perceived ? Or if an external world existed, 
 how could we know that it resembled the idea? The idea was 
 alleged to be a jncture, but we could never get the original to 
 compare it with. We could not, therefore, tell whether it was 
 a good or a bad likeness, or whether it was a likeness at all. 
 Nay, we could not know that there was any original. We 
 perceived the idea and nothing else. Why, then, should we 
 assume that there was anything else to be perceived ? 
 
 Reid easily saw that the Ideal Theory, as be understood it, 
 destroyed the proof of the external world, and finding that 
 Revkeley had founded his Idealism on Locke's admission that 
 
NATURAL REALISM. 19 
 
 we pciTcive not the extevnal things themselves, but only our 
 ideas of them, he was naturally led to deny the existence of 
 ideas and to maintain that we perceive external objects im- 
 mediately and not through the medium of these supposed ideas. 
 He extended this doctrine to memory and imag-ination. There 
 was there also no third thing — -no separate entity — between 
 the mind and the object which we remembered or imagined. 
 There was no intervening idea, and our knowledge was in these 
 cases also immediate. It is surprising, when Reid had got so 
 far as this, that he did not see that whether he had refuted 
 Berkeley or not, the problem of the external world was still 
 unsolved. Memory sometimes deceives us. Imagination often 
 does. Why then should not percei)tion deceive us also, since 
 all three are on a level as immediate cognitions? Reid 
 appealed to our natural belief in the external world. But 
 what he was called upon to do, was to justify this belief, to 
 point out its grounds, and to defend it against objections ; 
 and it can hardly be said that this was done, either by Reid 
 himself or by his successor Stewart. 
 
 In the meantime Hume had attached a new meaning to 
 the word " idea " which his disciples appear disposed to ascribe 
 to earlier philosophers to whose systems it is quite alien.' . 
 Hume did not believe in the idea as a separate entity — an 
 intermediate thing — existing in the mind or in the brain; 
 but he distinguished between the sensation or original feeling 
 and its subsequent representation in the imagination, to which 
 latter alone he gave the name idea. When the term idea had 
 got this meaning, the doctrine of perception by means of 
 ideas got a new meaning also. It no longer meant perception 
 by means of intermediate things — separate entities — but per- 
 
 ' Mr. Mill, for instance, more than once criticizes Locke on the assump- 
 tion that that philosopher used the term "idea'' in the same sense as 
 Hume and James Mill. This is not the case, as already remarked. 
 
 c 2 
 
20 SIR WILLIAM HAMILTON. 
 
 ceptiou by means of states of mind which, however; belonged 
 to reproductive or representative, rather than to orig'iiial or 
 presentative, consciousness. Now it could not be doubted that 
 there were such states of mind. I can call up, for instance, a 
 mental representation of a house, a bridge, or a man that I saw 
 yesterday or the day before. Consequently Reid's assertion, 
 that there were no ideas, would not apply to this new form of 
 the theory. But it was evident that the external world fured 
 no better on this tlieory than on the former one. If my 
 mental state when I looked at St. Paul's cathedral was of the 
 same nature with my mental state when, after leaving London, 
 I merely imagined it, and if the former state only differed 
 from the latter by being moie vivid, or more clear and distinct, 
 the one could no more prove the existence of the cathedral 
 than the other. Men can imagine things that never existed 
 and never will exist; and if perception is a mental state similar 
 in all its essentials to imagination, why may we not also per- 
 ceive things that never existed and never will exist ? When 
 I am said to be looking at St. Paul's cathedral, I have, on 
 this theory, the representation of the cathedral in my mind ; 
 but how can I know whether it is like or unlike the orio-inal, 
 or whether there is any original ? I know nothing but the 
 representation, and the representation is purely and exclu- 
 sively mental. How can I get beyond it to reach any 
 external world ? The philosophy of Reid can here afford us 
 but little assistance. 
 
 In this exigency the majority of philosophers seem to have 
 fallen back on the Principle of Causality. This principle has 
 been variously understood. With some it affirms nothino- 
 more than certain uniformities of succession in our mental 
 states. Such a principle is here useless. The antecedent 
 state would always be as strictly and exclusively mental as its 
 successor. It might indeed be a mental state which we did 
 
NATURAL REALISM. 21 
 
 not actually experience, but then the statement that it was an 
 antecedent would only mean that some one else experienced 
 it or that we would have experienced it under other circum- 
 stances — circumstances purely mental. Pursuing trains ol' ante- 
 cedents and consequents in our mental states can never lead us 
 to anything that is not a mentiil state, any more than tracing 
 the terms of arithmetical series could lead to the discovery of 
 a new chemical substance. But more usually the principle 
 seems to have been understood as asserting that everything 
 that begins to exist has an efficient cause — a cause which has 
 produced it by an exertion of power. Our sensations, then, it 
 was alleged, had causes, and we inferred the existence of matter 
 or of the external world, as the (otherwise unknown) cause of 
 our sensations. But then the question revived in this form : 
 How do I know that this unknown cause of my sensations 
 may not be another mind — God, for instance, as Berkeley 
 maintained ? Or, how do 1 know that my own mind may not 
 unconsciously produce these sensations, as it seems to do, for 
 instance, in dreaming ? Or even assuming that the unknown 
 cause is not a mind, how am I justified in ascribing any of the 
 properties of the effect to it ? The cause of my feeling of 
 extension may not be extended : the cause of my feeling of 
 solidity may not be solid : the cause of my feeling of figure 
 may not be figured. Causes are by no means invariably 
 similar to their effects : and, indeed, if the cause of my sensa- 
 tions resembles these sensations, seeing that the sensations 
 are wholly mental, must not their cause be wholly mental 
 also ? 
 
 The problem would here seem to be reduced to the following 
 question : Do we know the external world otherwise than as 
 the cause of our (mental) sensations ? This is the form in which 
 Hamilton has grappled with it, and this is the question which 
 he has answered in the aflBrmative. His discussion has, indeed, 
 
22 SIR WILLIAM HAMIL TON. 
 
 suffered from his having treated the subject too exclusively in 
 its historical connexion with Reid and Brown ; but his solution 
 of the problem is nevertheless sufficiently clear, and it appears 
 to be the only one on which the existence of a veritable 
 external world is likely to be maintained for the future. 
 
 It would be foreign to the purpose of the present work to 
 enter into a discussion of the historical questions in dispute at 
 any considerable length. Erown understood Raid as merely 
 denying the existence of the idea in the sense of a separate 
 entity or intermediate thing, and asserting that the perception 
 of matter takes place without the intervention of any such 
 medium. Understanding Reid in this sense, Brown contended 
 first that very few jjhilosophers ever believed in the inter- 
 mediate idea or separate entity ; and, secondly, that Reid'sown 
 theory left the existence of the external world open to all the 
 same objections as before. Hamilton controverted both of these 
 assertions, and retorted that Browne's own theory subverted 
 the existence of the external world altogether. That Hamil- 
 ton was right in the main portion of bis argument is practi- 
 cally admitted by Mr. Mill in the last edition of his Examina- 
 tion of Sir William Hamilton's Philosophy . He there con- 
 fesses that the Cosmothetic Idealists (the class of philosophers 
 to which Brown admittedly belonged) cannot make good their 
 case against Berkeley, which was, in fact, the substance of 
 Hamilton's contention against them; while he allows that 
 Hamilton escapes from Berkeley's argument by his doctrine 
 that matter, with its primary and secundo- primary qualities, 
 is directly and immediately perceived.' Again, he grants that 
 Reid, like Sir W. Hamilton, aifirmed, while Brown denied, 
 that we have a direct intuition of the primary qualities of 
 bodies ; ^ and, as will be seen presently, the controversy 
 
 ' Examination of Samilion, p. 207, note (4tli Edition). 
 « Id. p. 223 (4th Edition). 
 
NATURAL REALISM. 23 
 
 related to the perception of material qualities only, no philo- 
 sopher having been bold enough to maintain that we have a 
 direct intuition of material substance. Granting therefore to 
 Reid his premisses, he was, by Mr. MilFs admission, in a 
 position to resist Berkeleianism. Granting to Brown his 
 premisses, Mr. Mill equally concedes that he only reached the 
 external world by a paralogism. Hamilton is therefore 
 triumphant in this branch of the controversy. 
 
 Hamilton's doctrine, which he designates Natural Realism, 
 asserts that we have a direct and immediate consciousness of 
 the external world as really existing, and are not left to infer 
 its existence from the sensations which it is supposed to 
 produce, or from the ideas which are supposed to resemble (or 
 represent) it, or even from a blind faith in its existence, which 
 says " I believe," but can give no reason for believing. I 
 believe that it exists, says Hamilton, because I know it — T 
 feel it — I perceive it — as existing. It becomes necessary, 
 however, to examine with care what external world, according 
 to him, we perceive, and on this point his works are not 
 in complete harmony with each other. He everywhere, 
 indeed, repudiates a direct perception of material substance, 
 but then the mental substance is according to him equally 
 unknown. One of the strongest passages to this eflfect occurs in 
 the eighth of his Lectures on Metaphysics, where he expounds 
 the axiom that all human knowledge is only of the relative 
 and phsenomenal. " Our knowledge," says he, " is either of 
 matter or of mind. Now what is matter ? What do we know 
 of matter ? Matter or body is to us the name either of some- 
 thing known, or of something unknown. In so far as matter 
 is a name for something known, it means that which appears 
 to us under the forms of extension, solidity, divisibility, 
 figure, motion, roughness, smoothness, colour, heat, cold, &c. ; 
 in short, it is a common name for a certain series or aggre- 
 
24 S/R WILLIAM HAMILTON. 
 
 gate or complement of appearances or phsenomena, manifested 
 in co-existence. 
 
 " But as these plisenomena appear only in conjunction, we 
 are compelled, by the constitution of our nature, to think 
 them conjoined in and by something, and as they are phaeno- 
 mena we cannot think them the phsnnomena of nothing, but 
 must regard them as the properties or qualities of something 
 that is extended, solid, figured, &c. But this something 
 absolutely, and in itself — i. e. considered apart from its phseuo- 
 mena — is to us as zero. It is only in its qualities, only in its 
 effects, in its relative or phaenomenal existence, that it is 
 cognizable or conceivable ; and it is only by a law of thought 
 which compels us to think something absolute and unknown 
 as the basis or condition of the relative and known, that this 
 something obtains a kind of incomprehensible reality to us. 
 Now that which manifests its qualities — in other words, that 
 in which the appearing causes inhere — that to which they 
 belong — is called their subject, or substance, or substratum. 
 To this subject of the phsenomenn of extension, solidity, &c., 
 the term matter or material substance is commonly given, 
 and therefore as contradistinguished from these qualities it is 
 the name of something unknown and inconceivable. 
 
 " The same is true in regard to the term mind. In so far 
 as mind is the common name for the states of knowing, 
 willing, feeling, desiring, &c., of which I am conscious, it is 
 only the name for a certain series of connected phsenomena or 
 qualities, and consequently expresses only what is known. 
 But in so far as it denotes that subject or substance in which 
 the phsenomena of knowing, willing, &c., inhere — something 
 behind or under these phasnomena — it expresses what in itself, 
 or in its absolute existence, is unknown. 
 
 "Thus mind and matter, as known or knowable, are only 
 two different series of phsenomena or qualities ; mind and 
 
NATURAL REALISM. 25 
 
 matter, as unknown and unknowable, are the two substances in 
 which these two different series of phasnomena or qualities are 
 supposed to inhere. The existence of an unknown substance 
 is onl}' an inference we are compelled to make from the exis- 
 tence of known phsenomena ; and the distinction of the twa 
 substances is only inferred from the seeming incompatibility of 
 the two series of phaenomena to coinhere in one'" [substance].' 
 
 To this doctrine Hamilton steadily adhered throughout his 
 writings ; and therefore a theorj'' of the external world, which 
 merely seeks to explain the origin of our idea of material 
 substance does not necessarily conflict with our author's 
 Natural Realism. No doubt he believed that the notion of 
 substance and the principle which leads us to refer every 
 phsenomenon to a substance, are both a priori and incapable 
 of being explained by experience or association of ideas. But 
 his theory of substance formed no element in the doctrine of 
 Natural Realism, which he bequeathed to the world as, per- 
 haps, his most valuable contribution to philosophy. That 
 doctrine relates to material attributes or phsenomena only. 
 And it may be remarked that Hamilton uses the term phseno- 
 menon in the meaning of attribute, property, or quality, as 
 opposed to substance, and not in the Kantian sense as opposed 
 to thing j!)(?r se, or Noumenon. That we perceive qualities, 
 not substances, is certainly the leading element in his doctrine 
 of relativity. He then adds that things may have a great 
 many qualities which we do not perceive, but which we would 
 perceive if we had additional senses; and though these two 
 heads can hardly be said to exhaust the whole of his doctrine 
 of relativity, they go very far towards doing so. 
 
 We have then, according to Hamiltoni a direct intuitive per- 
 ception of the qualities, attributes, or phaenomena of matter, 
 just as as we have of the qualities, attributes, or phsenomenat 
 • Lectures, i. pp. 137-8. 
 
26 SIR WILLIAM HAMILTON. 
 
 of mind, the substances ia both cases being equally unknown. 
 "But have we this knowledge of some of the properties or 
 qualities of matter, only, or of all of them ? And do we per- 
 ceive these qualities in all matter alike, or in so much of it 
 as comes in contact with our bodily organism, or only in our 
 material organism itself? In dealing with the first of these 
 questions, it is to be observed that Hamilton in some places 
 makes a distinction between primary and secondary qualities 
 of matter, while in others he enumerates three classes, 
 primary, secundo-primary, and secondary ; and in some 
 passages he has been understood as excluding at least the 
 secondary qualities from his Natural Realism. Thus, for in- 
 stance, we find him saying : " Under the primary [qualities] 
 we apprehend modes of the non-ego : under the secundo- 
 primary we apprehend modes both of the ego and of the 
 non-ego : under the secondary we apprehend modes of the 
 ego, and infer modes of the non-ego. The primary are 
 apprehended as they are in bodies ; the secondary as they are 
 in us ; the secundo-primary as they are in bodies and as they 
 are in us." ' Again : " We are conscious as objects in the 
 primary qualities of the modes of a not-self ; in the secondary 
 of the modes of self; in the secundo-primary of the modes of 
 self and of a not-self at once." ^ The secondary qualities it would 
 thus seem are not perceived, but inferred from our sensations. 
 The colour of the tree before me, for instance, is not an object 
 of direct perception, but is merely au unknown something that 
 produces in me the sensation of colour, and this sensation is 
 all that I am really conscious of. But Hamilton's doctrine on 
 the subject of secondary qualities must not be confounded 
 with that commonly held by his predecessors. For Hamilton's 
 ego or self does not consist of the mind to the exclusion of 
 the body, nor is sensation with him a mere mental feeling. 
 
 ' KeiJ, p. 857 (a) (Hamilton's Edition). * jggjj^ p_ §53 ^^^^ 
 
NATURAL REALISM. 27 
 
 The secondary qualities, as they exist in external or extra- 
 organic bodies, are indeed (in his opinion) unknown, and are 
 only inferred as causes of our sensations ; but it is otherwise 
 as regards our bodily organism itself. In a note appended 
 to the last passage I have cited, he says : " Our nervous 
 organism, in contrast to all exterior to itself, appertains to 
 the concrete human ego, and in this respect is subjective, 
 internal ; whereas, in contrast to the abstract immaterial ego 
 — the pure mind — it belongs to the non-ego^ and in this re- 
 spect is objective, external." ' And he then goes on to point out 
 that, even within this animated organism, a further distinction 
 is admissible, and that some of its affections may be regarded 
 as in a special sense atfections of the ego, while others are in 
 a special sense aflFections of the non-ego ; the former cor- 
 responding to the secondary, and the latter to the primary 
 qualities of matter. A very similar note occurs at p. 880 
 of his edition of Reid, where the same subject is discussed in 
 connexion with the distinction between Sensation and Per- 
 ception, and where in the text he says : " The organism is 
 the field of apprehension both to Sensation proper and Per- 
 ception proper ; but with this difference, that the former 
 views it as of the ego, the latter as of the non-ego." We are 
 conscious, according to Hamilton, in every act of sensation, 
 not merely of the mind as affected, but of an "organic affec- 
 tion,^' which he thinks is always attended with some reference 
 to " locality." "I hold," says he, " with Aristotle— indeed 
 with philosophers in general — that sensation is an affection 
 neither of the body alone nor of the mind alone, but of the 
 composite of which each is a constituent."^ And as the 
 secondary qualities are apprehended as they exist in our own 
 organism (though not as they exist in extra-organic bodies), 
 Hamilton proposes to employ the phrase " secondary quality " 
 • Reid, p. 858 (a) note. « i^gja, p. 884 (a). 
 
28 SIR WILLJAM HAMILTON. 
 
 only in reference to that whinh is immediately known, and 
 not in relation to its unknown cause. "I shall employ/' 
 says he, " the expression secondary/ qualities to denote those 
 phsenomenal affections determined in our sentient organism 
 by the agency of external bodies, and not (unless when other- 
 wise stated) tne occult powers themselves from which that 
 agency proceeds." As thus understood, secondary qualities 
 are as much the object of direct apprehension ^ as the primary 
 or secundo-primary, and they are perceived as modes of 
 matter no less than of mind. The}' reveal to us states of our 
 own organized bodies, but not of the extra-organic world. 
 If the tree I look at is not coloured, but merely produces in 
 me the sensation of colour, it is otherwise with the organism 
 of my eye. Colour is a real affection of that organism, and 
 the retina may be trul}' said to be coloured, though the tree is 
 not. Such is Sir William Hamilton's doctrine of secondary 
 qualities. 
 
 Hamilton attached perhaps an exaggerated importance to 
 the scholastic axiom that a thing can only act where it is, 
 and hence concluded that the only extra-organic matter which 
 we can immediately perceive is that which is in immediate 
 contact with our bodily organism. The mind, according to 
 his view, is not located merely in the brain, but is vitally 
 united with the nervous organism iu its whole extent, and 
 therefore whatever comes in contact with the organism at any 
 part of the body is capable of being directly and immediately 
 perceived. Whenever he comes to deal formally with the 
 question, he denies the possibility of an immediate perception 
 of the distant, though in some casual illustrations he speaks 
 as if the distant object was immediately perceived. Once, too, 
 he appears to have been shaken in this theory of contact by the 
 indications of an immediate perception of distance afforded by 
 1 Reid, p. 854 (b). ^ See Keid, p. 810 (b). 
 
NATURAL REALISM. 29 
 
 the actions of some of the lower animals ; ' but no trace of this, 
 doubt appears elsewhere in his works. All the senses are, he 
 maintains, modifications of the sense of touch — absolute con- 
 tact between the external object and the sensitive organ being 
 alike requisite to the exercise of each. But while absolute contact 
 is thus necessary in oxi^ax \x> produce the sensorial affection, the 
 question remains whether what we perceive is merely the sen- 
 sorial affection thus produced, or also the extra-organic body 
 whose contact produces it. There are some ambiguities and in- 
 consistencies in Hamilton's language on this subject. When he 
 speaks, lor instance, of the rays of light in contact with the re- 
 tina as the object of vision, the word " object •" may be taken to 
 mean either that whijh is perceived, or that which immediately 
 causes the perception. In the Dissertations appended to his 
 €ditionofReid, he states unequivocally that the primary quali- 
 ties of matter are perceived in our organism only, and that it is 
 by induction and inference that we learn the existence of similar 
 properties in extra-organic bodies;^ but in an earlier note to 
 the same work he had affirmed that in vision we have a direct 
 cognition of the direction in which the rays fall upon the 
 retina,' which seems to imply (as do also other expressions in 
 the same note) that we have an immediate cognition of the 
 rays themselves as well as of the sensorial affection produced 
 by them. Again, he speaks of " outness '■" (though not 
 distance) as a direct perception of sight, and insists that 
 Cheselden's patient enjoyed this natural perception from the 
 first, and that what he was conscious of was not " a mere 
 affection of the organ." ^ More than once, too, he speaks as 
 if the object of perception was a sort of composite made up 
 of the sensitive organism and the extra-organic object in eon- 
 tact with it, as will be seen in one of the notes already 
 
 ' Lect. ii. p. 181, seq. ^ Rgjj^ p gsi (b). 
 
 » Reid, p. 160, note. ■* Reid, p. 177, note. 
 
30 SIR WILLIAM HA MIL TON. 
 
 referred to. But his maturer doctrine would seem to be that 
 in the perception of the primary, no less than of the secondary 
 qualities of matter, we are conscious of affections of our own 
 organism only, and not of anything outside or beyond it. The 
 primary qualities are affections of that organism as material or 
 extended — as a part of the non-ego : the secondary qualities 
 are affections of it as animated, and regarded as a part of the 
 ego.^ In neither case do we get out o£ our own organism.^ 
 
 Hamilton even thought it possible that what we imme- 
 diately perceive is not the whole nervous organism as affected, 
 but only the nerve-extremities which terminate in the brain. 
 If we had a direct pereeptiim of matter in any shape, he 
 seemed to regard it as sufficient for his purpose. Allow him 
 any hold, however small, on the external world, and he 
 believed he could show how the rest might be reached ; but 
 unless some portion of it could be attained directly, we could 
 obtain no sure foothold outside of what he designates " the 
 pure immaterial ego." " It makes no essential difference in 
 this doctrine,'" says be, " whether the mind be supposed 
 proximately conscious of the reciprocal outness of sensations 
 at the central extremity of the nerves in an extended sensorium 
 commune, where each distinct nervous filameut has its separate 
 locality, or at the peripheral extremity of the nerves in the 
 places themselves where sensations are excited, and to which 
 they are referred. From many pathological phaeuomena," he 
 
 ' See Eeid, p. 858, note. 
 
 ^ This view was probably suggested to Hamilton by the difficulty of 
 obtaining any instance in which thei'e is an absolute contact between 
 the extra-organic body and the nervous organism with which the mind is 
 supposed to be vitally united. In most cases the skin at least intervenes 
 between the outward body and the sensitive nerve. In his last fragment 
 on the subject, however, Hamilton seems disposed to revert to his original 
 view, that we have a direct perception of so much of the extra -organic 
 body as is in contact with our organism (Lect. ii. pp. 522-3). 
 
NATURAL REALISM. .^i 
 
 addsj " the former alternative might appear the more pro- 
 bable." ' Such a theory would of course not only exclude the 
 perception of extra-org-anic matter in sensation, but limit oui 
 perception of organic extension to the brain. Hamilton does 
 not positively adopt it, but regards it as fairly admissible. 
 
 His mode of reaching the extra-organic VForld was through 
 the locomotive faculty, or the power of muscular effort. This 
 must be distinguished from the muscular sense (or the sensa- 
 tions accompanying our muscular motions), which is, in his 
 opinion, as incapable of attaining anything outside our or- 
 ganism as the other senses are. But it is different, he thinks, 
 with the active effort to move. This, when resisted, makes 
 us aware not only of the feeling of resistance, but of a some- 
 thing that resists us ; and this something is not merely 
 inferred as the unknown cause of the resistance which we 
 feel, but is perceived with the same directness and immediate- 
 ness as that resistance itself So at least I understand his 
 doctrine, which may perhaps be gathered from the following 
 passages : " How is this resistance perceived ? I have fre- 
 quently asserted that in perception we are conscious of the 
 external object immediately and in itself. This is the doctrine 
 of Natural Realism. But in saying that a thing is known in 
 itself I do not mean that this object is known in its absolute 
 existence — that is, out of relation to us. This is impossible, 
 for our knowledge is only of the relative. To know a thing 
 in itself, or immediately, is an expression I use merely in 
 contrast to the knowledge of a thing in a representation or 
 mediately. On this doctrine an external quality is said to be 
 known in itself when it is known as the immediate and neces- 
 sary correlative of an internal quality of which I am conscious. 
 Thus when I am conscious of the exertion of an enorganic voli- 
 tion to move, and aware that the muscles are obedient to my 
 
 ' Reid, p. 861, note. 
 
32 S/R WILLIAM HAMILTON. 
 
 will, but at the same time aware that my limb is arrested in 
 its motion by some external impediment — in this case I can- 
 not be conscious of myself as the resisted relative, without at 
 the same time being- conscious — ^being- immediately percipient 
 — of a not-self as the resisting- correlative. In this cognition 
 there is no sensation — uo subjectivo-orgauic affection. I 
 simply know myself as a force in energy, the not-self as a 
 counter-force in energy." ' Tliis resistance in its several 
 modes constitutes what Hamilton designates the secundo- 
 primary qualities of matter, which alone, according to him, 
 reveal to us the extra-organic world. " The existence of au 
 extra-organic world," says he, " is apprehended not as a per- 
 ception of the primary qualities, but in a perception of the 
 quasi-primary phasis of the secundo-primary " [qualities]; 
 " that is, in the consciousness that our locomotive energy is 
 resisted, and not resisted by aught in our organism itself. 
 For, in the consciousness of being thus resisted, is involved as 
 a correlative, the consciousness of a resisting something ex- 
 ternal to our organism. Both are, therefore, conjunctly ap- 
 prehended .''■' ^ 
 
 This volition which is resisted is a volition to move our 
 bodies, and consequently Hamilton immediately adds: — 
 "This experience presupposes, indeed, a possession of the notions 
 of space and motion in space." And if the space, in which 
 our bodies are supposed to be moving, is a purely mental form 
 which has no existence out of the ego, as Kant maintained, 
 the motion of our bodies through space, and the resistance to 
 tliat motion which we experience, must be regarded as not 
 less subjective and mental than space itself. But Hamilton 
 adopted the Kantian doctrine, so far as to maintain that space 
 is a native, or a priori notion — a mental form derived from 
 the very constitution of the mind itself, and which it would 
 1 Eeid, p. 866, note. ^ Reid, p. 882. 
 
NATURAL REALISM. 33 
 
 have equally possessed if there was no external world. A new 
 difficulty was thus placed ia the way of Natural Realism. 
 How can the external world be real, if the space which 
 contains it, and which it fills and occupies, is ideal ? 
 
 Hamilton's reply to this question was that Space (and Time 
 also) is not purely mental or ideal. Space and Time are 
 not merely forms of thought. They are also " conditions of 
 things ;" and besides our a priori knowledge of space as a 
 mental form, we have an a posteriori knowledge of it as aa 
 element of existence.' This doctrine has been censured as 
 unphilosophical ; but while many writers have put forward 
 strong grounds for maintaining that our idea of space is 
 native or a priori, it must be confessed that Hamilton has 
 likewise assigned good reasons for regarding it as a direct 
 apprehension of our sensible experience. And, indeed, Platner 
 appears to have advocated a doctrine similar to that of Hamil- 
 ton on very similar grounds.' Hamilton's principal argument 
 that space or extension is directly attained by the sense of 
 sight is as follows : — " We have by sight a perception of 
 colours, consequently a perception of the difference of colours. 
 But a perception of the distinction of colours necessarily in- 
 volves the perception of a discriminating line; for if one 
 colour be laid beside or upon another, we only distinguish 
 them as different by perceiving that they limit each other, 
 which limitation necessarily affords a breadthless line — a line 
 of demarcation. One colour laid upon another, in fact, gives 
 a line returning upon itself, that is a figure. But a line and 
 a figure are modifications of extension. The perception of 
 
 1 Lect. i. 403; ii. 114. Reid, 126, note; 841(a), 882 (b). It is strange 
 that in the face of all these passages (see especially 841 (a) ) the late Dean 
 Mansel should have apparently regarded Hamilton's doctrine of space as 
 identical with his own. 
 
 2 Lect. ii. 173. 
 
 O 
 
34 SIR WILLIAM HAMILTON. 
 
 extension is, therefore, necessarily given in tlie perception of 
 colours." ' The space-perceptions of the lower animals also 
 come in to prove the empirical perception of space, and 
 Hamilton insists on another principle, viz. that the imagina- 
 tion, in representing any sensible object, makes use of the 
 organ of sense, by which that object was originally perceived ; 
 whence he contends that since we always represent space in 
 imagination as coloured, the perception of space must have been 
 arrived at through the sense of sight." Platner had gone farther, 
 and maintained, as a result of his own observations on a man 
 born blind, that those who have always been destitute of the 
 sense of sight are likewise destitute of the perception of space or 
 extension ; ^ but his observations are not wholly satisfactory, 
 and Hamilton, in quoting the passage, does not express his 
 complete concurrence in Platner's conclusion. Indeed, he else- 
 where expresses an opinion that there is some perception of 
 space - at all events, of locality — in the everj' exercise of any 
 of our senses ; but his arguments in favour of an empirical 
 cognition of space are mainly derived from the sense of sight. 
 Sir William Hamilton's arguments in favour of this theory 
 of Natural Realism are two-fold, positive and negative. The 
 positive argument consists of a direct appeal to consciousness 
 — that is, not merely to the consciousness of the individual, 
 but to the general consciousness of mankind, as attested by 
 their expressions and actions. This latter argument is what 
 is known as appealing to Common Sense. " To say that all 
 
 ' Lect. ii. 165. Hamilton takes no notice of the motions of the eye 
 and the muscular sensations which accompany them : but there are stroD<»' 
 reasons for believing;, 1st, that we can perceive extension when the eye is 
 at rest; and 2ndly, that the njotions of the eje mainly act by altering the 
 optical or visual impressions themselves, rather than by associating those 
 impressions with muscular sensations, or muscular movements, of our arms 
 or legs. 
 
 3 Lect. ii. 168-9. 3 Lg^t ;; yj^ 
 
NATURAL REALISM. 35 
 
 men naturally believe in such a knowledge," says Hamilton, 
 " is only, in other words, to say that they believe it upon the 
 authority of eonsciousnoss. A fact of consciousness, and a 
 fact of the common sense of mankind, are only various ex- 
 pressions of the same import," ' But no philosopher can 
 consistently reject any portion of the testimony of couscious- 
 Dess; and as it testilies to our immediate perception or cogni- 
 tion of the external world, every philosopher is bound to 
 accept this testimony as an ultimate truth. We do not find 
 in consciousness a mere belief that the external world exists ; 
 we find there a belief that we perceive it — know it — as exist- 
 ing. Convince me, says Hamilton, that I am wrong in 
 thinking that I perceive the external world, and I will readily 
 grant that I am also wrong in believing in its existence. My 
 only reason for believing that it exists, is my belief that T 
 perceive it, and if the latter belief is to be abandoned or 
 declared an illusion, the former must fall along with it, 
 Hamilton would, in some passages, appear, like Reid, to be 
 the advocate of the popular belief in its entirety ; but, taking 
 his writings as a whole, it seems clear that his object was 
 rather to point out the element of truth on which the popular 
 belief reposed — to show that it was not a total error, a mere 
 delusion — and that though we did not immediately perceive 
 so large a portion of the external world as the vulgar sup- 
 posed, we had an immediate perception of some of it, and that 
 from the portion which we perceived, the remainder could be 
 inferred by a simple and legitimate process.^ "The first 
 problem of philosophy," he tells us, is " to seek out, purify, and 
 
 ' Lect. i. 292. 
 
 ^ Accordingly we find Hamilton saying, " It is sufficient to establish 
 the simple fact tliat we are competent, as consciousness assures us, to 
 apprehend, through sense, the non-ego in certain limited relations ; and it 
 is of no consequence whatever, either to our certainty of the reality of 
 
 D I 
 
36 S/R WILLIAM HAMILTON. 
 
 establish^ by intellectual analysis and criticism, the elementary 
 feelings or beliefs, in which are given the elementary truths, 
 of which all are in possession ; and the argument from 
 Common Sense being the allegation of these feelings, as ex- 
 plicated and ascertained, in proof of the relative truths and 
 their necessary consequences, this argument is manifestly 
 dependent on philosophy as an art — as an acquired dexterity— 
 and cannot, notwithstanding the errors they have so frequently 
 committed, be taken out of the hands of the philosophers. 
 Common Sense is like Common Law. Each may be laid 
 down as the general rule of decision, but in the one case it 
 must be left to the jurist, in the other to the philosopher, to 
 ascertain what are the contents of the rule ; and though in 
 both instances the common man may be cited as a witness for 
 the custom or the fact, in neither can he be allowed to officiate 
 as advocate or as judge;" ' and he immediately afterwards pro- 
 ceeds to blame some of the Scottish philosophers for not pro- 
 claiming that the argument from Common Sense was " no 
 appeal to the undeveloped beliefs of the unreflective many,'' 
 and for not inculcating that it "presupposed a critical analysis 
 of these beliefs by the philosophers themselves." When the 
 original facts of consciousness are thus separated by analysis 
 from the portions of our acquired knowledge, which in the 
 vulgar mind is intimately connected with them, the philo- 
 sopher can appeal to the vulgar in support of his theory. 
 Perhaps the most remarkable instance of a vulgar error that 
 history records is the popular belief prior to the time of 
 Copernicus, that the heavenly bodies revolved round the earth 
 every twenty-four hours. The Copernican theory was at first 
 
 a material world, or to our ultimate knowledge of its properties, whether 
 by this primary appreliension we lay hold, in the first instance, of a 
 larger or a lesser portion of its contents." (Reid, p. 814 (a).) 
 ' Reid, 752 (a). 
 
NATURAL REALISM. 37 
 
 regarded as a strange paradox, but its advocates were able to 
 point out many instances in which our own motions produced 
 the same sensible effects as those of external bodies — in which, 
 when we ourselves moved, the body we were looking at ap- 
 peared to do so. There was thus an element of truth in the 
 popular belief. There was a motion and a motion of revolu- 
 tion, though not that which mankind in general supposed. 
 Now if a controversy had afterwards arisen between the 
 Copernicans, and another school of philosophers who denied 
 that there was any motion at all in the case and explained 
 the whole appearance as an illusion, the Copernicans would 
 have been justified in appealing to the popular belief of man- 
 kind in proof Ihat there was really some motion or otbei', and 
 a motion which produced similar effects on the senses to that 
 which the vulgar believed in. This example will illustrate 
 the position of Sir William Hamilton in relation to the 
 Idealists. He admits that when the vulgar believe in the 
 immediate perception of a non-ego outside of, and at a dis- 
 tance from, our bodily organism, they ai'e in error ; and yet 
 he appeals to their belief as a proof that some external non- 
 ego is perceived, and that the idealistic theory which explains 
 this non-ego and its externality as a total delusion, is erroneous. 
 But Hamilton goes beyond this, and maintains that even the 
 philosophers who denied that we have an immediate perception 
 of the external world are compelled to admit that conscious- 
 ness attests the contrary, and to allege that consciousness is 
 in this respect mistaken.' It would be impossible here to 
 examine these quotations in detail, but it may be remarked 
 that according to many philosophers our original conscious- 
 ness becomes largely modified by experience and association, 
 and the additions thus made to it acquire all the appearance 
 
 ' Keid, pp. 747-8. Lect. i. 289-92. See, however, as to Descartes, 
 Reid, 964 (b), and as to Brown and others, Lect. ii. 106. 
 
38 SIR WILLIAM HAMILTON. 
 
 of originality, and, in fact, become inseparable from the parts 
 which are really original. Consciousness thus very soon 
 arrives at a stage at which its original deliverances are not to 
 be distinguished from subsequent acquisitions by any effort of 
 reflexion, or, to use Mr. Mill's phrase, of introspection ; and 
 a philosopher who entertains this opinion may admit that 
 our present consciousness testifies to the (apparently) imme- 
 diate perception of an external world, while denying that our 
 original consciousness did so. He may thus deny that the 
 perception of the external world is really immediate, while 
 admitting the veracity of all the original deliverances of con- 
 sciousness. Hamilton does not appear to have paid sufficient 
 attention to the views of these philosophers, which, if accepted, 
 would very much weaken the force of his appeals to popular 
 belief and to the confessions of adversaries, as well as to the 
 individual consciousness of his reader or bearer. He believed, 
 however, that he had reliable tests for distinguishing between 
 the original and acquired elements of consciousness, the most 
 prominent of these being the test of necessity. Wlien I 
 pressed my hand against the table, for instance, the convic- 
 tion that the table was there, and that I perceived it, forced 
 itself upon me with an irresistible necessitj' that proved the 
 original and intuitive character of the perception. The value 
 of this test will be touched on hereafter. It is enough for 
 the present to say that nianj' philosophers maintain that such 
 a necessity may be generated by association of ideas in cases 
 where there was no original necessity, and consequently the 
 positive portion of Hamilton's argument cannot at present be 
 accepted as conclusive. The question would probably have 
 been dealt with more fully if Hamilton bad lived to complete 
 his system, for in his sketch of a preface to his edition to 
 Keid, he writes : " An element of thought being found 
 necessary, there remains a fnither process to ascertain whether 
 
NATURAL REALISM. 39 
 
 it be, 1st, by nature or education; 2nd, ultimately or deriva- 
 tively necessary ; 3rd, positive or negative/' ' But it cannot be 
 said that such an inquiry actually carried out is to be met with 
 in his writings, except as regards the third of these questions. 
 Hamilton also argues that a consciousness of a mental opera- 
 tion involves a consciousness of its object, and that since we are 
 conscious of the act of perception, we must be conscious of the 
 object of that act ; ^ and that, iu fact, since the consciousness 
 of a relative involves that of its correlative, the consciousness 
 of the ego (as such) implies a consciousness of the non-ego.' 
 This argument, however, must be taken in connexion with 
 bis distinction between immediate and mediate knowledge, 
 which on more than one occasions he developes at considerable 
 length, but which is briefly given in his definitions of them. 
 "They are," says he, " thus defined. Intuitive or immediate 
 knowledge is that in which there is only one object, and in 
 which that object is known in itself, or as existing. Repre- 
 sentative or mediate knowledge, on the contrary, is that in 
 which there are two objects — an immediate object and 
 a mediate object — the immediate object, or that known 
 in itself, being a mere subjective or mental mode, relative 
 to and representing a reality beyond the sphere of con- 
 sciousness — the mediate object is that reality thus supposed 
 and represented,'" * It is plain from this extract, as well as 
 many other passages, that when the doctrine that con- 
 sciousness of the operation implies consciousness of its object 
 
 ' field, p. xviii. 2 j^g^^; \ 2II, seq. 
 
 ^ Lect. i. 225. This was the argument by which Cousin sought to 
 prove that we are conscious of the Infinite. We are admittedly con- 
 scious ol' the finite, hut cannot be conscious of one relative without the 
 otiiei'. This reasoning, however, Hamilton there rejects. (Discussions, 
 p. 18.) But the non-ego is not, in Hamilton's opinion, a mere negative 
 like the Infinite. 
 
 * Lect. ii. 87-8. 
 
40 SIR WILLIAM HAMILTON. 
 
 is applied to our mediate or representative knowledg'e, where 
 there are two objects^ it must be understood of one of these 
 objects only — namely, of what Hamilton calls the immediate 
 object, to the exclusion of what be terms the mediate 
 object. But in applying- it to our immediate knowledgCj 
 where there is but a single object, no such difficulty or 
 ambiguity arises. The correct mode of expressing the doc- 
 trine wonldj in fact, be that the consciousness of an operation 
 implies the consciousness of its immediate object.' As thus 
 explained, however, Hamilton''s argument seems to beg- the 
 question, for the Cosmothetic Idealist would deny that the 
 external object is the immediate object of the mental opera- 
 tion known as perception. But Hamilton, in the passages 
 referred to, is merely engaged in refuting Eeid and Stewart. 
 These philosophers had denied that we are conscious of the 
 
 ' Mr. Mill understands Hamilton as applj'ing this doctrine to the 
 mediate object of our representative or mediate knowledge, or rather he 
 seems to take it for granted that this is the only thing that Hamilton 
 could have meant by the term " object," when used in connexion with 
 mediate or representative knowledge. He has, of course, no difficulty in 
 showing that the doctrine, so understood, is erroneous. {Examination of 
 Hamilton, p. 150, seq.) The doctrine in question was no doubt intended 
 by Hamilton to apply to belief as well as to knowledge ; but in mediate 
 belief, as in mediate knowledge, the only object of which we are conscious 
 is the immediate object- — the subject-object. This non-recognition of 
 the distinction between the immediate and the mediate object — the 
 subject-object and the object-object — has led Mr. Mill in an other error. 
 He alleges {'Examination, pp. 223-4) that Hamilton confessed that the 
 distinction which consciousness draws between the ego and the non-ego 
 is sometimes a mistake, and cites a passage in which Hamilton states 
 that in all cognition there is an object (Lect. ii. 432), as an assertion 
 that we sometimes regard modes of self "as external and a non-eo-o." 
 The very words quoted by Mr. Mill ought to have shown him that Hamilton 
 was only speaking of the subject-object — of a mode of the ego which 
 consciousness distinguishes " as an a ccic^eni, from the ego as the siittjertoi 
 that accident.'' 
 
NATURAL REALISM. 41 
 
 external object, while at the same time they seem to have 
 admitted that the external object is the immediate object of the 
 act of perception. If so, the argument is good as against 
 them, and it was not perhaps intended to be applied generally. 
 The negative portion of Hamilton's argument is mainly 
 directed against the class of philosophers whom he designates 
 Hypothetical Realists, or Cosmothetic Idealists — namely, 
 those who affirmed the existence of the external world, while 
 denying the immediate perception of it — a class in which, 
 among others. Dr. Brown must undoubtedly be placed. The 
 main scope of Hamilton's argument against these philosophers 
 is to prove that they had no right to believe in an external 
 world at all, and this I think he must be regarded as having 
 established. Some of his reasonings are, no doubt, open to 
 exception. He assumes that they all admitted that conscious- 
 ness testified that our perception of the external world was 
 immediate or intuitive, but denied that this testimony was 
 veracious; and he enlarges at considerable length on the 
 absurdity of denying the veracity of consciousness, or of 
 alleging that some of its utterances are true and others false, 
 and endeavouring to discriminate between them. Against 
 Brown, he insists on the special absurdity of which that 
 philosopher was guilty in accepting the existence of the 
 external world merely on account of our natural belief in its 
 existence, while denying the truth of our natural belief in the 
 immediate perception of it — which perception, or supposed 
 perception, is in reality our only reason for believing that it 
 exists. Again, since the Cosmothetic Idealists deny that wi' 
 have an immediate or intuitive knowledge of matter, they are 
 bound to maintain that our knowledge of it is mediate or 
 representative; but in opposing this doctrine Hamilton seems 
 to me sometimes to play on the words "representative" and 
 " representation ; " as, for instance, when he calls on the 
 
42 SIR WILLIAM HAMILTON. 
 
 Cosmothetie Idealists to prove that their representation is lilee 
 the object — that it truly represents it. This argument is 
 hardly applicable, at all events, to philosophers who main- 
 tained, with Brown, that the only relation between the (so- 
 called) representation and the object is that of cause and 
 effect, the object being the unknown cause of the represen- 
 tation, or rather mental modification j and on this ground 
 Mr. Mill vindicates Brown against a considerable part of 
 Hamilton's criticism. With more force Hamilton insists that 
 all representation presupposes a presentation — that all mediate 
 knowledge presupposes an immediate knowledge upon which 
 it rests — but that, as perception is the faculty by which we 
 acquire o\x\ first knowledge of the external world, it cannot 
 suppose a previous knowledge as its condition.' But even 
 here Brown could reply that the so-called perception of the 
 external world consisted in nothing but inferring a cause for 
 our sensations, and that the idea of cause being either a 
 priori or attainable by means of internal consciousness, no 
 special faculty of External Perception was necessary in order 
 to acquire it. If, however, Hamilton has not dealt with this 
 doctrine of Perception by means of the Principle of Causality 
 as fully as we might have expected, he has left us in no doubt 
 of his opinions upon the subject. As already remarked, even 
 assuming that the cause of our sensations cannot be our own 
 
 ' Lect ii. 106. Tlie passage is strangel3' misunderstood by Mr. Mill 
 {Examination of Hamilton, p. 204, 4th edit.). He understands Hamilton 
 as stating, tbat we cannot recognize a mental modification as representa- 
 tive of something else, unless we have a prc-ient knowledge of that some- 
 thing else otherwise obtained ; which is, of course, inconsistent with the 
 fact of memory as well as with Sir William Hamilton's description of it. 
 But Hamilton's doctrine is not that I cannot know a picture to be like the 
 original, unless I have a present knowledge of the original otherwise 
 acquired, but n)erel3'- that I could not recognize the likeness unless I had 
 
 at some time or other seen the original. This seems almost a truism. See 
 
 further, Reid, 811 (a). 
 
NATURAL REALISM. 43 
 
 minds, it may be God or some other spirit ; ' and therefore this 
 Principle of Causality (assuming its validity) leads to no 
 external world. Nor is the matter much mended by em- 
 ploying the phrase the external cause of our sensations. II 
 by " external " in this phrase is only meant independent of 
 our own minds, God or any other spirit is external iu this 
 sense. If by "external cause" is meant the cause of my 
 feeling or perception of externality, there is no reason why 
 that particular feeling or perception should not be produced 
 in me by the agency of God or of some other mind, as well as 
 anj' other feeling. But if by " external cause" is meant a 
 cause existing in space, the question whether such a cause 
 constitutes a veritable external world will depend on the view 
 which we take of the nature of space. If space is purely 
 mental — if it is a mere feeling or state of the mind which 
 perceives or represents it — a cause existing iu space is merely 
 a cause existing in the mind or minds wherein the idea or 
 representation of space is found ; while, if space is something 
 independent of my own or of any other mind, a cause of my 
 sensations existing in space must be regarded as likewise 
 independent of them. But the Principle of Causality, which 
 merely refers our sensations to some cause or other, cannot in- 
 form us whether this unknown cause exists in space or not. 
 For that purpose we require some further evidence, and it is 
 not easy to see what that otber evidence can be, unless we are 
 in some manner informed of the fact by direct perception. 
 
 It is, perhaps, too early to form a correct estimate of the 
 value of the doctrine of Natural Realism which Sir William 
 Hamilton has thus bequeathed to philosophy; but it will, I 
 believe^ be confessed by the most competent judges that he has 
 
 ' He even asserts in one passage that it must be God or some 
 other spirit (Lect. ii. 142); hut a few pages earlier (Lect. ii. 120), he 
 admitted the contrary. 
 
44 SIR WILLIAM HAMIL TON. 
 
 logically extinguished Cosmotbetic Idealism, and established 
 that, in his own language, " Natural Realism and Absolute 
 Idealism are the only systems worthy of a philosopher." ' 
 He recognizes, however, certain other Theories of Perception 
 of which it may be desirable to give a short account. There 
 is first Nihilism, which denies the absolute or independent 
 existence either of mind or of matter. If this theory merely 
 denies that either mind or matter exist as siibstances, it is 
 hardly correct to call it a theory of perception ; for Hamilton 
 admits that in perception we do not cognize the substances 
 either of mind or of matter, but only their attributes or 
 phenomena Nihilism is indeed a theory concerning the 
 nature of the thing or things perceived, but it is not a theory 
 as to what is revealed in the act of perception, and therefore 
 should not, I think, be classed with Natural Realism and 
 Absolute Idealism as a theory of perception. A similar 
 observation applies to the next system in Hamilton's list — 
 that of Absolute Identity. This system maintains that the 
 ego and the non-ego which we cognize in every act of per- 
 ception, are both modifications of the same ultimate substance, 
 which is not properly designated either mind or matter. 
 The advocates of this theory can hardl}' maintain that this 
 identity of the two substances is revealed in the act of per- 
 ception itself, and therefore this theory, like Nihilism, relates 
 to the conclusions which we form concerning the nature of the 
 ego and the non-ego on some other ground than the mere 
 act of sensitive perception.' Lastly, there is Materialism. 
 Here I should state that Natural Realism, as Sir William 
 
 » Reid, 817, note. 
 
 ^ Cousin is mentioned b}' Hamilton as one of tlie ablest advocates of 
 this view. But he arrives at the estei-nal world by the operation of 
 the Principle of Causality in referring our sensations to unknown causes, 
 and is therefore, so far as the process of perception is concerned, a Cos- 
 mothetic Idealist. 
 
NATURAL REALISM. 45 
 
 Hamilton propounded it, asserts something more than the 
 direct intuitive perception of the external world. It also 
 asserts that the material object thus immediately perceived is 
 distinct from, and independent of, the mind or ego ; for which 
 reason he sometimes calls his system Natural Dualism, he- 
 cause it asserts at least two ultimate existences — mind and 
 matter — ego and non-ego. Hence a materialist who be- 
 lieves in an immediate perception of the external world is 
 not regarded by Sir William Hamilton as a Natural Realist, 
 but placed in a separate class. It would, perhaps, have been 
 better to have extended the meaning of the phrase Natural 
 Realist so as to include all who believe in an immediate per- 
 ception of the external world (in the sense already explained), 
 whether Materialists or Spiritualists. Matt'^r is not one 
 thing, but a number of things in many respects dissimilar to 
 each other in their properties, and if the perceived non-ego 
 be matter, its distinction from the ego seems sufficiently 
 preserved, provided the ego is regarded as other matter. In 
 tlie same way the Idealist can preserve the distinction be- 
 tween the ego and the non-ego intact by maintaining that 
 the non-ego is another mind. Materialists who believe in 
 an immediate perception of the external world would thus 
 seem to be in truth Natural Realists, while those Materialists 
 who deny that immediate perception should be classed as 
 Cosmothetic Idealists. Cosmothetic Idealism again has, ac- 
 cording to Hamilton, two principal forms (which he sometimes 
 expands to three), viz. that which holds that the representa- 
 tive object — which on that theory is the object immediately 
 known in perception — is a modification of mind, and that 
 which denies it to be so. But those philosophers who held 
 that the representative object was not a modification of mind, 
 maintained that it was a modification of matter, situated in the 
 brain or other sensorimn. Such a doctrine belongs not to 
 
46 S/R WILLIAM HAMILTON. 
 
 Cosmothetic Idealism, but to Natural Realism ; for Hamilton 
 hiiQself, as we have seen, thinks it sufficient if we have an 
 immediate perception of the nerve-extremities which terminate 
 in the brain, and holds that, if we have a direct consciousness 
 of any portion of the material world, it is of no consequence 
 whether that portion is larger or smallei'.' The philosophers 
 in question may have been mistaken in holding that the 
 objects in the brain which were thus immediately perceived 
 were like the objects in the extra-organic world, and that it 
 was by means of this likeness that we were enabled to pass 
 from tne one to the other. But an erroneous or defective 
 form of Natural Realism is one thing, and Cosmothetic 
 [dealism is another. It may be added, that the philosophers 
 to whom I now refer — Demoeritus, Epicurus, and Sir Kenelm 
 Digby, for instance — were confeSFedly Materialists; a fact 
 which indicates that the several Theories of Perception 
 enumerated by Sir William Hamilton are not really distinct 
 from each other. ^ Natural Realism is, when considered by 
 itself, much more akin to Empiricism than to Intellectualism ; 
 and but for the other principles inculcated in Hamilton's 
 philosop)hy, we might have expected that his disciples would 
 have belonged to the a, posteriori rather than the a priori 
 school of philosophers. It is only by the assumjition of a 
 two-fold apprehension of space or extension — the one priori, 
 and the other empirical^that Hamilton succeeds in reconciling 
 his Natural Realism with his Intellectualism. The doctrine 
 of Natural Realism, however, is attended with other diflBculties 
 
 ' Possibly, liowever, Hamilton thouglit it essential to Natural Realism, 
 that consciousness should directly attain to a larger or smaller portion of 
 the extra-organic world. If so, the advocates of what he rails " the 
 cruder form of the representative hj'pothesis," were not Natural Realists. 
 
 2 Accordingly, in an Appendix to his Lectures, Hamilton gives an 
 explanation of the adoption of the representative theory by materialists. 
 Lect. i. 521. 
 
NATURAL REALISM. 47 
 
 whicli Hamilton's followers do not seem hitherto to have 
 efFeeted much towards removing. Some of those relating to 
 the immediate perception of our own organism as extended, 
 are mentioned by Hamilton himself in the note to Reid, p. 
 817, ah'eady referred to ; and indeed, if we have an immediate 
 perception of our own extended nervous organism, it is not 
 easy to explain how there can be any doubt as to the limits 
 and locality of the extension which we immediately perceive. 
 Again, when we endeavour to pass to the extra-organic world, 
 the question arises whether our locomotive faculty, or locomo- 
 tive energy, is known to us as such in the absence of all 
 sensation ? And even assuming that it is, and also that 
 we are conscious that our locomotive energy is resisted, and 
 not resisted by anything in our own organism, does the pro- 
 cess which follows involve anything more than inferring an 
 unknown cause for the resistance which we feel ? If we have 
 a direct perception not merely of the resistance but of the 
 thing that resists, this perception ought to give us some in- 
 formation as to the nature of the thing in question; but 
 Hamilton describes the extra-organic world as merely revealed 
 to us in its character of somethinff that resists and seems to 
 think that all its other qualities are arrived at by inference 
 rather than by direct apprehension. I am far from implying 
 that these difficulties are insuperable, but they seem to me to 
 be worthy of more attention than they have yet received at 
 the hands of his disciples.' 
 
 ' With regard to the extra -organic world I may remark, that parts 
 of our organism may be regarded as an extra-organic world relatively to 
 other parts of it. When the motion of my arm is arrested by bringing 
 it against my leg, it is resisted by something outside the moving portion 
 of my organism, though not outside my organism taken as a whole: and 
 here, on principles of Natural Realism, I may be conscious both of the 
 moving arm and of the leg that resists its motion. This may, perhaps, 
 facilitate the passage from our organism to the extra-organic world. 
 
48 SIP WILLIAM HAMILTON. 
 
 CHAPTER III. 
 
 NECESSARY TRUTHS — THE LAW OF THE CONDITIONED. 
 
 1 NOW pass to Hamiltou's doctrine of Native, Necessary, or 
 a priori Truths, which also is one on which the scientific 
 world is at present divided. He was a firm believer in such 
 truths, and gives us several tests or characteristics, by which 
 they can be distinguished from the products of experience or 
 association. In his edition of Reid he specifies four of these 
 tests, viz. 1. Incomprehensibility. 2. Simplicity. 3. Neces- 
 sity and Absolute Universality. 4. Comparative Evidence 
 and Certainty.' The first of these characteristics would 
 perhaps be better described as Inexplicableness, and the chief 
 use both of it and of the second test is to distinguish the 
 ultimate principles from those derived from them. This, how- 
 ever, is mainly a question of classification. If there are any 
 first principles which are known a priori, and possess perfect 
 certainty, whatever can be logically deduced from them will also 
 be perfectlj' certain and independent of all experience. Hamil- 
 ton sometimes expresses the first of these tests or characteristics 
 by saying that first principles are given to us with a mere 
 belief in their truth," or that they are given to us rather in the 
 form of beliefs than of cognitions ;' for by belief he does not 
 here mean a conviction which falls short of certainty, but a 
 conviction which rests upon itself, and cannot be deduced from 
 
 > Eeid, 75.1 (a). 2 Lect. i. 270. ^ Discussions, p. 86. 
 
NECESSARY TRUTHS. 49 
 
 any other portion of our knowledge.' What is ultimate, 
 simple, inexplicable, must, in this sense of the word, always 
 depend upon mere belief or faith. I am certain — that is, I 
 feel certain — but I can give no reason for my conviction, 
 except that conviction itself. It is, of course, practically as 
 well as theoretically, of importance to distinguish between 
 original and derivative principles ; for Intellectualists will 
 generally admit that the vulgar, and even philosophers, have 
 often ascribed absolute certainty to principles which were not 
 logically deduced from ultimate truths, but also depended in. 
 part on the teachings of experience. But the main question 
 at the present day being whether there are any principles whose 
 truth is known to us independent of experience, we may pass 
 over the first two of Hamilton's tests and proceed to the con- 
 sideration of the third and fourth. The fourth resolves itself 
 into the third. What is universally and necessarily believed 
 must appear to us to be more certain and evident than anything 
 in which our belief is not universal and necessary, and thus 
 universality and necessity come to be the final tests by whicli 
 alone a priori truths can be detected. Hamilton, indeed, 
 on one two occasions seems disposed to make use of a 
 Kantian test, namely, that any notion or principle is a priori, 
 if experience— by which Kant did not mean sensations, but 
 empirical knowledge — would be impossible without it. Thus, 
 according to Kant, the idea of cause is a priori, because 
 without it we could not distinguisli between sensible expe- 
 rience and the illusions of the imagination. If Hamilton 
 recognized this test, however, he mf>kes but a very sparing 
 use of it. His main reliance is on universality and necessity. 
 These tests are applicable both to ideas and to judgments. 
 
 • I do not mean to imply that Hamilton invariably employs the word 
 belief in this signification. The context is usually the best guide to his 
 use of it. See however Lect. iv. 70. 
 
 B 
 
so SIR WILLIAM HAMILTON. 
 
 Tn one sense, indeed, our empirical ideas, when once acquired, 
 become necessary, for we cannot completely obliterate them 
 by any effort of the will. But though I cannot thus finally 
 obliterate the idea of fire, for instance, from my mind, I can 
 imagine all the fires in the universe extinguished. On the 
 other hand I cannot imagine all the space in the universe (or, 
 indeed, any part of it) annihilated. The idea of space thus 
 possesses a necessity which the idea of fire does not ; and this 
 necessity, according' to Sir William Hamilton, affords a proof 
 of its a priori origin, though, as we have seen, he was of 
 opinion that it could also be derived from experience. Again, 
 there are probably some persons in the world who have no 
 idea of fi.re, while there are none who have not the idea of 
 space;' and we can suppose fire to be absent from certain 
 parts of the world, while we cannot suppose a similar absence 
 of space. The idea of space is thus universal in two senses. 
 It is found in every man, and we cannot avoid supposing it 
 to exist throughout the entire universe. It is therefore, 
 according to Sir William Hamilton, a priori. Universality 
 and necessity, indeed, imply each other. A necessary idea, 
 or principle, does not mean one which some individual feels 
 to be necessary, but one which all men feel to be necessary; 
 and that which is strictly and absolutely universal — to which 
 we cannot discover any exception, not only in our expe- 
 rience but even in imagination — is necessary. If we could 
 imagine an exception, it seems almost certain that, by giving 
 free scope to our imagination, we would do so. Therefore if 
 in fact we never imagine an exception, it may fairly be 
 assumed that we cannot. 
 
 Tlie tests are, however, still more obviously applicable to 
 judgments or principles. Take, for instance, the judgment, 
 
 ' This, of course, is intended as an exposition of Sir William Hamilton's 
 
 views, and not an expression of my own opinion. 
 
NECESSARY TRUTHS. 51 
 
 Two right lines cannot enclose a space. All men, perhaps, 
 do not form this judgment, but all men who put together the 
 requisite ideas, believe that the proposition or judgment is 
 true. It is thus universally believed in this sense that all 
 men to whose minds the proposition is present believe it. 
 There is, at all events, no one who (disbelieves it. Again, it 
 is universal in the second sense. We believe it to be true of 
 every pair of right lines, without any exception. And it is 
 necessary; for we cannot, by the utmost effort we are capable 
 of, imagine two right lines enclosing a space. The proposi- 
 tion in question, being thus universal and necessary, is a priori, 
 according to Sir William Hamilton. 
 
 How far this necessit}^, and consequent a priori origin of 
 ideas and of judgments coincides, Hamilton has neglected to 
 inquire. In his discussion on causality, he seems to assume 
 that if the idea of cause is not d priori, the proposition or 
 judgment that whatever begins to exist has a cause (which is 
 known as the Principle of Causality), cannot be so. It does 
 not seem to have occurred to him that if this assumption was 
 true, the Principle of Causality could not be o priori unless 
 the other notion involved in it — that of a beginning of exis- 
 tence — was a priori also. Hamilton, indeed, though aware 
 of the Kantian distinction between Analytical and Synthetical 
 (or Explicative and Ampliative) judgments, would sometimes 
 seem to have adopted an opposite view himself, and to have 
 regarded judgments or propositions as mere analyses of our ideas 
 or notions.' The Principle of Causality would from this point 
 of view be regarded as a mere ana]\'sis of the notion of cause, 
 and the a priori character of both Idea and Principle would 
 rest on the same footing.^ Indeed, iu Hamilton's Tabular 
 
 ■ See Chapter VI. 
 
 ^ In this very discussion, however, he describes the Principle of 
 Causality as synthetical, and says that it cannot he derived from the 
 
 E 2 
 
52 SIR WILLIAM HAMILTON. 
 
 Conspectus of the various Theories of Causation, we must 
 understand his phrase "judgment of causality," ' as sometimes 
 meaning the Idea of Cause, and sometimes the Principle of 
 Causality; and the systems of those philosophers who did 
 not identify the two will fall under at least two of the heads 
 in Hamilton's table. Thus, the system of Reid falls under 
 the second head as regards the Idea of Cause, and under the 
 fifth as regards the Principle of Causality. 
 
 The value of these tests of universality and necessity has 
 since been the subject of much controversy. Some philo- 
 sojjhers have maintained that constant experience and asso- 
 ciation of ideas is sufficient to produce both, while others have 
 denied that any ideas or propositions are in reality universal 
 and necessary. To enter into this controversy would be foreign 
 to the scope of the present work. I will only say that Sir 
 William Hamilton does not seem to have paid much atten- 
 tion to the Association Psychology, and that those who expect 
 to find in his writings a formal refutation of its later deve- 
 lopments will be disappointed. The tests of universality and 
 necessity had long passed current with the greater part of the 
 philosophical world belbre Sir William Hamilton employed 
 them ; and the Associationists themselves are equally ready to 
 appeal to theories which have long passed current, though 
 aware that they are disputed by some — to appeal, for in- 
 stance, to the acquired perceptions of sight, as defined by 
 Berkeley's Theory of Vision, and the secondary desires as 
 described by Hutcheson. Both sides are indeed too much in- 
 clined to accept disputable facts which accord with their own 
 views as established scientific truths, and to expound them as 
 
 Principle of Contradiction for this reason (Leot. ii. 396). His own 
 derivation of it from the law of the Conditioned also implies its synthetical 
 character. Parts of this Lecture, however, were written as late as 1854. 
 ' Lect. ii. 387 ; Di.^^cussions, 613. 
 
NECESSARY TRUTHS. S6 
 
 such to their readers or hearers — especially il' they have 
 in general met with a favourable reception at the hands of 
 philosophers. 
 
 But Hamilton's mode o£ employing the tests of univer- 
 sality and necessity involves something peculiar to himself, 
 and to which he attached no slight importance. He divides 
 mental facts which involve this necessity upon two distinct 
 principles. "There is one necessity/' says he, "when we 
 cannot construe it to our minds as possible that the deliverance 
 of consciousness should not be true. This logiciil impossibility 
 occurs in the case of what are called necessary truths — truths 
 of reason or intelligence — as in the law of Causality, the law 
 of Substance, and still more in the laws of Identity, Contradic- 
 tion, and Excluded Middle. There is another necessity when 
 it is not unthinkable that the deliverance of consciousness 
 may possibly be false, but at the same time when we cannot 
 but admit that this deliverance is of such or such a purport. 
 This is seen in the case of what are called contingent truths, 
 or truths of fact. Thus, for example, I can theoretically sup- 
 pose that the external object I am conscious of in per- 
 ception may be in reality nothing but a mode of mind, or 
 self. I am unable, however, to think that it does not appear 
 to me — that consciousness does not compel me to regard it — 
 as external, as a mode of matter, or not-self. And, such 
 being the case, I cannot practically believe the supposition I 
 am able speculatively to maintain."' Hamilton thus in 
 one sense rests our a posteriori or empirical knowledge, 
 no less than our a priori knowledge, on the necessity 
 of believing it, just as Mr. Herbert Spencer rests it on the 
 inconceivableness of the opposite.' The necessity of the 
 
 > Reid, 754 (b). 
 
 ' Hamilton's test must be regarded as superior to Mr. Spencer's by 
 
54 S/R WILLIAM HAMILTON. 
 
 belief is what distinguishes my perception of the external 
 world from my imagination of it wbeu my senses are inactive. 
 I can represent to myself that this perception is an illusion, 
 and that the entire phsenomenon is a mere dream ; but 
 though I can make this supposition, and maintain it in 
 speculation, I cannot practically believe it. This kind of 
 necessity is a test of an original fact of consciousness — that is 
 to say, an immediate or direct deliverance of consciousness — 
 but it does not prove that the fact is a priori, and arises from 
 the constitution of the mind itself. It rather proves the con- 
 trary : for whatever is necessitated by the very constitution of 
 the thinking faculty must be irreversible in thought. 
 
 But of the necessary truths proper — truths of intelligence, 
 or those which are irreversible in thought — another division 
 has to be made, and one which Sir William Hamilton regards 
 as of such importance that its recognition determines a new 
 era in philosophy.' For the necessity of some principles is of 
 a positive, and of others of a negative, character; and while 
 the former kind of necessity is a test of truth, the latter is far 
 from being so. When a proposition or judgment is positively 
 necessary it is conceivable, while its contradictory opposite 
 is inconceivable. When the necessity is negative, the judg- 
 ment or piroposition, and its contradictory opposite, are both 
 equally inconceivable. Hence the iuconceivableness of the 
 opposite of any proposition is no test of its truth ; for in all eases 
 where the necessity is negative there are two contradictory 
 propositions, both of which are inconceivable, but one or other 
 
 all who admit his distinction between positive and negative necessity. 
 Otherwise the two tests coincide. 
 
 ' Lect. ii. 526-7. See also Lect. ii. 366 ; Eeid, p. 972. Discussions, 
 833. Notwithstandinu; the great importance attached by Sir William 
 Hamilton to this distinction, it is quite overlooked by Mr. Mill in his 
 criticism, and some groundless charges of inconsistency are brought 
 against Hamilton in consequence. 
 
THE LA W OF THE CONDITIONED. 55 
 
 of which, on the Principle of Excluded Middle, must be true. 
 Thus we are unable to conceive that all space is limited, while 
 at the same time infinite space is equally inconceivable. But 
 space, taken as a whole, must be either finite or infinite, and, 
 consequently, one or other of those inconceivable alternatives 
 must be true. The test or criterion of the truth of an a priori 
 principle is thus its own (positive) necessity, and not merely 
 the inconceivahleness of its opposite. " The criterion of truth 
 is the " [positive] " necessity determined by the laws which 
 govern our faculties of knowledge, and the consciousness of 
 this necessity is certainty.^' ' In such a case, I am conscious 
 of the thought as "an act of power — an act of intellectual 
 force ;" whereas, when both alternatives are alike inconceivable, 
 I merely feel a " powerlessness," an " impotence," an " imbe- 
 cility." To this class of positively necessary data of intelligence 
 Hamilton would refer " the notion of Existence and its modi- 
 fications, the principles of Identity and Contradiction and 
 Excluded Middle, and the intuitions of Space and Time ;" ' 
 but, as he adds an " etc.," these are rather to be taken as 
 instances than as an attempt at a complete enumeration. The 
 " positive necessity of so thinking never illudes — is never 
 even the occasion of deception ; but the negative necessity of 
 not so thinking is even naturally the source of deception," ' 
 inasmuch as in our recoil from one inconceivable extreme we 
 are apt to fall into the other, which is equally inconceivable. 
 
 All negatively necessary principles appear to be summed up 
 in the single Law of the Conditioned which Hamilton thus 
 enounces : " All positive thought lies between two extremes 
 neither of which we can conceive as possible, yet as mutual 
 contradictories the one or the other we must recognize as 
 necessary." ■* Inconceivahleness here, of course, affords no 
 
 ' Lect. iv. 69. " Lect. ii. 367. ' Reid, 972 (b). 
 
 * Reid, 911. Similar statements occur elsewhere. 
 
56 SJR WILLIAM HAMILTON. 
 
 test of truth since both the opposed propositions are equally 
 inconceivable ; but we may, notwithstanding', have reasons for 
 believing in the one alternative and rejecting the other. Thus 
 a free action is inconceivable, but it is equally inconceivable 
 that all actions that have ever taken place (whether of God or 
 man) were necessarily determined, which they must have been 
 if there never was a free action. In this exigency the Moral 
 Faculty comes to our aid and turns the scale in favour of free- 
 dom. Hamilton gives numerous examples of the Law of the 
 Conditioned. Thus space must be either finite or infinite, but 
 neither alternative is conceivable. It must be either finite'y 
 or infinitely divisible, but neither alternative is conceivablj. 
 It is the same thing with time. Existence, too, must either 
 have had an absolute commencement or something- must have 
 existed from eternity a parte ante ; but neither of these alter- 
 natives is conceivable. God — the ultimate being — must be 
 either in His own nature absolute (that is, finished, perfected, 
 completed), or He must be infinite ; but it is impossible to con- 
 ceive either. These, moreover, are only examples, and must 
 not be regarded as exhausting' the law among- them. 
 
 This Law of tlie Conditioned has been assailed on various 
 grounds. Sir "William Hamilton's opponents, indeed, have 
 rather dealt with his examples of the law than with the law 
 itself; but a law couched in such general terms can hardly be 
 discussed otherwise than through these examples, and any ob- 
 jections which apply to all the examples alike may be fairlyre- 
 garded as objections to the law itself rather than to the author's 
 illustrations of it. On the other hand, the fact that Hamilton 
 had given one or two bad examples would not militate against 
 the truth of the law, if it was sufficiently vindicated in other 
 instances. The objections referred to ma}', I think, be thus 
 summarized : — 1st. The alleged contradictory opposites are not 
 rfc.,lly contradictory, since a third alternative is admissible 
 
THE LA W OF THE CONDITIONED. 57 
 
 They may therefore be, and, in fact, both of them are, false. 
 This is in substance Kant^s solution of the problems of the 
 finitude or infinity of the universe, of the finite or infinite 
 divisibility of matter, and of freedom and necessity, at least 
 when that problem is propounded in its crudest form. But the 
 Kantian solution assumes the idealistic basis on which the 
 critical philosophy rests, and is not open to a Natural Realist. 
 The question at issue between Kant and Hamilton must there- 
 fore be decided on other grounds. Xndly. It has been denied 
 that the two contradictory opposites are both inconceivable, or 
 at least that they are both inconceivable in the same sense. 
 Thus Mr. Mill thinks it possible to conceive both the finite 
 and the infinite divisibility of space ; and contends that, though 
 we cannot conceive all space as finite, we can conceive it as 
 infinite. Here the controversy turns to a great extent on the 
 meaning which we attach to the word " conceive," and to the 
 corresponding term " inconceivable." That we cannot imagine 
 an infinite space must, 1 think, be conceded ; and it seems 
 equally impossible to picture to ourselves all space as finite. 
 When I imagine a finite space I am, in fact, compelled, as Mr. 
 Mill says, to imagine other space beyond it — I cannot imagine 
 it as constituting the whole of space. Both alternatives, 
 therefore, would here seem to be unimaginable ; and yet if 
 space is anything real (which the Natural Realist must hold 
 it to be) the conclusion that it must be either finite or infinite 
 seems to be inevitable. As regards infinite divisibility, Mr. 
 Mill's idea of it is that of smallness without limit — of a thing 
 smaller than any finite object. I doubt if any such thing is 
 capable of being imagined ; and, indeed, it may be fairly con- 
 tended that our only idea of a smaller than any finite is that 
 of pure nothing, v/hich is clearly unimaginable. On the other 
 hand, when dealing with the conceivableness of a limit to the 
 divisibility of space, Mr. Mill rather attempts to show that. 
 
5 8 SIJ^ J I 'IL L I A M HA MIL TON. 
 
 with a different experience, it might become conceivable 
 than that it actually is so. No one, I believe, can really 
 imagine an indivisible part of space, whether of finite magni- 
 tude or infinitely small, and therefore both alternatives are 
 here also inconceivable — that is, unimaginable. 3rdly. Mr. Mill 
 objects to Hamilton's statement, that all that we can posi- 
 tively conceive lies in the mean between the two inconceivable 
 extremes. This, however, is at best an objection to the lan- 
 guage in which Hamilton expresses the law rather than to the 
 law itself. Space or extension is a thing of which we have in 
 some sense a positive conception, for we can positively conceive 
 a right line, a square, and a circle. But, notwithstanding 
 this positive character of the notion of space, we are unable 
 to conceive it either as finite or as infinite, and yet it must be 
 either one or the other. This is the substance of Hamilton's 
 doctrine concerning space, and he extends it to everything of 
 which we have a positive notion. However positive our notion 
 of a thing may be, we shall, when we endeavour to carry our 
 speculations concerning that thing to the utmost limit, find 
 ourselves placed betwixt two contradictory alternatives, both of 
 which are unthinkable, but one or other of which must be true. 
 This doctrine, I think, Mr. Mill can hardly be said to have 
 shaken. When, indeed, he seeks to derive some of the incon- 
 ceivabilities insisted on by Sir William Hamilton from in- 
 separable association, and not from any original powerlessness 
 or imbecility of the mind, his argument goes to prove that the 
 Law of the Conditioned is not an ultimate mental law ; but 
 this part of the discussion leads us back to a question which I 
 have declined to discuss, viz. whether experience and associa- 
 tion can give rise to necessity, and, consequently, whether 
 necessity can be relied on as a test of ultimate or a priori 
 iruths.' 
 
 ' On this whole question see the 6th Chapter of Mill's Examination of 
 
THE LA W OF THE CONDITIONED. 59 
 
 It is to be observed that it is no part of this theory 
 of the Conditioned that either of the inconceivable alter- 
 natives should be self-contradictory, but rather the reverse. 
 The highest kind of positive necessity, in fact, is that 
 which arises when the opposite alternative is self-contra- 
 dictory. If one alternative was self-contradictory, we could 
 not doubt that the other was the true one; and if both 
 were self-contradictory, it would be equally clear that they 
 were not really alternatives — that they were not mutually con- 
 tradictory propositions, one or other of which must be true. 
 On the contrary, both would evidently be false, and there 
 would of necessity be a third possible contingency in which 
 alone the truth was to be found. When, therefore, Hamilton 
 speaks, for instance, of the Absolute and the Infinite as two 
 contradictory opposites, both of which are inconceivable, he 
 does not mean that either of these opposites is self-contradic- 
 tory; he rather implies that neither of them is so, for other- 
 wise they would not come under his Law of the Conditioned at 
 all. But while a positive notion is verj^ easily distinguished 
 from its contradictory opposite, the distinction is not so easily 
 seen when the notion is negative — that is, inconceivable. In 
 such cases men have sometimes assumed that two notions are 
 compatible when they are really incompatible, and have en- 
 deavoured to get over the difficulty of two inconceivable 
 opposites, one or other of which must be true, by forming a 
 complex notion composed of both. This complex notion is, of 
 course, in reality self-contradictory ; but since both of the con- 
 tradictory elements are inconceivable, the contradiction may 
 for a considerable time escape detection. Thus neither the 
 
 Hamilton. In that work, I may observe, the order in which the different 
 portions of Hamiltonian philosophy is discussed is often objectionable, 
 and seems to betray a misapprehension as to the connexion between the 
 parts of the system. 
 
6o SIR WILLIAM HAMILTON. 
 
 Infinite nor the Absolute, as defined by Hamilton, are self- 
 contradictory notions, though both are inconceivable. But 
 many philosophers have applied to their Deity or Ultimate 
 Being a notion composed of the two ; and this notion is self- 
 contradictory because the notion of the Infinite is contra- 
 dictoi-y to that of the Absolute. But since both the Infinite 
 and the Absolute are inconceivable, the self-contradictory 
 character of the notion which includes the two is often over- 
 looked.' This remark may be useful in correcting misappre- 
 hensions as to the nature of the Law of the Conditioned. 
 In a future chapter Hamilton's doctrine of the Unconditioned 
 will be more fully explained. 
 
 ' This complex notion has no special name, and therefore different philo- 
 sophers have described it as the Infinite, as the Absolute, and even 
 as the Unconditioned. It is not, however, to be confounded with 
 the Unconditioned of Hamilton, which is not a complex notion made 
 up of the Infinite and the Absolute, but a higher and more general 
 notion including both under it. Both are contained in its extension but 
 not in its comprehension. Hamilton no doubt, in one passage, speaks of 
 the Unconditioned as "self-contradictory" on the ground that it includes 
 the two contradictory opposites. Absolute and Infinite (Discussions, p. 17) ; 
 but he is evidently speaking of the Unconditioned of his opponents and 
 not of the Unconditioned as defined by himself. On this whole subject 
 see Chapter V. 
 
CHAPTER IV. 
 
 THE LAW OF CAUSATION. 
 
 One of the best known applications which Hamilton has 
 made of the law of the Conditioned is to explain the Principle 
 of Causality already referred to. This principle he derives 
 from our inability to conceive an absolute commencement. 
 But experience apparently presents us with such absolute 
 commencements. The dew which is deposited on the grass on 
 a fine evening seems to have started suddenly into existence, 
 for uo visible wet of any kind was previously falling. But I 
 cannot conceive it to have absolutely commenced, and there- 
 fore I am driven to conceive it as a thing that previously 
 existed in some other form j for I have the evidence of my 
 senses that it did not previously exist in the form in which I 
 now see it. Accordingly, I find that, as a matter of fact, it 
 previously existed in the form of aqueous vapour diffused 
 through the air ; and this aqueous vapour would thus seem to 
 be the cause of the dew, though, as we shall presently see. Sir 
 William Hamilton did not regard it as constituting the whole 
 cause. The principle, however, has a second branch, which 
 does not seem to have met with a formal expression at the 
 hands of any preceding philosopher. If it is impossible to 
 conceive an absolute commencement of existence, it is equally 
 impossible to conceive an absolute termination. The dew 
 insensibly disappears in the sunshine of the following day ; 
 but I cannot conceive that it has absolutely ceased to exist. 
 I am therefore driven to suppose that it continues to exist. 
 
62 S/R WILLIAM HAMILTON. 
 
 though of course in a different form ; and as a matter of fact I 
 find that it still exists in the shape of aqueous vapour diffused 
 through the surrounding air, and perhaps partially in the sap 
 or juices of the grass. It has thus produced an effect, and 
 this part of the principle may perhaps be expressed — What- 
 ever (apparently) ceases to exist has an effect. 
 
 As thus understood, and limited to the material world, the 
 Principle of Causality would appear to assert nothing more 
 than the permanence or indestructibility of matter. No 
 particle of matter ever begins or ceases to exist in our expe- 
 rience, and when we meet with an apparent commencement or 
 apparent termination of the existence of any material object, 
 we conclude that it is apparent, not real. But Hamilton 
 distinguishes the two principles thus. The principle of the 
 indestructibility of matter depends on the impossibilitj' of 
 conceiving an absolute commencement or termination of 
 existence in Space ; the Principle of Causality on the impos- 
 sibility of conceiving an absolute commencement or termi- 
 nation of existence in Time. The former he designates the 
 Law of Ultimate Incompressibility, because it asserts that, 
 though bodies can be compressed iijto a smaller space than 
 they originally occupied, it is impossible to compress them 
 into no space at all — to extrude them, as Hamilton says, from 
 space. The phrase Ultimate Incompressibility is not perhaps 
 well chosen ; for the Principle asserts that a thing which 
 occupies space can never cease to occupy space (although the 
 space occupied may become greater or less), and has thus no 
 special reference to compression. And, like the Principle of 
 Causality, it has a second branch, namely, that a thing which 
 now occupies space must have done so at every previous 
 instant of time. Solidity, or occupation of space, is thus an 
 essential attribute of body, which we are enabled to ascribe to 
 it independently of all experience. It is not merely that the 
 
THE LA W OF CA USA TION. 63 
 
 thing would not be called body if it ceased to occupy space ; 
 but that, in fact, it can never cease — or, rather, can never be 
 conceived as ceasing — to occupy it.' 
 
 As the Law of Ultimate Incompressibility affirms the 
 impossibility of extruding- from space a thing that once 
 occupies space, so the Law of Causation affirms the impos- 
 sibility cf extruding from time a thing which once appears 
 in time. But, while matter only appears in space, both mind 
 and matter appear in time, and thus the Principle of Causality, 
 or Law of Causation, applies to mind and matter alike. But, 
 notwithstanding this greater extension of the Principle of 
 Causality, it may be asked whether the two principles do not 
 coincide in their application to matter. Would not the 
 impossibility of extruding the dew from space, for 'instance, 
 be sufficient to induce us to look for it in the vapour and sap, 
 after it had dried off the grass, without calling in the Prin- 
 ciple of Causality to our aid ? and, in fact, if it was extruded 
 from space, would it not at the same instant have had its 
 absolute termination in time ? Here, then, it is to be observed 
 that the vapour is not the sole cause of the dew, nor is the 
 dew the sole cause of the subsequent vapour. Cooling was 
 necessary, in the first case, to turn the vapour into dew ; and 
 heating, in the second case, to reconvert the dew into vapour. 
 
 ' But this principle, resting on the inconceivableness of an absolute 
 commencement or absolute termination, and an infinite non-commencement 
 or non-termination being equally inconceivable, we cannot regard it as 
 possessing complete certainty or absolute ti'uth. An absolute commence- 
 ment of material existence may be possible, though we cannot conceive it : 
 and whether existence has absolutely commenced or not, cannot be deter- 
 mined on a priori grounds. Hamilton, however, has never applied the 
 law of Ultimate Inoompressibility to the commencement of material 
 existence, nor indeed to its termination otherwise than by means of com- 
 pression. The observations in the text, wherever they go beyond this, 
 are my own deductions. See also note, p. 81, of the present work, where 
 another view of the law in question is suggested. 
 
64 SIR WILLIAM HA MIL TON. 
 
 But heat and cold are not supposed to be material objects or 
 substances,- to which the Law of Ultimate Incompressibility 
 is applicable ; and therefore that law alone cannot explain how 
 the dew first comes to be deposited, and afterwards dries 
 away. It explains the constancy of the matter, but not the 
 change of form. But then, it will be asked, Can the cold in 
 the one case and the heat in the other be regarded as forms 
 under which the dew or the vapour previously existed ? 
 Hamilton thinks they can. Everything in the preceding 
 instant of time that contributed to the existence of the 
 (apparently) new phseuomenon in the subsequent instant is 
 regarded by him as one of the forms under which that 
 phaenomenon previously existed ; and since the cold as well as 
 the vapour was present at the instant before the dew was 
 deposited, and since the dew would not have been deposited 
 unless both had then co-existed, he regards both the cold and 
 the vapour as forms in which the dew had previously existed. 
 Both occupied the preceding instant of time, though the 
 vapour only can be said to have occupied space; for heat and 
 cold, though they act in space, are not regarded as occupying 
 it. If we take the state of the entire Universe, mental as 
 well as material, at any two successive moments, we shall find 
 a great many phsenomena common to both instants, but also 
 some peculiar to each. The phajnoraena peculiar to the former 
 moment appear to have absolutely terminated ; those peculiar 
 to the latter moment appear to have absolutely commenced. 
 The impossibility of conceiving an absolute commencement or 
 an absolute termination compels us to regard both these appear- 
 ances as deceptive, and we conclude that the phaenomena pecu- 
 liar to the latter moment previously existed, and that the pha3- 
 nnnienapeculiarto the former moment still continue to exist — in 
 other words, thatthe phaenomena peculiarto the former moment 
 are the causes of the phsenomena peculiar to the latter. The 
 
THE LA W OF CA USA TION. 65 
 
 Principle of Causality, as I uiulerstand it, only applies to llie 
 aggregate of peculiar phaenomena in these two* successive 
 moments. To analyze this aggregate into parts, and to 
 pronounce that so much of the peculiar phenomena of the 
 former moment is the cause of so much of the peculiar 
 phenomena of the latter, is the work of experience. Expe- 
 rience alone can inform us of the particular causes of particular 
 effects ; but that every event has a cause, or rather causes, is 
 known d priori.^ 
 
 Thus as the Law of Ultimate Incompressibility asserts the 
 constancy of the quantity of Matter, the Law of Causation 
 asserts the constancy of the quantity of Existence — which 
 Existence may be either material or mental. It is consistent 
 with the transformation of mental into material existence, 
 and vice versa, the former being our notion of creation, and 
 the latter our notion of annihilation. " Form to yourselves," 
 says Sir William Hamilton, " a notion of the universe. Now 
 can you conceive that the quantity of existence, of which that 
 universe is the sum, is either amplified or diminished ? You 
 can conceive the creation of a world as lightly as you can 
 conceive the creation of an atom.^ But what is a creation ? 
 It is not the springing of nothing into something. Far from 
 it. It is conceived, and is by us conceivable, merely as the 
 evolution of a new form of existence by the fiat of the Deity. 
 Let us suppose the very crisis of creation. Can we realize it 
 to ourselves in thought that the moment after the universe 
 came into manifested being, there was a larger complement of 
 existence in the universe and its author together than there 
 was the moment before in the Deity himself alone ? This we 
 
 ' Lect. ii. 408—9. 
 
 * This passage teems to imply that Hamilton did not regard the Law 
 pf Ultimate Incompressibility, as asserting the constancy of the quantity 
 <jl matter in the Universe. See note, p. 81. 
 
 V 
 
66 S/R WILLIAM HAMIL TON. 
 
 cannot imagine. What I have now said of our conceptions oi 
 creation holds true of our conceptions of annihilation. We 
 can conceive no real annihilation — no absolute sinking-of some- 
 thing into nothing. But as creation is cogitable by us only as 
 an exertion of Divine power^ so anuihliation is only to be con- 
 ceived by us as a withdrawal of the Divine support. All that 
 there is now actually of existence in the universe, we conceive 
 as having virtually existed, prior to creation, in the creator; 
 and in imagining the universe to be annihilated by its 
 author, we can only imagine this as the retraction of an out- 
 ward energy into power. All this shows how impossible it is 
 for the human mind to think aught that it thinks, as non- 
 existent, either in time past or in time future." ' /•> nihrlo 
 nihil in nihilum w«7/)0Me r(?!'«'i!j expresses, according to Hamil- 
 ton, " in its purest form the whole intellectual phsenomenon of 
 causality."^ "There is thus conceived," be adds, "an abso- 
 lute tautology between the effect and its causes. We think 
 the causes to contain all that is contained in the effect; the 
 effect to contain nothing which was not contained in the 
 causes."' And after illustrating this by the instances of a 
 neutral salt and of gunpowder, he continues : — " This, then, is 
 the mental phsenomenon of causality — that we necessarily 
 deny in thought that the object which apparently begins to 
 be, really so begins; and that we necessarily identify its 
 present with its past existence."^ Again, "An object is 
 presented to our observation which has phajnomenally begun 
 to be. But we cannot construe it to thought that the object 
 —that is, this delerminale complement of existence — had really 
 no being at any past moment ; because, in that case, once think- 
 ing it as existent, we should again think it as non-existent, 
 which is for us impossible. What then can we — must we — 
 
 ' Lect. ii. 405-6. ' Lect. ii. 377. 
 
 ' Ibid. " Lect. ii. 378. 
 
THE LA W OF CA USA TION. 67 
 
 do ? That the phaenomenou presented to us did, as a plifcnome- 
 non, begin to be — this we know by experience ; but that the 
 elements — the constituents of its existence — only began when 
 the pbsenomenon, which they make up, came into manifested 
 being — this we are wholly unable to think. In these circum- 
 stances how do we proceed ? There is for us only one possible 
 way. We are compelled to believe that the object (that is 
 the certain quale and quantHm of being whose phcenomenal rise 
 into ecsistence we have witnessed) did really exist prior to this 
 rise under other forms (and \>y form, be it observed, I mean 
 any mode of existence conceivable by us or not). But to say 
 that a thing previously existed under other forms is only to 
 say, in other words, that a thing had causes." ' Hamilton, it 
 may be remarked, insists that a thing must have had causes, 
 or that it must have previously existed in other forms, using 
 in both instances the plural number. But it does not appear 
 whether he thought that this was evident a priori, and thus 
 formed a part of the Principle or Law of Causation itself. 
 His examples of causation are usually taken from chemical 
 compounds, where, of course, there being more than one 
 ingredient, the thing did previously exist in different forms 
 rather than in a different form. In popular language it 
 would generally be said that if the thing pre-existed in a 
 different form, there must also be a cause for the change of 
 
 ' Discussions, p. 621. As annihilation is conceived as " the retractation 
 of an outward energy into power," Hamilton regards the quantity of 
 existence in this power and in the outward energy as the same, and the 
 constancy of the quantity of existence in the universe (including the 
 creator) thus hecomes the constancy of the sum of actual and potential 
 existence taken together. " The sum of being (actual and potential) now 
 extant in the mental and material worlds, together with that in their 
 creator, and the sum of being (actual and potential) in the creator alone, 
 before and after these worlds existed, is necessarily thought as precisely 
 iht same " (Lect. ii. 539). This is one of Hamilton's latest writings. 
 
 F 2 
 
68 SIR WILLIAM HAMILTON. 
 
 form ; and as Hamilton regards this cause of the change 
 as one of the forms in which the thing previously existed, it 
 would appear that there must in all cases be at least two such 
 forms. But in this reasoning we are assuming the Principle 
 of Causality, which Hamilton is seeking to define and explain. 
 Probably, if pressed, he would have given the following ex- 
 planation. When a thing is, in popular language, said to 
 change its form, its quantum of existence is always increased 
 or diminished, since if there was no change in the quanluni of 
 existence there could be no change in the thing. But this 
 change in the quantum of existence always implies that some 
 other thing is added to, or taken from, the thing which is 
 said to be changed ; and this other thing must be regarded as 
 one of the forms under which the changed object previously 
 existed. Thus when dew is said to be changed into vapour, 
 there could be no change, if the quantum of existence in the 
 dew and in the vapour was really the same ; but it is not the 
 same, for in changing to vapour the dew has absorbed heat. 
 The quantity of existence in the vapour is not the same as in 
 the dew alone, but the same as in the dew and in the absorbed 
 heat taken together. The dew and the heat, therefore, are 
 equally forms in which the vapour previously existed. If it 
 be conceded that a thing cannot change while the quantity of 
 existence in it remains the same, this reasoning seems to be 
 conclusive. But then the Law of Causation asserts that in 
 the absence of a special interposition by the Creator, the 
 quantity of existence in the universe is constant ; whence, if 
 the foregoing reasoning be correct, it would follow that all 
 change must be regarded as impossible, or rather as mira- 
 culous. The universe cannot change, because to do so the 
 quantity of existence in it must increase or diminish ; and if 
 the universe does not change, nothing in it can do so. 
 
 Such is the Hamiltonian theory of Causation. The Principle 
 
THE LA W OF CA USA TION. 69 
 
 of Causality depends^ according' to him, on our inability to 
 conceive an absolute commencement or an absolute termi- 
 nation ; but this is a mere negative inability, and the counter- 
 hypothesis of an infinite non-commencement, or an infinite 
 non-termination, is equally inconceivable. We have no right, 
 therefore, to regard this law or Principle of Causality as pos- 
 sessing absolute certainty or unconditional truth. It is a prin- 
 ciple which may be either true or false, and we cannot tell 
 which. And, accordingly, when Hamilton insists that abso- 
 lute creation — existence preceded by non-existence — and 
 absolute annihilation — existence followed by non-existence — 
 are alike inconceivable, he takes care to add, " All this may 
 be possible, but of it we cannot think the possibility.'''' ' 
 Indeed, we know that in its full extent the Principle of 
 Causality is not true. A free act is an act which did not pre- 
 exist in other forms; for the temporal antecedents being the 
 same, it may be different. But if we are not directly con- 
 scious of freedom it may be inferred, according to Hamilton, 
 from our Moral Faculty. We ought, therefore we can, was 
 the ai'gument by which Kant established the freedom of the 
 human will. If the Law of Causation possesses a positive 
 necessity, and must consequently be regarded as absolutely 
 true, free-will must be abandoned ; but since it possesses only 
 this negative necessity, and since it is, in fact, equally incon- 
 ceivable that there should never have been at any time 
 a free act by any agent, the Law of Causation must give way 
 to the arguments for human free-will. And it is thus ol 
 real importance to show that this principle does not possess 
 a positive and absolute necessity. For if it did, free-will 
 ■would be impossible, and no arguments in its favour could be 
 entertained ; but when the possibility of freedom is conceded, 
 the question of free-will or necessity is to be decided by the 
 » Lect. ii. 400. 
 
•JO SIR WILLIAM HAMILTOA 
 
 evidence which can be adduced in favour of either alterna- 
 tive.' 
 
 Some of the objections that have been urged against this 
 theory of causation disappear as soon as its uncertain and 
 negative' character is adverted to. Thus, when Hamilton 
 describes the effect and its causes as the same thing in diffe- 
 rent formSj and speaks of the quantity of existence in the 
 creator and the universe together as identical with that which 
 previously existed in the creator alone, he has been accused of 
 favouring Pantheism. But what Hamilton says is that this 
 is our way of conceiving creation, but that we have no way of 
 knowing whether this conception is right or wrong; for our 
 inability to conceive creation otherwise than as " the evolu- 
 tion of a nevf form of existence by the fiat of the Deity,''' does 
 not in the least prove that this was what really took place 
 when the universe was created. In fact, we know the prin- 
 ciple to be untrue in the case of human free-will, and must, 
 therefore, accept its other applications with great reserve and 
 caution. Again, he has been accused of confounding actual 
 with potential existence ; but the utmost that can be deduced 
 from his expressions is that we conceive them as identical, and 
 not that they are so in fact. And, if we bear in mind what 
 Hamilton means by potential existence, there seems to be 
 little ground for quarrelling with this part of his doctrine. 
 A boy has sometimes been said to be potentially a mathe- 
 matician, provided that by proper instruction r nd application 
 he may become one. But this is not the kind of potential 
 existence of which Hamilton is speaking. The forms under 
 which the mathematician previously existed are not, in his 
 
 ' Hamilton makes no reference to the evidence wliich experience affords 
 in favour of the system of 'Necessity, or rather of Determinism. He 
 deals only with those philosophers who, regarding the Law of Causation 
 as an absolute truth, independent of expeiience, had applied it to prove 
 that the freedom of the will is impossible. 
 
THE LA W OF CA USA TION. yi 
 
 opinion, simply the boy, but also the instruction and applica- 
 tion — everything, in short, that was necessary for his becoming 
 a mathematician ; and what Ham.ilton says is, that the quan- 
 tity of existence in the mathematician is conceived as identical 
 with the quantity of existence in the boy, and in all the 
 conditions requisite for his becoming a mathematician taken 
 together. All things requisite to produce a phsenomenon are 
 on this theory regarded, when taken collectively, as possessing 
 the same quantity of existence with the phasnomenon itself; 
 and the phsenomenon thus produced is regarded as potentially 
 existing in the sum of all these requisites.' Such at least 
 appears to be his general doctrine, though in speaking ot 
 creation he describes the universe as pre-existing in the 
 Divine creative power, and not in that power together with 
 the determination to exert it.'' Even here, however, some- 
 thing may be said in favour of the theory. When God 
 creates any particular thing, which we may call A, He 
 deprives Himself of the power of creating that thing. He 
 
 * But if some of the requisites remain, the total phsenomenon produced 
 must not be regarded as the new phsenomenon only, but the new pha>no- 
 menon together with such of the requisites as continue to exist unaltered. 
 The quantity of existence in the sura of the requisites is thus conceived as 
 identical with the quantity of existence in the continuing requisites, and 
 in the new phsenomenon taken together. 
 
 ^ I suppose because he regarded the determination to create as free. 
 But a free act being iuconsistent with the Law of Causation, as defined by 
 Hamilton, he ought to have maintained that the Divine volition to create 
 ■was conceived by us as necessarily determined ; and that this volition (oi 
 rather the conditions which determined it) must be included among the 
 forms in which the universe is conceived to have existed previous to the 
 creation. It is with reference to the necessity of more than one thing 
 concurring to produce any effect that Hamilton says, " I speak only of 
 second causes. Of the causation of the Deity we can form no possible 
 conception " (Lect. ii. 408) ; but the observation seems to me hardly 
 consistent with his statements regarding the mode in which we conceive 
 creation and annihilation. 
 
SIR WILLIAM HAMILTON. 
 
 can create another thing exactly like it, which we may call 
 B, but His power of creating B equally existed before He 
 created A, and has not been in any way enlarged by that 
 creation. It would thus seem as if every act of creation must 
 be regarded as lessening the power to create to an extent 
 commensurate with the creative act. But the Hamiltonian 
 theory of causation is perhaps objectionable on a different 
 ground. The Divine power is generally believed to be infi- 
 nite, and as Hamilton admits that infinite power is incon- 
 ceivable, we cannot conceive the sum of existence — that is of 
 power, in the Deity— at the instant before the creation, in 
 order to compare it with the sum of existence in the Dtity 
 and the universe combined immediately afterwards. And if 
 infinite power, or an infinite quantity of existence was con- 
 ceivable, it would probably be regarded as unsusceptible of 
 increase or diminution by the addition or subtraction of finite 
 quantities, and might therefore be regarded as identical after an 
 absolutely new finite quantity of existence had been added to it. 
 If so, the constancy of the quantity of existence — that quantity 
 being supposed infinite — would not exclude the absolute com- 
 mencement or absolute termination of the existence of finite 
 objects. To this Hamilton would probably reply that, though 
 the quantity of existence in the Deity and the universe, taten 
 together, may really be infinite, it is necessarily conceived by 
 us as finite. And since the Infinite is confessedly inconceiv- 
 able, this must be admitted, provided that the quantity of 
 existence in the universe and the Creator, taken together, is a 
 possible object of human conception. But whether it really 
 is so must be regarded as open to question. 
 
 Thus Dean Mansel denies that we conceive Existence as a 
 quantity at all. We cannot conceive Existence except "in 
 some particular form (this Hamilton would admit), and when 
 so conceived the form is regarded as an cs<ential part of the 
 
THE LA W OF CA USA TION. 73 
 
 existence itself. Who, indeed, would venture to tell us how 
 many minds contain the same quantity of existence with a 
 given portion of the material world? Did the mind of 
 Newton contain only the same quantity of existence with 
 that of an idiot? and are the quantities of existence in a 
 ton of coal and in a ton of gold equal ? Existence in the 
 abstract — existence which is not identified either with matter 
 or with mind — is inconceivable, and cannot, therefore, be con- 
 ceived as having any quantity ; and it is of this abstract 
 existence only that the supposed constancy of quantity can be 
 asserted. I have some doubts as to whether this objection 
 applies to the essentials of the theory, or only to the language 
 in which Sir William Hamilton has expressed it. He was 
 fond of borrowing phrases from mathematics, and often 
 employed them rather inaccurately. That the effect may in 
 some sense be regarded as the equivalent of all the things that 
 concurred in its production would seem to be a natural im- 
 pression. If any of the antecedents had not been present, it 
 would not have occurred, while the popular belief is that when 
 all are present the effect ccw/^ not but have followed. There is 
 thus a mutual equivalence between the effect and the sum- 
 total of its causes or conditions; and the statement that the 
 complement or quantity of existence in both is identical may 
 be only an inaccurate way of expressing this equivalence. 
 But I confess that I have not been able to put the Hamil- 
 tonian theory of causation into language which will evade 
 Dean Hansel's objection, while, at the same time, preserving 
 its essentials intact. 
 
 Again, it has been objected that Hamilton's theory only 
 takes notice of what Aristotle designated the material cause, 
 and passes over the efficient cause, which is the very thing to 
 which the term " cause " is exclusively appropriated by the 
 vulgar. This objection is, I think,- groundless. Hamilton 
 
74 SIR WILLIAM HAMILTON. 
 
 includes the efficient cause among the forms under which the 
 phaenomenon previously existed. Thus, in the case of vapour, 
 already considered, he distinctly tells us that heat and water 
 are together the causes of the phaenomenon.' It is no doubt 
 a departure from ordinary language to describe the efficient 
 cause of a phsenomencn as one of the forms under which it 
 previously existed ; but if there is no doubt that Hamilton 
 has done so, he cannot, with justice, be accused of neglecting 
 efficient causes. At the same time his theory seems to me to 
 have been mainly suggested by the facts of chemistry, from 
 which his examples are usually selected. A chemical compo- 
 site is identical with the sum of its components, in a sense in 
 which few other effi^cts are identical with the sum of their 
 causes ; and Hamilton sometimes speaks as if the components 
 were the only causes in such cases, overlooking the force which 
 was necessary to bring them together, and combine them. 
 In other passages, however, the necessity of this translating 
 force is recognized. 
 
 It may further be objected that, on this theory, since an 
 absolute commencement and an infinite non-commencement 
 are equally inconceivable, we ought, in addition to the Principle 
 of Causality, to find in the human mind a counter-principle 
 asserting the impossibility of an infinite non-commencement; 
 but no such counter-principle is in fact to be met with. Of 
 this fact Sir William Hamilton gives the following explana- 
 tion : — " As not obtrusive, the Infinite figures far less in the 
 theatre of mind, and exerts a far inferior influence in the 
 modification of thought than the Absolute. It is, in fact, both 
 
 1 Lect. ii. 408. He, curiously enough, adds that there is a third 
 conuause — the atmosphere — the fact being that the presence of the atmo- 
 sphere retards the formation of vapour. He was probably thinkino- of 
 the cloud to which he immediately afterwards refers, rather than of the 
 invisible vapour diflfused through the aii- around us. The air is certainly 
 not a cause of this vapour. 
 
THE LAW OF C A USA TION. 75 
 
 distant and delitescent, and, instead of meeting us at every 
 turn, it requires some exertion on our part to seek it out." ' 
 Conceding tbis, however, the origin of the principle assigned 
 by Sir William Hamilton affords no evidence of its truth, and 
 therefore offers no explanation of the fact that it is so constantly 
 verified in our experience. According to Kant the Principle 
 of Causality is a condition of experience itself. Without it there 
 would be no distinction between experience and dreaming ; 
 and since experience could not exist without the principle, all 
 experience must testify to its truth. With Hamilton, on the 
 contrary, so long as we may remain in the region of pure 
 speculation, the Law of Causation is simply one of two incon- 
 ceivable alternatives, and is not entitled to any preference over 
 the rival hypothesis. Suggested to us by an imbecility or 
 impotence of thought, its sole evidence is, notwithstanding, to 
 be found in experience ; and the origin of the principle, so far 
 from enabling us to anticipate that experience would be found 
 in harmony with it, might even lead us to expect the reverse. 
 And as the Principle thus depends for its evidence on experience, 
 so Hamilton seems more than once disposed to derive the Idea of 
 Cause from the same source. Thus, at the exposition of the 
 two-fold origin of the idea of space in his Lectures, his editors 
 found the marginal jotting, " So Causality :■" ^ nor do I think 
 the oral interpolation which they here add as the explanation 
 (but which, it seems, Hamilton made use of on a different occa- 
 sion, and no doubt in a different connexion) is the true one. 
 " Our internal experience,''' says he, in another place, " espe- 
 cially in the relation of our volitions to their effects may be 
 useful in giving us a clearer notion of causality ; but it is alto- 
 gether incompetent to account for what in it there is of the 
 quality of necessity." ' But neither, I presume, could our 
 
 ^ Discussions, p. 621. ^ Lect. ii. 114, note. 
 
 3 Lect. ii. 392. 
 
;6 S/R WILLIAM HAMILTON. 
 
 external experience account for the quality of necessity which 
 belongs to our idea of space or extension, of which, neverthe- 
 less, Hamilton maintains that we have a direct empirical 
 apprehension ; nor is it easy to see how internal experience 
 could be of use in giving us a clearer notion of causality unless 
 by directly apprehending it. The strongest passage on the 
 subject, however, occurs in one of Hamilton''s notes to Reid, 
 where he says, " the consciousness of our own elficiencj' " [in 
 volition] " illuminates the dark notion oi causality founded, as 
 I conceive, in our impotence to conceive the possibility of an 
 absolute commencement, and raises it from the vague and 
 negative, into the precise and positive, notion of 'power." ' 
 Either, however, he was not constant in his employment of the 
 term "power," or he afterwards altered his opinion ; for we find 
 him almost identifying causality with powerinhislatestwriting 
 on the subject.' Returning to his Notes to Reid, he again 
 alleges that, " for the fact of liberty we have immediately or 
 mediately the evidence of consciousness ; ■" ' but the words 
 " or mediately- " evidently refer to the evidence afforded by 
 the Moral Faculty, and we are thus left in doubt as to whether 
 Hamilton held that we are directly conscious of free volitions. 
 Nor is this doubt cleared up by his unfinished Dissertation on 
 Prescience and Liberty, where he says in a note, " The fiict of 
 liberty may be proved — 1. From the direct consciousness of 
 liberty; see Creuzer/' &C.,'' for he may have merely intended 
 to enumerate the modes in which Libertarians — in particular 
 Creuzer — attempted to prove the fact. In deriving the Idea 
 of Cause from internal experience Hamilton would be involved 
 in the following difficulty. The Principle of Causality, as he 
 explains it, confessedly denies the possibility of an act of free- 
 will. Hence, if we have a direct consciousness of free-will, 
 
 ' Reid, 604, uote. " Lect. ii. 638-9. 
 
 * Eeid, 602, note, see also Lect. i. 33. * Reid, 975, note. 
 
THE LA W OF CA USA TION. 77 
 
 the idea of cause thus derived from internal experience not 
 only does not agree with the a priori notion of cause^ but is 
 actually in conflict with it. If, on the other hand, we derive, 
 from our consciousness of volition, an idea of cause agreeing 
 with the a priori notion, we must be conscious that the will 
 is not free ; in which case the argument for freedom derived 
 from the Moral Faculty becomes unavailing. This was pro- 
 bably the reason why Hamilton never affirmed the two-fold 
 origin of the idea of cause as decidedly as the two-fold origin 
 of the idea of space. But in opposing the theory which 
 asserts that the idea of cause is derived from our conscious- 
 ness of volition, he limits his argument to showing that we 
 have no apprehension of any causal relation between the 
 volition and the subsequent bodily movement. This, he says, 
 is impossible, since there are intermediate agencies of which we 
 are not conscious ; but he leaves untouched the question 
 whether we have not a perception of causal efEeiency in the 
 mental volition itself, merely remarking that this derivation 
 would not account for the necessity which belongs to this 
 notion of cause.' 
 
 That a principle, whose truth is open to so much question 
 as this Law of Causation, cannot legitimately lead us to infer 
 a First Cause seems sufficiently obvious j for even if it was 
 impossible for us to conceive that there was no first or absolute 
 cause, this negative inability to conceive the absence of a 
 thing affords no proof of its presence. And when Hamilton 
 tells us that "the affirmation of a God" is "a regressive 
 inference from the existence of a particular class of effects to 
 
 ' It will be recollected that in describing resistance to wbat he calls 
 the " enorganic volition " to move, Hamilton stated tbat in it I was 
 «onscious of myself as a " force in energy," and of extra-organic matter 
 as a " counter-force in energy." A force in energy is certainly a near 
 approach to the vulgar idea of an eflBcient cause. See Eeid, 866 note. 
 
78 S/R WILLIAM HAMIL TON. 
 
 the existence of a special character of eausej" ' his arg-ument 
 does not turn on a priori, but on a -posteriori considerations. It 
 is only by experience, as Hamilton frequently tells us, that we 
 can know the particular causes of particular effects. " The 
 Deity is not an object of immediate contemplation. We can 
 only know Him mediately through His works, and are only 
 warranted in assuming His existence as a certain kind of cause 
 necessary to account for a certain state of things, of whose 
 reality our faculties are supposed to inform US'" " — these faculties 
 being undoubtedly our faculties of external and internal expe- 
 rience. But, on one occasion, Hamilton seems inclined to em- 
 ploy his Principle of Causality in arriving at the existence of 
 a Deity. In his third Lecture on Metaphysics he describes the 
 process of ascending from causes to their effects, as one which 
 necessarily tends towards simplicity ; for since the causes are 
 always at least two in number, and the effect is identical with 
 the sum of the causes, the effect may be regarded as resolved 
 at each step into at least two elements, each of which must, of 
 course, be simpler than their resultant. His examples are, as 
 usual, taken from chemistry, where at each step in the analysis 
 or decomposition we approach nearer to simple substances. 
 Hamilton seems to have confounded this approach to simplicity 
 with an approach to unity, which in chemistry it certainly is 
 not ; for every material atom or particle must be regarded as a 
 separately existing object, and chemical analysis tends to in- 
 crease rather than to diminish the number of these atoms, 
 since it often shows us that what we took for a single atom is 
 really a composite made up of several atoms differing in kind. 
 This analysis of effects into their causes, however, whether in 
 
 ' Lect. i. 26. This whole Lecture shows tho mistalie which Mr. Mill 
 has made in thinking that Hamilton could have held that the existence 
 of God was known to us by direct consciousness. Examination of 
 Mamilton, p. 169, seq. 
 
 ^ Lect, i. 25. 
 
THE LA W OF CA USA TION. 79 
 
 chemistry or in philosophy in general, can only be carried to a 
 limited extent ; but then, says Hamilton, we neither conceive, 
 nor are we able to conceive^ that the analysis is at an end, and 
 that what we have finally reached is not itself an effect. " We 
 therefore carry on the analysis in imagination ; and as each 
 step in the process carries us from the more complex to the 
 more simple, and consequently nearer to unity, we at last arrive 
 at that unity itself — at that ultimate cause which, as ultimate, 
 cannot be again conceived as an effect. Philosophy thus, as 
 the knowledge of effects in their causes, necessarily tends 
 not towards a plurality of ultimate or first causes but towards 
 one alone. This first cause — the creator — it can indeed never 
 reach as an object of immediate knowledge ; but as the con- 
 vergence towards unity in the ascending series is manifest in 
 so far as that series is within our view, and as it is even im- 
 possible for the mind to suppose the convergence not con- 
 tinuous and complete, it follows — unless all analogy be rejected 
 — unless our intelligence be declared a lie — that we must 
 philosophically believe in that ultimate or primarj' unity 
 which, in our present existence, we are not destined in itself 
 to apprehend." ' This passage I find difficult to reconcile with 
 the more formal expositions of Hamilton's doctrine of causa- 
 tion. The mere negative inability to conceive the series 
 otherwise than as continuous and complete affords no evidence 
 of its real character ; and a positive deliverance of conscious- 
 ness to the effect that the series is in fact continuous and 
 complete would seem to involve a Principle of Causality of a 
 more positive character than that recognized by Hamilton. 
 The argument from analogy can hardly be regarded as con- 
 clusive ; and, indeed, is so evidently dependent on experience 
 that it is rather startling to find it placed in apposition with the 
 words, " unless our intelligence be declared a lie." And the 
 
 ' Lect. i. 60. 
 
So SIR WILLIAM HAMILTON. 
 
 whole passage presents a further difficulty. The causes or 
 elements into which any effect can be resolved by philosophical 
 analysis can never, as Hamilton has just told us, be less than 
 two ; but how could the process of resolving everything we 
 meet with into two elements or causes lead us back to a single 
 cause or element? To trace everything back to the same 
 two causes, seems to be the ne 2)lus ultra of this mode of 
 analysis. When that was done, nothing further could be 
 effected in the way of reducing the ultimate number of causes. 
 By resolving one of the pair into two elements we might in- 
 crease the number of our causes to three, but we could not 
 reduce it to less than two.' 
 
 ' But with the latilude which Sir William Hamilton allows himself in 
 the use of the term cause, and of the phrase " forms of existence," he 
 might perhaps say that the ultimate pair of causes were the Divine 
 power and the Divine determination to exert it. Still, I do not see how 
 the Principle of Causality, as he explains it, can be used to prove the 
 existence of a Deity. 
 
CHAPTER V. 
 
 THE INFINITE AND ABSOLUTE — THE LAW OF SUBSTANCE. 
 
 I NOW proceed to Hamilton's application of his Law of the 
 Conditioned to the possibility of knowing the Absolute or the 
 Infinite, and of forming a system of Rational Theology, that 
 is, a theology based on principles of reason, and independent 
 alike of experience and of revelation. The Absolute and 
 the Infinite are, in fact, the two opposite poles (both incon- 
 ceivable) between which all positive thought lies. Thus, in 
 the case of the Principle of Causality, the two inconceivables 
 were an absolute commencement and an infinite non-com- 
 mencement in time, while with the law of Ultimate Incom- 
 pressibility they were an absolute termination, and an infinite 
 continuance of existence in space.' These, accordingly, were 
 special applications of the notions of the Absolute and the 
 Infinite, which we now come to deal with more generally. 
 The Absolute and the Infinite are included by Hamilton 
 under the common designation of the Unconditioned — a term 
 which he does not define, and which has occasioned some 
 embarrassment to his critic, Mr. Mill. Hamilton, in fact, 
 seems to have used the term " condition," with its various 
 
 ' This principle is not very fully described by Hamilton, and possibly 
 what he intended to assert was that we cannot conceive a material body, 
 either as expanded into an infinitely large, or compressed into an infinitely 
 small, space. In the one case it would be infinitely rare ; in the other 
 infinitely dense. But apart from our experience of expansion and con- 
 traction, would we have conceived a body as changing its bulk at all? 
 
 O 
 
SJR WILLIAM HAMILTON. 
 
 cognates, iu a sort of twofold reference, both of which, how- 
 ever, are justified by common language. Tims we say that 
 one thing is a condition of another, or that one thing is con- 
 ditioned by another, meaning that the two are related, or 
 perhaps specially related by way of causation ; for though a 
 condition is not equivalent to a cause, the cause must be 
 regarded as the sum-total of the conditions.' Again, we say 
 that a thing is in a certain condition, meaning that it is in 
 some particular state or mode — as, for instance, we say that 
 matter can exist in three conditions, the solid, the fluid, and 
 the gaseous. This latter meaning of the word condition — 
 which Mr. Mill does not notice — was, I think, that which 
 was most prominently present to the mind of Sir William 
 Hamilton. "Existence is not cognizable absolutely, and in 
 itself, but only in special modes,"^ would thus seem to be 
 equivalent to the statement that we know not absolute, but 
 only conditioned, existence ; though probably Hamilton would 
 have adduced the other two respects in which our knowledge 
 of existence is immediately afterwards declared to be relative, 
 as affording a further proof, or explanation, of the same state- 
 ment. If I know a thing only in a certain condition, mode, 
 or state, and that thing is capable of existing in other con- 
 ditions, modes, or states, my knowledge of it is not absolute — 
 meaning by absolute " finished, perfected, completed.'' It 
 can hardly be said to be absolute, even if by that term we mean 
 non-relative; but as Hamilton expressly says that these 
 special modes of existence can only be cognized in so far as 
 
 ' To define a cause as " the sum-total of the conditions from which a 
 phEBDomenon unconditionally follows " is tautologous. If the phiEnomenon 
 in question followed from the antecedents conditiounlly, it would only 
 follow when a certain condition (or number of conditions), in addition to 
 these antecedents, was supplied ; in which case the antecedents mentioned 
 could not be the sum-total of its conditions. 
 
 3 Lect. i. 148. 
 
THE INFINITE AND ABSOLUTE. S3 
 
 they are related to our faculties, I need not further discuss this 
 point. The statement that we know nothing but the Condi- 
 tioned, would thus seem to be equivalent to stating that we 
 know existence only in certain special modes related to our 
 faculties.' The Unconditioned will of course be the opposite 
 of this Conditioned. The Conditioned, Hamilton otherwise 
 designates as the conditionally limited, the contradictory of 
 which — the not-eonditionally-limited will evidently include 
 two caseSj viz. the unconditionally limited (or Absolute), and 
 the unconditionally unlimited (or Infinite). I may here 
 remark that when Hamilton contends that thought is only of 
 the conditioned because "to think is to condition/''^ this 
 phrase need not have occasioned any perplexity to Mr. 
 Mill. Hamilton himself explains it immediately afterwards, 
 and in his explanation brings in the two elements already 
 referred to. " Thought," says he, "cannot transcend con- 
 sciousness ; consciousness is only possible under the anti- 
 thesis of a subject and object of thought, known only in 
 correlation, and mutually limiting each other; while, inde- 
 pendently of this, all that we know either of subject or 
 
 ' In the passage of the Lectures already referred to (Lect. i. 148) 
 Hamilton pi-oceeds : — " The modes thus relative to our faculties are 
 presented" (Mr. Mill prints this word "assented") "to, and known hy, 
 the mind only under modifications determined by these faculties them- 
 selves " He can hardly, however, consistently with his Natural Realism, 
 and his defence of the veracity of consciousness, intend to convey that 
 these latter modifications are naturally regarded by us as modifications of 
 the object presented — though of course unreflecting or uncritical minds 
 might easily fall into that error. He does not mean that what is presented 
 to us as object — as non-ego —is really a composite made up of some objec- 
 tive and some subjective elements; but that, along with the presentation 
 of the object, there is always a simultaneous presentation of the subject, 
 the two being mutually related to and limited by each other. Both object 
 and subject are thus known as relative, limited, conditioned, existences. 
 
 ^ Discussions, p. 14. 
 
 G 2 
 
84 SIR WILLIAM HAMILTON. 
 
 object — either of mind or matter — is only a knowledge in 
 each of the particular, of the plural, of the diflferent, of the 
 modified, of tlie phaenomenal." ' 
 
 The Absolute has sometimes been understood in the sense 
 of the non-relative, but that is not the sense in which Hamil- 
 ton employs it in this controversy. The non-relative is, in 
 fact, nearly equivalent to the Unconditioned,' and Hamilton^'s 
 Absolute and Infinite are both equally non-relative, the one 
 being the unconditionally limited, and the other the uncon- 
 ditionally unlimited. Instead of " li'niited," he sometimes 
 uses the terms " finished, perfected, completed," but the 
 meaning is nearly the same. Now it seems to be conceded 
 by nearly all philosophers that there must be an ultimate 
 being'' of some kind, and that this ultimate being cannot, in 
 His own nature, be of the relative and conditioned character 
 which Hamilton ascribes to all the objects of human know- 
 ledge, and of (positive) human thought. Hamilton, accord- 
 ingly, reasons as follows : — We can know and (positively) 
 think nothing but the conditionally limited ; but the ultimate 
 being cannot be the conditionally limited ; therefore, He can- 
 not be an object of knowledge or of positive thought. And 
 after thus laying down bis own theory, he proceeds to deal 
 polemically with the systems which represented the ultimate 
 being as an object of knowledge, of (positive) thought, or of 
 both. We can now see how far Mr. Mill is correct in saying 
 that, in the discussion in question, God is veiled under the 
 abstract names, the Absolute and the Infinite, and, also, how 
 
 ' Discussions, p. 14. 
 
 2 The non-relacive of course means that which is not related to anything. 
 A thing is not absolute in this sense, merely hecause it is not related to us. 
 
 ' Accordingly, Hamilton's Absolute is " that which is out of relation, 
 &c., as finished, perfect, complete, total." Discussions, p. 14, note. 
 
 ^ Or ultimate beings. The question of one or more is not material to 
 the argument at this stage. 
 
THE INFINITE AND ABSOL UTE. 85 
 
 far Dean Mansel is correct in stating that the Absolute and 
 the Infinite were regarded by Hamilton not as predicates of 
 God, but as predicates of a nonentity.' If there be a God, as 
 an ultimate being, He must be unconditioned ; and therefore the 
 question of the cognoseibility of God depends on that of the 
 cognoscibility of the Unconditioned. But unless we are to 
 give the name God to any ultimate being, no matter what 
 its attribute? may be, the Unconditioned is not necessarily 
 God, nor does the cognoscibility of the Unconditioned involve 
 that of the Deity. Persons who are generally (and I think 
 correctly) described as Atheists, have believed in the Uncon- 
 ditioned, and have even founded their so-called Atheism on 
 their peculiar views as to its character. But while God, if 
 He exists, must be identified with the Unconditioned, He 
 cannot, according to Sir William Hamilton, be identified 
 with both the Absolute and the Infinite, since these are con- 
 tradictory opposites. He must be identified with one, and 
 with one only. But then we cannot determine which. The 
 two contradictory opposites stand on the same footing. We 
 have no means of deciding which of them corresponds to the 
 real nature of the Deity, and, consequently. Rational Theology 
 is impossible. Such, I believe, to be the substance of Hamilton's 
 argument; and, if I understand it correctly, Dean Mansel is 
 as much in error in stating that Hamilton did not regard 
 either the Infinite or the Absolute as predicates of the Deity, 
 as Mr. Mill is in assuming that he regarded both of them as 
 such predicates. The very point of his theory — like all other 
 applications of the Law of the Conditioned — is that the Deity 
 must be one of the two, and one only, but that we cannot tell 
 which. Mr. Mill is, perhaps, justified in suggesting that the 
 Deity may be infinite in respect of some attributes, and abso- 
 lute in respect of others ; but, at all events, He cannot be both 
 Examination of Hamilton, p. 45 (4th ed.). 
 
86 S/R WILLIAM HAMILTON. 
 
 absolute and infinite in respect of the same attributes; while 
 He must be either the one or the other.' Either He is 
 limited, without being- limited by anything else, or He is in 
 His very nature unlimited. The only choice is between self- 
 limitation and the absence of all limitation. 
 
 The phrases. The Infinite and The Absolute, seem rather to 
 refer to the existence of the ultimate being than to any par- 
 ticular attributes. But as the Infinite must apparently be in 
 all respects infinite, and the Absolute in all respects absolute, 
 an inquiry into the attributes in which the one (if it exists) is 
 infinite, and in which the other (if it exists) is absolute, may 
 not be out of place. Of course the Absolute cannot be repre- 
 sented as absolute in all attributes positive and negative alike. 
 This would make it, as Mr. Mill says, a fasciculus of contra- 
 dictions, to which no being could correspond as long as the 
 Law of Contradiction is held to be valid. For the same 
 reason, the Infinite cannot be represented as infinite in all 
 attributes, positive and negative alike ; nor does Hamilton 
 ever describe either of these notions in this manner, whatever 
 ground Dean Mansel may have given Mr. Mill for making 
 that charge against him. In fact, negative attributes are 
 only called attributes by a kind of courtesy. When taken in 
 their strict meaning, they imply the absence of some positive 
 attribute : when taken in a looser signification, they imply 
 that it is deficient in quantity. We eanuot speak of an 
 attribute as being infinitely absent ; and though we sometimes 
 speak of its absolute absence, we are not then usiug the word 
 absolute in the sense in which Hamilton employs it in this 
 controversy. We merely mean to convey by the use of the 
 word absolute, that we are using the term absence, with which 
 
 ' That is if the attribute be a positive one. Negative attributes are, in 
 fact, mere names for the absence or deficiencj of positive attributes, aiK? 
 hence cannot be regarded as either absolute or infinite. 
 
THE INFINITE AND ABSOLUTE. 87 
 
 it is joined, in its proper signification, and not in the looser 
 meaning in which it is often employed to imply a great 
 deficiency in quantity. There is no difference between saying 
 that a man escaped " absolutely unhurt," and that he escaped 
 " unhurt," except that the latter form of expression might be 
 deemed consistent with the subsequent statement that he had 
 sustained some very slight degree of pain or injury-^a state- 
 ment which would be inadmissible if the word unhurt was taken 
 in its strict signification. Accordingly, no philosopher, so far 
 as I am aware, ever represented his ultimate being as alike pos- 
 sessed of all attributes, whether positive or negative. The cur- 
 rent idea was that of the ens realissimum,th.e most perfect being, 
 or the sum of all reality — positive attributes being, at this stage 
 of abstraction, identified with reality and perfection, and nega- 
 tive attributes with unreality and imperfection. It was also 
 described as the sum of all possibility ; for when we abstracted 
 from experience, the only test of the possibility of a thing was 
 assumed to be the positive character of our conception of it. 
 This notion of the etis realissimum is fully described in the 
 section of Kant^s Transcendental Dialectic, entitled, " Of the 
 Transcendental Ideal (Prototypon Transeendentale)."' Nor 
 does even Hegel, in the passage cited by Mr. Mill,^ give a 
 different description of the Absolute. " What kind of Abso- 
 lute Being," he asks, " is that which does not contain in itself 
 all that is actual, even evil included ? " The argument here 
 seems to be as follows : — The Absolute Being must con- 
 tain in Himself all that is actual (or positive) ; but evil is actual 
 
 ' See Meiklejohn's Translation of the Critic of Pure Season, p. 352. 
 
 ' Examination of Hamilton, p. 60. The explanation here offered of 
 this passage is equally applicable to the expressions cited by Mr. Mill 
 from Mansel, at p. 118, of his Examination. There is, however, no objec- 
 tion to the Absolute including two contradictory opposites in its extension. 
 What renders a notion inconceivable is the attempt to include two con- 
 tradictory opposites in its comprehension. 
 
88 SIR WILLIAM HAMILTON. 
 
 (oi- positi ve) : therefore, it must be included in our conception of 
 the Absolute Being. Leibnitz would have replied to this, that 
 evil is not anything actual or positive, being only a mere nega- 
 tion or absence of the good; butthis seems to he the only ground 
 on which Hegel's conclusion could be resisted by a philosopher 
 who identified the Deity, or ultimate being, with the ens 
 realissimum. Hamilton was only dealing with the notions of 
 the Absolute and the Infinite which had been advocated by 
 preceding philosophers, and was not in any way bound to 
 combat the phantoms conjured up by Mr. Mill, even if the 
 latter has grammatical usage in his favour.' But if the 
 Absolute and the Infinite need not be absolute and infinite in 
 all attributes whether positive or negative, neither does the 
 notion of a thing absolute or infinite in respect of any one 
 attribute, or in respect of certain attributes only, come up to 
 our ideas of The Absolute or The Infinite. The Absolute and 
 the Infinite are subdivisions of the Unconditioned, and it is 
 not true that everything that is absolute or infinite in some 
 one attribute is unconditioned. Absolutely pure water,' to 
 take an example of Mr. Mill's, is not an unconditioned or 
 ultimate being in any sense. It may not be an object 
 of human cognition, because we may never have expe- 
 
 ' One of the groat defects of Mr. Mill's criticism is, that he so fre- 
 quently endeavours to determine on grammatical or philological grounds 
 what Hamilton and his opponents ought to have meant by the language 
 they employed, instead of seeking to discover in their writings what they 
 really intended to convey. 
 
 ^ Examination of Hamilton, p. 48. But does " absolutely pure 
 water " mean anything more than " pure water " in the strict sense, and 
 not merely in the comparative meaning of water purer than usual ? And 
 is purity itself (at least when employed in relation to water) anything 
 more than the absence of all elements other than oxygen and hydrogen 
 in the proper proportions? If so, the attribute is negative, and absolutely 
 pure water is not a thing which is absolute in respect of any (positive) 
 attribute. 
 
THE INFINITE AND ABSOLUTE. 89 
 
 rienced water which did not contain some impurity, how- 
 ever slight ; nor, perhaps, is it an object of possible cognition, 
 since impurity might exist in such minute quantities as to 
 baffle not only our senses but our finest instruments. But, be 
 this as it may, the possibility of the existence, or of the 
 oognition, of absolutely pure water has nothing to do with 
 the question at issue between M. Cousin and Sir William 
 Hamilton. And whether Cousin would have described his 
 ultimate principle (or Deity) as infinite or absolute in all 
 (positive) attributes or not, he would probably have had no 
 hesitation in describing Him as infinite or absolute in all Ilia 
 attributes. None of the attributes which the ultimate being 
 possessed could be regarded as conditionally limited, and a 
 being which was absolute or infinite in some attributes only, 
 and possessed other attributes in respect of which he was neither 
 absolute nor infinite, could not be regarded as an ultimate 
 being — as the Unconditioned, the Infinite, or the Absolute.' 
 
 ' M. Cousin, who may be presumed to have understood his own theory 
 better than Mr. Mill, never professed to have discovered the paralogisms 
 in Hamilton's Discussion that Mr. Mill detects. On the contrary, he 
 complimented his antagonist on the fairness with which his system had 
 heen expounded and combated. Nor did Hamilton ever maintain that 
 an Absolute Cause was a contradiction in terms. What he contended 
 was, that an Absolute Cause — a thing which existed only as a cause — 
 could not be identified with ilie Absolute. It would, in fact, be in its 
 nature "inchoative and imperfect," and thus contradictory to the Absolute 
 in the sense of the "finished, perfected, completed " (Discussions, p. 35). 
 And when Mr. Mill asks {Examination of Hamilton, -p. 57)," Vf by is 
 M. Cousin under an obligation to think that if the Absolute, or, to speak 
 plainly, if God, is only known to us in the character of a cause, He must 
 exist merely as a cause ? " — he forgets that this is the very question with 
 which Hamilton was pressing his adversary. Cousin apparently had 
 inferred from the fact that God is only known to us in his character of a 
 cause, that, therefore. He existed only in that character — that Absolute 
 Cause was a definition of the Absolute which explained its nature, and 
 might be used as such an explanation in a system of Eational Theologj' — 
 
90 S/R WILLIAM HAMILTON. 
 
 As, granting the existence of an ultimate being, we cannot 
 determine whether He is infinite or absolute, we must, 
 according to Sir William Hamilton, renounce all efforts to 
 obtain a definite knowledge of Him on ajarwn or speculative 
 grounds. He is, in fact, neither an object of knowledge nor 
 of positive thought. But three other opinions on the subject 
 are possible, and, according to Hamilton, have been actually 
 held. Kant was of opinion that the Unconditioned was a positive 
 and necessary thought or idea, but that we had no means of 
 ascertaining whether any Being corresponded to it, and there- 
 fore it remained in our minds as a regulative notion, which 
 failed to convey to us any knowledge of an object. The 
 Unconditioned was therefore, in Kanfs opinion, conceivable, 
 but not cognizable. On the other hand, Schelling maintained 
 that the Unconditioned was not conceivable — that it was not 
 an object of ilionghi — but that we could nevertheless know it 
 immediately by a kind of percejption which he designates 
 Intellectual Intuition ; while Cousin maintained that it was 
 both cognizable and conceivable, and was, in fact, a necessary 
 object both of knowledge and of thought to every member of 
 the human race. Owing to the fact that the Absolute and 
 the Infinite are both inconceivable, most of these philosophers 
 had overlooked, according to Hamilton, that one of these 
 notions was the contradictory of the other, and they in con- 
 sequence employed the terms Unconditioned, Absolute, and 
 Infinite, as if they were all identical in meaning. In ex- 
 pounding Hamilton's philosophj', it is unnecessary to give 
 
 and he had even argued that since God existed only as Absolute Cause, 
 creation was necessary. As to Hamilton's argument on the necessity of 
 creation {Examination of Hamilton, p. 57, note), it seems impossible to 
 conceive that in avoid .time (or rather a time occupied by the Deity alone), 
 a period could arrive at which \i first became better to create than not 
 to create ; but even this would not save M. Cousin's doctrine, which 
 affirms a necessity of creation irrespective of anj' time-conditions. 
 
THE INFINITE AND ABSOL UTE. gi 
 
 his special refutations of Kant^ Sdielling^ and Cousin. His 
 own theory may be correct, even if some of his arguments 
 against his opponents are objectionable; and, on the other 
 hand, these special arguments may in many cases be admitted 
 without accepting the Hamiltonian theory. His main argu- 
 ment, however, against all the advocates of Rational Theology, 
 or rather of Ontology, is thus expressed :— " Those," says he, 
 " who, with M. Cousin, regard the notion of the Unconditioned 
 as a positive and real knowledge of existence in its all- 
 comprehensive unity, and who consequently employ the terms 
 Absolute, Infinite, Unconditioned, as onl}' various expressions 
 for the same identity, are imperatively bound to prove that 
 their One corresponds either with that Unconditioned which 
 we have distinguished as the Absolute, or with that Uncon- 
 ditioned which we have distinguished as the Infinite, or that it 
 includes both, or that it excludes both. This they have not 
 done, and we suspect have never attempted to do."' It will 
 be seen that this argument does not at all turn on the 
 assumption that these philosophers were using the terms 
 Infinite and Absolute in the same sense in which Sir William 
 Hamilton employed them. He rather states the reverse. 
 But having shown that the Unconditioned admits of two 
 subdivisions, which he, for the sake of distinction, calls the 
 Infinite and the Absolute, he challenges them to state under 
 which subdivision their Unconditioned (to which the^ applied 
 the terms Infinite and Absolute) is to be placed. If they 
 cannot do this, Rational or Speculative Theology is, as he 
 believes, extinguished. Our knowledge of God and of the 
 Divine attributes must be derived from experience (external 
 and internal) or from revelation. Hamilton accords no pre- 
 ference to one of these sources over the other. He merely 
 says that the Divine nature cannot be known a priori^ 
 ' Discussions, p. 29. 
 
92 SIR WILLIAM HAMILTON. 
 
 Instead of arguing that the Deity must possess this or that 
 attribute, we must be content to say that we have this or 
 that evidence for believing that He in fact possesses it ; and 
 if the evidence is doubtful or conflicting, we must modify 
 our assent accordingly. 
 
 All this is perfectly consistent with a belief iu the existence 
 of God. The notion of the Unconditioned is not self-con- 
 tradictory, and the want of self-suflSciency in the Conditioned 
 almost drives us to believe that the Unconditioned exists. 
 Neither are the notions of the Absolute, or of the Infinite (as 
 defined by Hamilton) self-contradictory. God may — nay, 
 musi — be either the one or the other; but speculative reason 
 gives us no aid in determining which. I may believe in the 
 existence of a planet in addition to those now recognized by 
 Astronomy, without being able to state its magnitude, its 
 distance from the sun, or the shape and inclination of its 
 orbit. In like manner I may believe in the existence of 
 God without knowing any of His attributes,' or being in a 
 position to construct any science of Theology. And though 
 I identify this Deity with the Unconditioned, a science of 
 Theology is impossible so long as I cannot identify Him with 
 either of those subdivisions which Hamilton designates the 
 Infinite and the Absolute. I might even know the existence 
 of a thing (that is, it might be a necessary deduction from 
 other parts of my knowledge) without being able to construct 
 a science of the thing itself; just as the existence of Neptune 
 was known before that planet was actually discovered. In 
 this last observation, however, I go a step beyond what Sir 
 William Hamilton has expressed ; but the knowledge of the 
 
 ' Except of course the attributes implied in the connotation of the word 
 God, which are not very clearly defined; just as in the other case my 
 belief must extend to all the attributes implied in the connotation, or 
 meaning, of the word planet, but no farther. 
 
THE INFINITE AND ABSOLUTE. 93 
 
 existence of a thing does not seem necessarily to imply the know- 
 ledge of any of its attributes, except those which are implied 
 by its name. Even this exception moreover may be avoided 
 by giving it a name of merely negative import ; which is the 
 case with the names Unconditioned, Infinite, and Absolute. 
 
 All this is so consonant to the spirit of the Experience- 
 philosophy, that we might have expected to find our author 
 safe from attacks on. that side ; and if Empiricists have some- 
 times taken up the cudgels on behalf of the E-ationalists, the 
 explanation seems to be that many of them regard the Deity 
 as an ideal, rather than as a real, being, and are in the habit 
 of placing religious systems higher or lower in the scale, 
 according to what they consider the perfection of their re- 
 spective ideals, rather than according to the evidence for their 
 truth. They thus return to the old ontological notion of 
 the most perfect being (though possibly they would not 
 identify it with the ens realissimum) , not with the view of 
 proving its existence, whether by an analj'sis of the notion 
 itself or by independent evidence, but only for the purpose 
 of using it in Morals as a subjective standard of perfection. 
 Mr. Mill would hardly have penned a well-known passage 
 in his Examination ' (which, however, was written in reference 
 to Mansel, not Hamilton), if he had believed in a really 
 existing God, and a reall}' existing hell ; and his objection to 
 Mansel's doctrine is not that it is disproved either by Natural 
 Theology, or by revelation, but that it is " morally per- 
 nicious." ^ Those who believe that God has bestowed on man 
 a Moral Faculty capable of discerning between right and 
 wrong, may, perhaps, with reason, reject any proposed 
 doctrine on the ground of its moral perniciousness. But 
 whether a theory is morally pernicious or not, is frequently a 
 matter of opinion. Mr. Mill would have strenuously denied 
 
 ' Examination, pp. 128-9. ° BxaminatioD, p. ]13. 
 
94 S/R WILLIAM HAMILTON. 
 
 that the doctrine of Necessarianism or Determinism was 
 "morally pernicious/' but there are not wanting philosophers 
 of eminence who regard that theory as subversive of all true 
 morality. And the days have, I believe, gone by when a 
 mere moral system could be successfully propounded as a 
 religion. In uncultivated ages a great moralist, or a great 
 legislator, was often regarded by his contemporaries or 
 successors as a supernatural being, and his writings were 
 treasured as sacred books. But ancient Greece had attained 
 such a state of civilization as to prevent the works of Epicurus, 
 Zeno, or Aristotle, from being thus regarded, and modern 
 Europe is, in this respect, not inferior to ancient Greece. The 
 propounder of a new religion will, henceforth, have to inform 
 us on what evidence it rests, and if he can afford no other evi- 
 dence of its truth than that its acceptance would be for the 
 benefit of mankind or would cultivate their moral sentiments, 
 I venture to predict that his religion will not meet with general 
 acceptance. Creeds are not among the useful articles that can 
 be made to order. 
 
 There is one passage, however, in the course of this Dis- 
 cussion, in which Hamilton seems to adopt the mode of 
 reasoning afterwards adopted by Mansel, and to contend that 
 the Absolute and the Infinite are inconceivable, because self- 
 contradictory. " The negation of the commencement of 
 time," says he, "involves the afRrmation that an infinite 
 time has, at every moment, already run ; that is, it implies 
 the contradiction that an infinite has been completed. 
 For the same reason we are unable to conceive an infinite 
 progress of time ; while the infinite regress and infinite pro- 
 gress, taken together, involve the triple contradiction of an 
 infinite concluded, of an infinite commencing, and of two in- 
 finites not exclusive of each other."' And amono- his un- 
 ' Discussions, p. 30. See, too, as to the Unconditioned Discussions, p. 17. 
 
THE INFINITE AND ABSOLUTE. 95 
 
 finished posthumous papers we find a list of no less than 
 fifteen " Contradictions proving the Psychological Theory of 
 the Conditioned." ' But in the former passage the context, I 
 thinkj sufiiciently shows what Hamilton intended to convey. 
 "Time," says he, when introducing the subject, "is only 
 the image or the concept of a certain correlation of existences 
 — of existence therefore, pro tanto, as conditioned. It is thus 
 itself only a form of the Conditioned."'^ (The italics are 
 Hamilton's own.) Now, it is natural to suppose that if we 
 take a form of the Conditioned, and attempt to unite it in 
 thought with the idea of the Unconditioned — the Infinite — 
 the result will be the formation of a self- contradictory notion ; 
 but the self-contradiction is not to be found in the notion of the 
 Infinite when taken by itself, but only arises when we endea- 
 vour to join it to the conditioned notion of time. The self- 
 contradiction is not found in the notion of infinity, but in the 
 complex notion of infinite-time. A similar explanation is, I 
 believe, applicable to most of the " Contradictions proving the 
 Psychological Theory of the Conditioned." They are all, or 
 nearly all, contradictions which arise when we endeavour to join 
 the notion of infinity to some other notion, which, according to 
 Hamilton, is in its very nature conditioned. In the Discus- 
 sions, it may be remarked, Hamilton finds this contradiction 
 only in the notion of an infinite, and not in that of an absolute, 
 time; but in the unfinished paper already referred to, the 
 Absolute occurs as well as the Infinite. To represent the 
 notions of the Absolute and the Infinite, as in their own 
 nature self-contradictory, would, as already remarked, be to 
 subvert the Hamiltonian theory in toto. The Law of the 
 Conditioned would, in that case, be inapplicable, and the 
 notions in question would fall under the Law of Contradic- 
 tion, whose necessity, according to Hamilton, is of a positive 
 > Lect. ii. 527-8. ^ Discussions, p. 29. 
 
96 SIR WILLIAM HAMILTON. 
 
 character, and whose truth is, for that reason, indisputable. 
 We are always entitled to affirm of a self-contradictory notion 
 that no real being corresponds to it. 
 
 In expounding Hamilton's views on the Infinite and Ab- 
 solute, we must bear in mind the distinctions drawn with 
 respect to the former in his letter to Dr. Calderwood. "There 
 is," says he, " a fundamental difference between The Infinite 
 (to %.v koX Trail), and a relation to which we may apply the 
 term infinite. Thus time and space must be excluded from 
 the supposed notion of T/ie Infinite, for The Infinite, if posi- 
 tively thought it could be, must be thought as under neither 
 space nor time.-" ' The attempt to unite in thought this 
 notion of The Infinite with that of either space or time might 
 thus be naturally expected to result in a contradiction, though 
 space and time may with truth (or at least without self con- 
 tradiction) be called infinite in the relative sense already alluded 
 to — namely, greater than any finite.^ Again, when Dr. Calder- 
 wood contended that the relative was not incompatible with 
 the Infinite, provided the relation was not restrictive, Hamilton 
 replied, "But restrictive I hold the relative always to be, 
 and therefore incompatible with The Infinite in the more 
 proper signification of the teim though infinity, in a looser 
 
 ' Lect. ii. 531. 
 
 ^ Mr. Mill thinks tlie notion of Infinite too obvious to need ex- 
 planation and yet lie gives two inconsistent definitions of it. At p. 48 
 of his Examination he defines it as " that to the magnitude of which 
 there is no limit." This definition excludes both eternity a 'parte 
 ante, and eternity a parte post, since each of these is limited by the 
 present moment. It likewise excludes the infinitely small. A-ain at p. 62 
 o± Jus J<:.ra,mnation, he defines Infinite (meaning infinitely large; he has 
 a correspond.ng definition of infinitely small at p. 108) as "that which 
 IS g. eater than any given quantity," or " greater than any finite " This 
 
THE INFINITE AND ABSOLUTE. 97 
 
 sense, may be applied to it ; " ' and on the next page he 
 applies the observation specially to space and time, both of 
 which he regards as restrictive. The liijinite is that which 
 is infinite in all relations and respects. It cannot, therefore, 
 have a beginning or an end, and the notions of eternity 
 a parte ante, and eternity a parte post j axe alike inconsistent 
 with it. But these may, notwithstanding, be called infinite 
 in the relative or looser sense of the term, for they are both 
 greater than any finite time. It is only when Infinity is 
 usediu the strict sense, for that which is, in all relations and 
 respects, unlimited, that any conflict arises between the notion 
 of The Infinite and that of Time ; and that a contradiction 
 should arise in this case appears to be consistent, both with 
 the Law of the Conditioned, and with the general system 
 of Sir William Hamilton. Many of the " Contradictions 
 proving the Psychological Theory of the Conditioned " may, 
 I believe, be cleared up by this distinction. 
 
 While I am confident that the foregoing remarks express 
 the views which Sir William Hamilton systematically up- 
 held, there are one or two passages in his writings in which 
 he deals with self-contradictory notions in a less satisfactory 
 manner. Thus, on one occasion, he says, "It is on the 
 inability of the mind to conceive either the ultimate indivi- 
 sibility, or the endless divisibility, of space and time, that 
 the arguments of the Eleatic Zeno against the possibility of 
 motion are founded — arguments which at least show that 
 motion, however certain as a fact, cannot be conceived 
 possible, as it involves a contradiction." ^ With Mr. Mill I 
 am unable to reconcile this passage with Hamilton's repeated 
 assertion of the positive necessity, and absolute truth, of the 
 Law of Contradiction. I do not think he would have had 
 
 1 Lect. ii. 5.32. 
 
 ' Lect. ii. 373. See, too LecD. iv. 71. 
 
98 S/R WILLIAM HA MIL TON. 
 
 recourse to Hansel's device (on a different occasion) of saying 
 that the contradictions were not in the object which we are 
 called on to conceive^ but in our mode of conceiving it. When, 
 this assertion is made with regard to our ideas of the Absolute 
 and Infinite, it seems to expose its advocate to a two-fold re- 
 joinder. First, how do you know that there is any object which 
 you are called upon to conceive? Secondly, even if you are 
 certain that there is a thing of which you are trying to form 
 a conception, why apply to it the name of a self-contradictory 
 conception to which j'ou are well aware that neither it nor 
 any other real thing can correspond ? This reasoning, how- 
 ever, is inapplicable to motion, because motion is admittedly 
 a fact to which our perceptive faculties bear witness. There 
 is, therefore, something to be conceived ; but why, on any 
 principle of the Hamiltonian philosophy, may we not form 
 a conception of that fact without falling into self-contradic- 
 tion ? If we conceive motion as a conditioned — if we avoid 
 thinking of it either as absolute or as infinite — why should 
 we not be able to form as clear and positive a notion of 
 it as of any other fact in our experience ? Hamilton, it will 
 be seen, prefaces the observation on which I am commenting 
 by stating that the arguments of Zeno turned on our inability 
 to conceive either the absolute or the infinite of the divisibi- 
 lity of space. Possibly, therefore, he meant to affirm nothing 
 more than that, although it was certain that motion must be 
 either absolute or infinite in this respect, the absoluto-infiuite 
 of motion was inconceivable, because it included two con- 
 tradictory alternatives. This would indeed be putting a 
 great deal of force on his language, but without placing an 
 unnatural interpretation on the passage I do not see how to 
 reconcile it with his system.' 
 
 ' Ziio's arguments, whatever thtnr value may be, apply only to cou- 
 tinuous motion, and ext)eri^:'oe can never tell us that the motion which 
 
THE LAW OF SUBSTANCE. 99 
 
 The Principle of Substance and Phsenomenon (it will be 
 recollected that with Hamilton these terms are correlatives), 
 or Substance and Accident, is according to our author another 
 application of the Law of the Conditioned ; but his explana- 
 tion of this Principle is given only in one of the unfinished 
 Dissertations to the edition of Reid. It is as follows : — " 1 
 am aware of a phEenomenon — a phenomenon, be it of mind or 
 of matter — that is, I am aware of a certain relative, conse- 
 quently a conditioned, existence. This existence is only 
 anown, and only knowable, as in relation. Mind and matter 
 exist for us only as they are known by us, and they are so 
 known only as they have certain qualities relative to certain 
 faculties of knowledge in us, and we certain faculties of know- 
 ledge relative to certain qualities in them. All our know- 
 ledge of mind and matter is thus relative — that is, conditioned 
 — and so far in conformity with the principle, that we are con- 
 scious only of existence as conditioned. But further. lam 
 aware of a certain phEenomenon, be it of mind or matter. 
 This phsenomenon — a manifestation of what exists for me 
 only as known by me, and of what, as known by me, exists 
 only in relativity to my faculties — how is it that I cannot 
 even conceive it to exist solely in the relativity, in which solely 
 it is known — that I cannot suppose it to be a mere phseno- 
 menon, an appearance of nothing but itself as appearing — 
 but am compelled by a necessity of my nature to think that, 
 out of this relativity, it has an absolute or irrelative existence, 
 i. e. an existence" [which] "as absolute or irrelative" [is] 
 
 we see or feel is absolutely continuous. The sensible effect would be the 
 same if there were alternate moments of motion and rest, provided that 
 these intervals succeeded each other with sufficient rapidity. Achilles 
 might thus pass the tortoise during one of its moments of rest. Even, 
 therefore, were we to admit the reasoning involved in the fallacy of Achilles 
 and the Tortoise, it would not conflict with the fact of motion as revealed 
 by the senses. 
 
 H 2 
 
loo S/R WILLIAM HAMILTON. 
 
 "unknown and incompreliensible ? Why, in short, am I con- 
 strained to suppose that it is the known phsenomenon of an 
 unknown Substance ? Philosophers answer and say, it is an 
 ultimate law of mind. I answer, and say, it is a particular 
 case of the general law which bears" [declares?] "that not 
 only the unconditioned simpl}^, but even the unconditioned of 
 iJie condilioued is unthinkable. Take an object. Strip it by 
 abstraction of all its qualities — of all its pbaenomena— of all its 
 relativities ; reduce it to a mere unconditioned, irrelative, ab- 
 solute, entity— a mere substance — and now try to think this 
 substance. You cannot For either in your attempt to think, 
 you clothe it again wi6h qualities, and thus think it as a 
 conditioned; or you find that it cannot be thought, except 
 as a negation of the thinkable. This is an instance of the 
 unconditioned simply, and an ordinary application of the law. 
 Take now, of the same object, a quality or phsenomenon. A 
 phenomenon is a relative — ergo, a conditioned — ergo, a think- 
 able. But try to think this relative as absolutely relative — 
 this conditioned as unconditionally conditioned — this phano- 
 menon as a phsenomenon and nothing more. You cannot; 
 for either you do not realize it in thought at all, or you sup- 
 pose it to be the phsenomenon of something that does not 
 appear ; you give it a ^asis out of itself ; you think it not 
 as the absolutely, but as the relatively, relative — not as the 
 unconditionall}', but as the conditionally, conditioned — in 
 other words, you conceive it as the Accident of a Subject or 
 Substance. This is an instance of the conditioned, and con- 
 stitutes the special case — the particular law — of Substance and 
 Phsenomenon." " Even absolute relativity, as he elsewhere 
 says, is thus unthinkable. We cannot conceive any given 
 object as consisting solely of relations. We seem compelled 
 to think that it would continue to exist after it ceased to 
 
 ' Reid, 935. 
 
THE LA W OF SUBSTANCE. loi 
 
 stand in any relation to us — that it could exist without being 
 perceived, and even though there was no one to perceive it. 
 But this unperceived existence could only belong to the sub- 
 stratum which is independent of us, since all the qualities of 
 the thing perceived are relative to us. Such seems to be 
 Hamilton's theory of the Law of Substance, which, however, 
 is not very easily reconciled with his Natural Realism. I 
 may add that in one passage at least, Hamilton seems, like 
 Mansel, to affirm that we have a direct perception of our- 
 selves as substances. "As clearly," says he, "as I am con- 
 scious of existing, so clearly am I conscious at every moment 
 of my existence (and never more so than when the most 
 heterogeneous mental modifications are in a state of rapid 
 succession), that the conscious ego is not itself a mere modifi- 
 cation, nor a series of modifications, of any other subject, but 
 that it is itself something different from all its modifications, 
 and a self-subsistent entity." ' He likewise insists more 
 stronglyonthe truth of the Principle of Substance than he would 
 be justified in doing if it is a mere exemplification of the Law 
 of the Conditioned, and thus asserts one of two inconceivable 
 contradictories between which we have no means of deciding.' 
 On the whole he does not appear to have thoroughly worked 
 out this part of his theory ; but his observations may not on 
 that account be less useful as suggestions for future inquirers. 
 
 ' Lect. i. 373. ' See, for instance, Lect. i. 155. 
 
102 SIR WILLIAM HAMILTON. 
 
 CHAPTER VI. 
 
 THE GENERAL PSYCHOLOGY OF HAMILTON. 
 
 Having tbus stated the principal theories of Sir William 
 Hamilton, which may be regarded as original (inasmuch as 
 even where he has been partially anticipated his method of 
 treatment is new), I proceed to give a short sketch of the 
 Hamiltonian Psychology. 
 
 Hamilton adopted the Kantian division of our mental states 
 into Cognitions, Feelings or Emotions, and Conations, as he 
 terms them, including the phajnomena of Desire and Will. 
 Whether it would have been better to have classed the 
 Desires with the Feelings or Emotions, reserving the third of 
 these heads for Volitions only, may perhaps be doubted. 
 Hamilton, however, has written but little on the second of 
 these divisions of the mental phsenomena, and hardly anything 
 on the third, so that his researches may almost be said to 
 have been limited to Cognitions. In treating of any of these 
 classes of mental phsenomena, we may, according to Hamilton, 
 have three objects in view, namely, to investigate the facts 
 themselves, to discover their laws, and to follow them into 
 their results ; and we <hus obtain three branches of Philosojihy, 
 namely, Phsenomenology, Nomology, and Ontology. It 
 seems, however, impossible to separate the study of the facts 
 from that of the laws which govern them, and Hamilton's 
 own Lectures may be regarded as a mixture of what he calls 
 Phsenomenology and Nomology. Ontology he apparently 
 
GENERAL PSYCHOLOGY OF HAMILTON. 103 
 
 regarded as impossible — at least in the old sense — for 
 Hamilton's description of it is wide enough to include 
 Natural Theology when rested on the Design argument and 
 other proofs derived from experience. Of this subject, how- 
 ever, he has not formally treated.' Consciousness is, according 
 to Hamilton, the essential condition alike of the phasnomena 
 of Cognition, Feeling, and Conation. There is no cognition 
 no feeling and no conation of which we are not conscious, and 
 whenever we are conscious, it is always of a cognition, a feeling, 
 or a conation. When we are considering cognitions, feelings, 
 and conations relatively to the conscious mind, we call them 
 states of consciousness : when we wish to treat of them each 
 for itself, we call them cognitions, feelings, or conations, as 
 the case may be. Attention again, according to Hamilton, is 
 nothing more than consciousness, or rather concentrated con- 
 sciousness ; but as in all distinct consciousness there is some 
 degree of concentration, so in all distinct consciousness there 
 is some degree of attention.' Neither consciousness nor 
 attention, therefore, can be referred to any special faculty. 
 They belong to all mental modifications alike, and are common 
 to cognitions, feelings and conations. Man is always con- 
 scious. In the soundest sleep he is dreaming, and if he is 
 unable to recollect his dreams on awaking, it is only because 
 he has forgotten them. In proof of this. Sir William Hamilton 
 relies on several experimental observations ; but perhaps it is 
 also manifest a priori. Consciousness is to the mind what 
 extension is to matter. It is a sort of primary quality, and it 
 is not possible to conceive mind without consciousness. Con- 
 
 ' It is touched on more than once, however. See especially the second 
 of his Lectures on Metaphysics. 
 
 => In a general sketch of this kind I do not think it necessary to give 
 specific references, except when I quote the words of the author. This 
 last statement is taken from Lect. i. 248. 
 
I04 SIR WILLIAM HAMILTON. 
 
 sciousness, however, is only possible through discrimination, 
 and therefore involves afc least two simultaneous objects of 
 perception or thoug-ht ; but it is not limited to two, and is 
 capable of embracing six or seven — not that all these are 
 surveyed with vivacity, but only without absolute confusion. 
 It is, however, as we have already seen, a mistake to limit the 
 province of consciousness to the mind, as most philosophers 
 have hitherto done ; for we may also be conscious of states of 
 matter, and are, in fact, conscious of these in external percep- 
 tion. And this has been admitted by those philosophers who 
 maintained that the idea or representative object of which 
 (according- to them) we are conscious in perception is not a 
 modification of the mind. Consciousness is an immediate 
 knowledge, but it is likewise co-extensive with knowledge in 
 genera], for every act of mediate knowledge is also an act of 
 immediate knowledge. I remember, for instance, that I saw 
 St. Paul's Cathedral yesterday. This is a mediate knowledge 
 of the cathedral ; but it is an immediate knowledge of my 
 present mental representation of the cathedral, and of the 
 judgment or belief that connects the present with the past. 
 In all mediate cognition, as already remarked, there is an 
 immediate as well as a mediate object, and the immediate 
 object is in all cases a present apprehension of consciousness. 
 There is thus no conflict between Hamilton's statement that 
 consciousness is an immediate knowledge, and his other state- 
 ment that it is co-extensive with all knowledge, whether 
 immediate or mediate. It is indeed not only co-extensive 
 with all knowledge, but with all knowledge, feeling and 
 conation; for the feelings or conations would not be mine 
 unless I had an immediate knowledge or perception of them. 
 I cannot know without knowing that I know, feel without 
 knowing that I feel, or will without knowing that I will ■ or 
 vice versa. Our mental acts and the consciousness of them 
 
GENERAL PSYCHOLOGY OF HAMILTON. 105 
 
 are really identical — they are the same things regarded from 
 different points of view. / know, and J know thai I know, 
 are merely two modes of describing the same mental fact or 
 phsenomenon. 
 
 Consciousness, being thus the source and condition of all 
 our knowledge, must be accepted as veracious in every sound 
 system of philosophy. If diffierent portions of our immediate 
 knowledge were found to be in conflict with each other, philo- 
 sophy would be impossible, for we would have no means of 
 determining which was right and which was wrong. Nay, 
 even to affirm that one was wrong would be to affirm the 
 Law of Contradiction, which rests on no higher basis than 
 the veracity of our consciousness ; and to assume that one was 
 right would be to affirm the Law of Excluded Middle, which 
 has the same origin.' In the event of a conflict between an 
 immediate and a mediate cognition, it would be absurd to 
 give the preference to the latter. For, first, every mediate 
 cognition is an immediate cognition ; and, secondly, it repre- 
 sents, or relates to, some other immediate cognition. Thus, in 
 case of my recollection of St. Paul's Cathedral, the present 
 representation in memory is an immediate cognition, and it 
 represents, or relates to, a former immediate cognition, namely, 
 my perception of the cathedral when I saw it last. I cannot 
 set it up as veracious, therefore, without postulating two 
 immediate cognitions, and also a relation between them; for 
 if this relation be unfaithfully depicted, the mediate knowledge 
 in question is likewise unreliable. In connexion with this 
 subject, however, Hamilton draws the following distinction. 
 The facts of consciousness, he tells us, are of two kinds — 
 
 ' Hamilton, however, in practice sometimes seems to ascribe to these 
 principles a higher authority than that which he accords to the ordinary 
 facts of consciousness. This turns on the distinction between two kinds 
 of facts of consciousness to be noticed presently. 
 
io6 SIR WILLIAM HA MIL TON. 
 
 " Fii-st, the facts giveu in the act of consciousness itself; and, 
 second, the facts which consciousness does not at once g'ive, 
 but to the reality of which it only bears evidence. And/' he 
 proceeds, "as simplification is always a matter of importance, 
 we may throw out of account altogether the former class of 
 these facts, for of such no doubt can be or has been enter- 
 tained. It is only the authority of these facts as evidence of 
 something' beyond themselves — that is, only the second class 
 of facts — which become matter of discussion : it is not 
 the reality of consciousness which we have to prove, but its 
 veracity.^' ' 
 
 This distinction is hardly drawn with Sir W. Hamilton's 
 usual precision. Of course, no philosopher can deny generally 
 that there are any facts of consciousness ; but, owing to the 
 difficulty of making careful observations on the mental 
 phsEnomena, there is often a doubt as to whether an alleged 
 fact of consciousness is really such or not. Philosophers are 
 very far from being agreed as to what the facts of conscious- 
 ness are, even if by facts of consciousness we mean those 
 which may now be found in ordinary men ; while the difference 
 is greater if we limit the phrase, " facts of consciousness,'" to 
 those which are original or primitive. Again, from Hamil- 
 ton's language, it might be supposed that the second division 
 referred not to the direct presentations of consciousness, but 
 to something admittedly beyond its sphere, but which it 
 nevertheless in some inexplicable manner suggested, repre- 
 sented, or bore testimony to. In this case, if the perception of 
 the external world is to be referred to the second division — and 
 
 ' Leut. 1. 275-6. Hamilton had expressed the distinction in a less 
 ohjectionable way a few pages earlier. " The facts of consciousness," says 
 he, " are to be considered in two points of view — either as evidencino- their 
 own ideal or phsenoraenal existence, or as evidencing the objective existence 
 of something else bevond them," Lect. i. 271. 
 
GENERAL PSYCHOLOGY OF HAMILTON. 107 
 
 Hamilton undoubtedly meant so to refer it — the doctrine 
 preached would be that of Cosmothetic Idealism, not Natural 
 Realism. Nothing on such a theory \s given in the fact of con- 
 sciousness but the mental state or modification ; but then con- 
 sciousness suggests — represents — bears evidence — that there 
 is a reality beyond that mental state or modification, which 
 may be termed an external world. Probably what Hamilton 
 intended to say was as follows : — The external world, as a 
 thing existing out of and independently of our conscicusness, 
 cannot be regarded as a pari of the facts of consciousness. 
 Though it is presented, not represented, in the fact of con- 
 sciousness, it is possible (without self-contradiction) to admit 
 the fact and yet to deny that the external world really exists ; 
 for why may not presentation be illusive as well as represen- 
 tation ? It may, therefore, be said that the external world is 
 not given — contained — in the facts of consciousness, though 
 it is given — presented — bi/ them. But the language in which 
 Hamilton describes the second class of facts of consciousness 
 still appears objectionable. It is so more especially, if we are 
 conscious of sensation (as Hamilton elsewhere maintains,) not 
 as an affection of the mind alone, but of that composite of 
 mind and matter the animated nervous organism. The state 
 of this organism would in this case appear to be a part of the 
 facts of consciousness themselves, and not something outside 
 them, to which they only bear testimony. The use which 
 Hamilton makes of the distinction between these two classes of 
 facts of consciousness, however, is important. A philosopher 
 may stop at the facts of consciousness considered as mere states 
 of the mind or ego, and refuse to go any farther; but iihe does 
 go any farther, and declares his belief in anything objective or 
 substantial, he thereby accepts the testimony of consciousness 
 to something more than " its own phoenomenal or ideal exist- 
 ence." This testimony is either direct or indirect, but the 
 
io8 S/R WILLIAM HAMILTON. 
 
 indirect depends on the direct, and is inferior to it in point of 
 certainty. The philosopher in question must therefore accept, 
 in part at least, the direct testimony of consciousness, and, 
 accepting it in part, he is bound in consistency to accept it as 
 a whole. Every consistent scheme of philosophy that goes a 
 step beyond Nihilism must accept everything as true that 
 consciousness bears direct testimony to ; and as consciousness 
 bears this direct testimony to the perception and existence of 
 the external world (this, Hamilton thinks, is conceded by his 
 opponents), this testimony must in consistency be accepted 
 as veracious.' Consciousness is to the philosopher what 
 the Bible is to the theologian. As errors in theology have 
 usually arisen from not accepting the testimony, the whole 
 testimony, and nothing but the testimony, of the Bible, so all 
 errors in philosophy have arisen from not accepting the 
 testimony, the whole testimony, and nothing but the testimony, 
 of consciousness ; and as we must appeal to the Bible in cor- 
 rection of the former, so we must appeal to consciousness in 
 correction of the latter. Hamilton has not perhaps taken 
 sufficient notice of the fact that, as the testimony of the Bible 
 is liable to be corrupted by errors of transcription or trans- 
 lation, by interpolations and by the acceptance of apocryphal 
 books as genuine, so the testimony of consciousness is still 
 more liable to be corrupted by similar influences. 
 
 Such is Hamilton's account of Consciousness and Attention. 
 
 ' I cannot think that Hamilton ever intended ia jprove the veracity of 
 consciousness. Consciousness must be accepted as veracious, he says, until 
 we Bee some reason for denying its veracity. If we attempt to represent 
 it as untruthful, we can only do so by making some supposition which 
 seems to carry its improbability on the face of it. One of these sup- 
 positions is that of nature acting not only in vain, but in counter-action of 
 herself. Another is that man is the dupe of a perfidious creator. None 
 of them are of such a character as to commend themselves (in the absence 
 of evidence) to any philosopher. 
 
GENERAL PSYCHOLOGY OF HAMILTON. 109 
 
 As to the relation between Consciousness and Memory, he is 
 less consistent. He begins by laying down in general terms 
 that memory is a condition of all consciousness ; for the notion 
 of ego, or self, which is involved in all consciousness, "arises 
 from the recognized permanence and identity of the thinking 
 subject, in contrast to the recognized succession and variety 
 of its modifications. But this recognition is possible only 
 through memory.'^' This doctrine is not peculiar to Hamil- 
 ton, but it seems open to some objections. Let us go back to 
 the_^«< time that I recognize the permanence and identity of 
 the subject in this succession of its modifications. To recog- 
 nize the two modifications as different and successive, it may 
 be said that I must recollect the former when the latter is 
 present; but in the former there was no ego or self, since by 
 hypothesis that notion arose for the first time on comparing 
 the former (as represented in the memory) with the latter (as 
 actually present) . I was therefore not conscious of the former 
 state, and hence I must recollect that of which I was not 
 conscious when it was present. Again, how could I even 
 inquire whether the subject in these two successive states was 
 identical or otherwise, unless I knew that there was a subject 
 in the former as well as in the latter ; and if there was a subject 
 in the former state, what could that subject be but the ego ? 
 Many philosophers seem to me to have confounded personality 
 with personal identity (which latter cognition, like all other 
 instances of perceived identity, could, as I believe, only arise 
 after we had experienced two states of consciousness, each of 
 which had an ego or person in it), and to have assumed that, 
 previous to the states of consciousness of which the proper 
 expression is " I know," there were other mental states 
 capable of being recollected, which could only be correctly 
 described by some such phrase as " Somebody knows," or 
 ' Lect. i. 205. 
 
no S/J^ WILLIAM HAMILTON. 
 
 " There is knowledge." Apart from the prevalent confusion 
 between personality and personal identity, I see no reason to be- 
 lieve that there ever was such a state ; but it seems doubly incon- 
 sistent for a philosopber who holds that there was such a state, 
 to withhold from it the title of " state of consciousness,''' while 
 at the same time contending that consciousness is the sole 
 field of philosophy. However, even if it were conceded that 
 memory is, in this sense, a condition of all consciousness, it does 
 not follow that every state of consciousness is followed by- 
 memory ; for according to Hamilton, we can be conscious of 
 six or seven objects at once, and if we recollected one of these 
 when we passed into the nest succeeding state of consciousness, 
 it would be sufficient to enable us to represent the two suc- 
 cessive states as successive modes of the same ego or self. 
 Hamilton, however, in some passages affirms in the strongest 
 manner that every act of consciousness is followed by memory, 
 and further that every act of memory is preceded by a state 
 of consciousness — which latter statement I am unable to 
 reconcile with his assertion that memory is a condition of all 
 consciousness, inasmuch as it is only through memory that 
 we attain the notion of ego or self, which is involved in all 
 consciousness. " Of consciousness " says he, " however faint, 
 there must be some memory, however short." " It can easily 
 be shown that the degree of memory is directly in proportion 
 to the degree of consciousness, and consequently that an 
 absolute negation of memory is an absolute negation of 
 consciousness."' Again, "It is a law of mind that the in- 
 tensity of present consciousness determines the vivacity of the 
 
 ' Lect. i. 355. It is curious to lind the editor and successor of Stewart 
 using this Rrgument against that author, without ohserving that Stewart 
 denied that theve was any such relation between consciousness and memory, 
 and founded the doctrine which Hamilton is combating on this denial. See 
 Stewart's Works, ii. 134 (Hamilton's edition). 
 
GENERA L PS YCHOL OG V OF HAMIL TON. 1 1 1 
 
 future memory. Memory and consciousness are thus in the 
 direct ratio of each other. On the one hand^ looking from 
 cause to effect — vivid consciousness, long memory; faint 
 consciousness, short memory ; no consciousness, no memory ; 
 and on the other, looking from effect to cause, long memory 
 vivid consciousness ; short memory, faint consciousness ; no 
 memory, no consciousness." ' But distinct as these declara- 
 tions are, I meet with others of an equally positive character 
 which I am unable to reconcile with them, When combating 
 Locke's theory, that in sound sleep we do not think at all, 
 Hamilton says, " As to the objection of Locke and others, 
 that as we have often no recollection of dreaming, we have 
 therefore never dreamt, it is sufficient to say that the as- 
 sumption in this argument — that consciousness and the 
 recollection of consciousness are convertible — is disproved in 
 the most emphatic way by experience." ^ And he then goes 
 ou to state the facts of somnambulism, of which he says, 
 " we have no recollection when we awake of what has occurred 
 ■during its continuance. Consciousness is thus cut in two; 
 memory does not connect the train of consciousness in the 
 one state with the train of consciousness in the other."' But 
 this '■ forgetfulness is not a decisive criterion of somnam- 
 bulism. Persons whom there is no reason to suspect of this 
 affection, often manifest during sleep the strongest indications 
 of dreaming, and yet when they awaken in the morning retain 
 no memory of what they may have done or said during the 
 night." ^ Moreover something similar to this " rapid oblivion 
 of our sleeping consciousness, happens to us occasionally even 
 when awake. When our mind is not intently occupied with 
 any subject, or more frequently when fatigued, a thought 
 suggests itself. We turn it lazily over and fix our eyes on 
 
 > Lect. i. 368. s Lect. i. 319. 
 
 3 Lect. i. 320. •• Lect. i. 332. 
 
1 1 2 SIR WIL LI AM HA MIL TON. 
 
 vacancy. Interrupted by the question what we are thinking of 
 we attempt to answer, but the thought is gone. We cannot 
 recall it and say that we were thinking of nothing." ' In this 
 last instance perhaps it might be said that there was a very 
 short memory of the thought, and that the faintness of the 
 preceding consciousness accounted for the shortness of the 
 memory. But this explanation is inapplicable to the phaeno- 
 mena of somnambulism, for in that state Hamilton affirms 
 that " the various mental faculties are in a higher degree of 
 power than in the natural," and that we must ascribe to it, 
 " not only consciousness but an exalted consciousness.'" '^ As 
 the passages I have cited are taken from two lectures which 
 Hamilton delivered year after year in immediate succession 
 to the same audiences, it may be assumed that he had some 
 plausible mode of reconciling them, but I have not been able 
 to discover it. If the cases referred to in the 17th lecture are 
 rather instances of very short and very faint memory, than 
 of no memory at all, Stewart might surely be allowed to offer 
 the same explanation of those dealt with in the 18th lecture. 
 
 In connexion with consciousness Hamilton has introduced 
 into English philosophy (though there were not wanting 
 some earlier indications of it) a doctrine of considerable im- 
 portance — that of latent mental modifications, sometimes 
 described as unconscious cerebration. This doctrine may be 
 illustrated by the minima of sense. The minimum visibile is 
 probably not a quantity of space (whether absolute or rela- 
 tive) but a quantity of light. This, however, is not material 
 to the present argument. A field seems to me at a distance 
 to be an uniform green. Coming closer, I see for the first 
 time yellow buttercups and white daisies. Returning to the 
 place from whence it looks an uniform green, it is evident that, 
 if a number of the buttercups or daisies were placed together, 
 ' Lect. i. 324. ' Lect. i. 320. 
 
GENERA L PS YCHOL OGY OF HA MIL TON. 1 1 3 
 
 I would see a yullow or a white patch in the green field, 
 although none of them are visible when taken separately. 
 But each of them evidently contributes to the effect which 
 is ])roduced when they are placed together; for if we place 
 together the smallest number that will render the yellow or 
 white patch visible^ it will disappear on the removal of a 
 single one. This would be more evident if we took objects of 
 larger size, since then^ perhaps, two together would be visible 
 where one was not. When one of these is present, though we 
 are not conscious of any visible effect produced by it, the 
 mind is in a different state from what it would be in if that 
 one was absent ; for it will now be rendered conscious by an 
 object which would not otherwise be capable of exciting it to 
 consciousness. A force of one ton applied to raise a body 
 weighing two tons produces no visible effect, but the bod\' is 
 notwithstanding in a different state from what it was before. 
 It can now be raised by a smaller force than would otherwise 
 be required for that purpose. So a thing which produces no 
 separate impression on our consciousness, may nevertheless 
 render us capable of being affected by causes that would not 
 otherwise affect us. Some minimum of time, moreover, seems 
 to be essential to every act of consciousness; and whatever 
 produces a nervous impression, lasting for a time shorter than 
 this minimum, cannot produce any special state of conscious- 
 ness. But a repetition of such impressions will produce what 
 none of them singly is capable of producing — a great num- 
 ber of undulations being often necessary to produce a sensation 
 of sound, and a still greater number to produce a sensation 
 of colour. In these instances there is no reason to believe that 
 the last of these undulations was more efficacious than the 
 first. They were all similar in character and each produced 
 its separate effect ; but it required the combination of a num- 
 ber of these separate effects to produce any consciousness at all, 
 
 I 
 
1 1 4 S/R WILLI A M HA MIL TON. 
 
 while a further combination would perhaps change that state 
 of consciousness into another. All states of consciousness 
 may therefore be regarded as made up of a number of latent 
 mental modifications. Consciousness and latency are, in fact, 
 separated by no well-marked line. When we pass gradually 
 from latency to consciousness, the consciousness which first 
 appears is so faint as almost to escape our observation. When 
 we pass in like manner from consciousness to latency, the former 
 fades away so gradually that it is usually impossible to fix the 
 precise instant at which it disappears. Of course, I speak of the 
 consciousness of some particular feeling or state ; for, according 
 to Hamilton, we are always conscious. But when one feeling 
 or state of mind is gradually replaced by another (the two 
 being simultaneously present for a time) it is often difficult 
 to fix the moment when the former is finally lost ; and if we 
 turn our fading attention back upon itj we may be at a loss 
 to determine whether what we are then conscious of is a con- 
 tinuance of the old feeling, or a representation of it in the 
 memory. Light is very distinct from darkness : but who will 
 undertake to fix the moment when the one passes into the 
 other during our mornings or our evenings ? And though, of 
 course, light could not be made up of any quantity of abso- 
 lute darkness, all darkness of which we have experience is 
 probably but a diminished quantity of light which, if suffi- 
 ciently multiplied, would reproduce the brightest sunshine. 
 This, in Hamilton's opinion, is the character of all our mental 
 states. 
 
 It has been objected to this argument that a certain quan- 
 tity of the cause may be necessary to produce any of the 
 effect,' and that, therefore, though the mitiimum visibile pro- 
 duces consciousness, an object less than the minimum visible 
 may produce no mental eifect at all. This is perhaps sup- 
 ' Mill's Examination, p. 346. 
 
GENERAL PSYCHOLOGY OF HAMILTON. 115 
 
 posable; but I doubt if there is any instance in nature in 
 which an agent, which in small quantities produces no effect 
 whatever, begins to produce an eflfect when the quantity is 
 increased. An increase in the quantity of the cause indeed 
 sometimes alters the kind of effect, as when by increasing the 
 temperature to a certain point, water begins for the first 
 time to boil; but the heat was producing an effect on the 
 water all through, which was previously evinced by its change 
 of volume and its increased evaporation. The same thing 
 takes place, according to Hamilton, when a distant object acts 
 on the sense of sight. Every portion of it, however minute, 
 produces an effect; but when the quantity is increased to a 
 certain definite amount, there is a change in the kind of effect 
 — it passes from latency into consciousness. It may be said, 
 perhaps, that the latent effect is produced not on the mind 
 but on the nerves. This may be so. The difference between 
 the two theories is very slight, and there seems to be no ex- 
 perimental test for distinguishing between them : nor is there 
 any reason why we may not suppose the effect to be produced 
 on both. 
 
 There are various degrees of latency. The thousandth part 
 of a minimum visibile cannot be supposed to produce as much 
 effect as one half of it ; and the general fact of latency is by no 
 means confined to our sensations. On the contrary, every act 
 of memory consists in bringing some state or feeling from 
 latency into clear consciousness. The effect required for this 
 purpose will be greater or less according to the degree of 
 latency of the thought which we seek to recall. No state 
 of consciousness, in fact, is ever wholly obliterated. It 
 has only become latent. What appeared to have been 
 utterly forgotten is often unexpectedly recalled during the 
 peculiar exaltations of consciousness which take place in 
 certain diseases. Every mental energy once commenced 
 
 1 2 
 
1 1 6 SIR WIL LI AM HA MIL TON. 
 
 continues throuo-bout our whole lives — at first consciously, 
 then in a state of latency, then, perhaps, again recalled to 
 consciousness, and then again latent.' In explaining the 
 theory of the mind latent modifications meet us at every turn. 
 Memory proper — the Couservative Faculty, as Hamilton calls 
 it — is in fact the power of preserving mental states or modifi- 
 cations in the mind, hut out of consciousness. 
 
 This leads us to Hamilton's enumeration of the faculties of 
 cognition or knowledge, which are : 1. Perception, divided 
 into External and Internal. 2. Memory, or the Conservative 
 Faculty. 3. The Reproductive Faculty. 4. The Represen- 
 tative Faculty or Imagination. 5. The Elaborative or Dis- 
 cursive Faculty, the science of whose operations is Logic. 
 And 6. The Regulative Faculty, which, howevei", is a mere 
 name for the entire collection of principles or laws, which as uni- 
 versal and necessary must, according to Hamilton, be a priori, 
 or derived from the mind itself. These laws or principles, 
 however, Hamilton, unlike Kant, does not seek to enumerate 
 in full. In treating of External Perception the question ot 
 Natural Realism naturally crops up, and with it the distinction 
 being the primary and secondary qualities of matter. In 
 Hamilton's Lectures extension and solidity are described as 
 primary qualities, all others being classed as secondary : but 
 in the Dissertations to Reid he divides the qualities of matter 
 into three classes, viz , the primary, which are all reducible to 
 occupation of space ; the secundo-primary, which are likewise 
 all reducible to resistance to our locomotive volition ; and the 
 
 ' Mr. Mill remarks of this doctrine that, if so, I must still be desiring and 
 willing to rise from my bed yesterday morning (Examination of Hamilton, 
 p. 343, note). Hamilton perhaps would ha%'e done well to limit his theory 
 to the persistence of sensible impressions. When reproduced by the 
 imagination these, according to Hamilton, are manifested through the 
 organ which was originally affected by them and may apparently be 
 regarded as weaker forms of the original sensations. 
 
GENERA L PS YCHOLOG V OF HA MIL TON. 1 1 7 
 
 secondary-j embracing the remainder. He likewise distin- 
 guishes between sensation and perception (in the stricter 
 meaning of these terms), the sensation (proper) being the 
 pleasurable or painful feeling which we experience in the 
 exercise of the senses, and the perception (proper) being the 
 knowledge of objects which we gain by this exercise. The 
 law which connects these two is that they are always co-exis- 
 tent, but in the inverse ratio of each other : which is an 
 instance of the more general law that knowledge and feeling 
 always co-exist, but are in the like inverse ratio. The phrase 
 " inverse ratio," however, is not to be taken strictly. " It 
 cannot be said," says Hamilton, "that the minimum of sen- 
 sation infers the maximum of perception, for perception always 
 supposes a certain quantum of sensation. But this is unde- 
 niable that above a certain limit, perception declines in propor- 
 tion as sensation rises." ' This would seem to imply that 
 below this limit we would have a sensation without a percep- 
 tion, in which case Hamilton's statement that they always 
 co-exist would be erroneous. The inconsistency is, perhaps, 
 removed by the corresponding passage in the Dissertations to 
 Reid : " Every perception proper has a sensation proper as its 
 condition ; but every sensation has not a perception proper as 
 its conditionate, unless (what I think ought to be done) we 
 view the general consciousness of the locality of a sensorial 
 affection as a perception proper. In this case the two appre- 
 hensions " [sensation proper and perception proper] " will be 
 always co-existent."^ Adopting this explanation of their in- 
 variable co-existence, however, it can hardly be said that the 
 one always increases in quantity as the other diminishes. Like 
 many of Hamilton's laws, this one would therefore seem to 
 require more accurate expression. It may be remarked that 
 the strength of a sensation is not always to be estimated by 
 ' Lect. ii. 102. » Reid, 880 (a). 
 
1 1 8 SIR WIL LI AM HA MIL TON. 
 
 the amount of pleasure or pain which it produces. There are 
 sensations which are pleasurable in a moderate degree^ but 
 painful when they rise very high ; and in passing from the 
 pleasurable to the painful stage, there must be a point at which 
 the sensation, though by no means feeble in quantity, is almost 
 indifferent. If this is the point at which perception attains 
 its maximum, it might be true that the perception varied 
 inversely with the amount of pleasure and pain which was 
 felt, though not, properly speaking, with the amount of sensa- 
 tion. I do not, however, find any such explanation as this in 
 Hamilton, though the fact of sensations passing from the 
 pleasurable to the painful by an increase of quantity is noticed.' 
 Sir W. Hamilton's doctrine, that all the senses are modifications 
 of touch, has been already noticed. He thinks, however, that 
 a larger number of senses should be distinguished than is 
 usually done, many of the sensations and perceptions usually 
 referred to the sense of touch being different from each other, 
 not merely in degree but in kind. They have nothing in 
 common except that there is no special organ to refer them 
 to.' 
 
 The Conservative, Reproductive and Representative Faculties 
 are closely connected together. The only proof we can give 
 
 ' It may perhaps te said that in such cases the same cause produces 
 two distinct sensations according to the quantity employed — the sensation 
 produced hy a small quantity being a pleasurable, and that by a large 
 quantity a painful, one : and that at the indifference point there is in 
 reality no sensation at all, or rather a sort of fluctuation between very 
 small quantities of the two. Whether this explanation would save the 
 law in question or not, I must leave to the reader. 
 
 ' I need scarcely notice Hamilton's argument to prove that in the 
 perception of sensible objects we begin with the wholes rather than the 
 parts. On principles of Natural Realism the natural inference seems to 
 be that we begin with the oiganic affection. This perhaps always con- 
 tains several sensitive minima, but frequently not enough of them to give 
 us what is called a whole, or entire, sensible object. 
 
GENERA L PS YCHOL OGY OF HA MIL TON. 1 1 9 
 
 that anything has been preserved in the nainory is that it can 
 be reproduced, and when reproduced it is always represented. 
 Some minds, however, are remarkable for the length of time 
 after which portions of their former knowledge can be repro- 
 duced; others for the readiness with which reproduction is 
 effected ; and others again for the vividness of the reproduced 
 ideas. The three faculties may therefore be distinguished. 
 It is in this connexion that Hamilton treats of Association of 
 Ideas. He seems to regard its functions as limited to the 
 phsenomena of reproduction, but over these its control is abso- 
 lute. No idea is ever reproduced otherwise than through the 
 agency of the principle of association. Whenever an idea is 
 reproduced, it is because there has been in the mind, imme- 
 diately before it appears, some other idea which is associated 
 with it. Here, of course, I am taking the word idea in its 
 widest sense. Reproduction may be caused by the presence 
 in the mind of a sensation, a perception, an emotion, or a voli- 
 tion as well as of an image or concept. Every present state 
 of consciousness tends to vivify and call into consciousness all 
 latent modifications which are associated with it, and when- 
 ever a former mental state is reproduced^ it is because it has 
 been thus vivified. It may, however, be vivified not merely 
 by the presence of a state of consciousness associated with it, 
 but by the presence of a latent mental modification associated 
 with it. Suppose two latent modifications, a and b, are simul- 
 taneously present and intimately associated with each other, 
 a being more latent than b. A thought now enters the mind 
 which is associated with a but has no direct association with 
 b. a receives an accession of -strength which renders it less 
 latent than before, but is insufficient to force it into con- 
 sciousness, It will now act with this increased strength on 
 its associate b, and the latter having been less latent than a 
 may appear above the surface. In this way an idea often 
 
I20 S/R WILLIAM HAMILTON. 
 
 seems immediately to excite another whose association with it 
 is only mediate or indirect, the intermediate link, or links, not 
 having risen above the state of latency. The idea which at 
 this instant occupies my consciousness may he regarded as a 
 sort of centre of disturbance. It gives an impetus to all the 
 latent modifications that are in immediate contact with it on 
 any side. These communicate the impulse to the latent 
 modifications in contact with them, and the disturbance 
 spreads outward in wider and feebler circles. But the depres- 
 sion even of a feeble wave may cause an object, which was 
 but a very short distance below the surface, to appear above 
 it; and the objects which appear successively above the sur- 
 face may not be on the same side of the centre of disturbance, 
 but perhaps in quite opposite directions. Again, several 
 states of mind are often simultaneously present to our con- 
 sciousness. These are so many different centres of disturbance, 
 and when the waves propagated from two or more of these 
 centres meet, there may be an exaggerated depression which 
 will cause something to appear above the surface that neither 
 of the disturbances by itself was capable of exciting. Similar 
 effects arise when the exciting mental states are not simul- 
 taneous but successive — when, for instance, a new sensible 
 impression occurs in the midst of a train of thought. It, ia 
 that case, becomes a new centre of disturbance, whose effects 
 are soon blended with the expiring waves of the old one.' It 
 may be further remarked that when a state of consciousness, 
 which we may call x, calls up the idea of y, it frequently 
 
 ' These similes are, of course, in one respect inappropriate. The 
 impulses are communicated to the water, and that which appears above 
 the surface is not the water hut something in it. Ko such distinction 
 exists in the case of the process we are describing. That which appears 
 above the surface has itself received an impulse (mediately or imme- 
 diately), and is of the same nature with everything else that has 
 received it. 
 
GENERAL PSYCHOLOGY OF HAMILTON 121 
 
 continues to exist along with it, and it may even outlast it and 
 call up a new idea z, which is associated not with y but with 
 a;. This occurSj for instance, in what is called intentional 
 memory. We know that the idea we are seeking for is asso- 
 ciated with X. By keeping x steadily before the mind, we know 
 that it will call up a great number of other ideas, all of which 
 are associated with it, and among these we expect that the 
 one we are in search of will appear. Accordingly we keep x 
 in the mind as long as we can, withdrawing as far as possible 
 our attention from everything that it calls up as soon as we are 
 satisfied that it is not the right thing; and the right thing 
 usually appears in the long-run. On other occasions it be- 
 comes necessary, in the acquisition of various dexterities, that 
 a train of associated thoughts should pass through our minds 
 with great rapidity. Here, as a certain minimum of time is 
 essential to consciousness, when the train becomes sufficiently 
 rapid some of the members must drop into latency. This 
 occurs not when the dexterity is imperfect but when it is 
 perfect; and the members of the train are never more influen- 
 tial in practice than after we have ceased to have a separate 
 consciousness of them. 
 
 But what is it that thus associates one idea with another, and 
 enables the former ever afterwards to recall — or rather tend to 
 recall — the latter ? In his Lectures, Hamilton reduces the laws 
 of association to one — the Law of Redintegration — which is 
 thus enounced : "Those thoughts suggest each other which had 
 previously constituted parts of the same entire or total act of 
 cognition.-" ' It has two branches ; for " to the same entire 
 or total act belong as integral or constituent parts, in the first 
 place, those thoughts which arose at the same time or in imme- 
 diate consecution ; and in the second, those thoughts which are 
 bound up into one by their mutual affiinity.'-' ^ These two subor- 
 » Lect. ii. 238. « Ibid. 
 
122 SIR WILLIAM HAMILTON. 
 
 dinate laws are accordingly designated the Law of Simultaneity 
 and the Law of Affinity. In the Dissertations to Reid, how- 
 ever, Hamilton says that the Law of Redintegration is insuffi- 
 cient to explain the whole phjenomenon, without the aid of 
 what he terms the Law of Repetition. The latter law is tlius 
 enounced : " Thoughts co-identical in modification, but differ- 
 ing in time, tend to suggest each other ; " ' while the Law of 
 Redintegration is thus worded: "Thoughts once co-identical 
 in time are, however different as mental modes, again sugges- 
 tive of each other, and that in the mutual order which they 
 originally held."^ There is, however, here no real conflict. 
 What Hamilton calls the Law of Redintegration in his edition 
 of Reid is evidently the same law that he terms the Law of 
 Simultaneity in bis Lectures while the Law of Repetition is 
 identical with, or rather included under, the Law of Affinity. 
 The same two laws thus appear in both places, the only dif- 
 ference being that in the Lectures Hamilton includes both 
 of them under a higher law, which in his edition of Reid 
 is left unnoticed, or rather is replaced by one of a still 
 higher and more abstract character — the Law of Associa- 
 bility. It has been observed already that Hamilton was 
 not quite constant in his employment of philosophical terms.^ 
 It is to be added, however, that Hamilton distinguishes 
 in his edition of Reid between what he calls logical or 
 objective, and psychological or subjective trains of thought. 
 It is over the latter only that the principle of association 
 
 ' Eeid, 912 (b). 2 ggij^ 913 (j,) 
 
 " I am not sure, however, that the Law of Repetition might not have 
 been dispensed with. AVhen for instance, I feel a peculiar kind of pain 
 and recollect that I felt it before, I always remember some of the circum- 
 stances connected with the former pain, thus showing the influence of the 
 Law of Simultaneity. " It is only similarity in the midst of diiference," 
 snys Hamilton, "that associates" [Reid, 915 (a)]; and as soon as the 
 element of difference is introduced we get beyond the Law of Repetition. 
 
GENERAL PS YCHOLOG Y OF HAMIL TON. 1 25 
 
 rules supreme. It is not by means of association of ideas tbat 
 we pass from the premisses of a syllogism to its conclusion ; 
 for this is a necessary sequence, and association is incompetent 
 to account for the phsenomenon of necessity. In like manner 
 it is not by the aid of this principle that we pass from one of^ 
 two relatives to the other, for in the thought of either relative 
 that of the other is necessarily implied. There is indeed an am- 
 biguity in the language often employed on this subject which it 
 is necessary to clear up. Premiss and Conclusion, for instance, is 
 in one sense a Law of Association (being a special branch of the 
 Law of Affinity). Thus, one (or both) of the premisses from 
 which I formerly deduced a certain conclusion, occurring- 
 to my mind simply as a judgment or proposition, may 
 recall that conclusion under the influence of the Principle 
 of Association ; but if both premisses are present to my 
 consciousness, and I think of them as premisses, it is not 
 the Principle of Association that calls up the conclusion. 
 That is the act of the Elaborative Faculty, and an act 
 which would equally take place if I had never drawn that 
 conclusion from the same premisses before — an act similar 
 to that which took place when I first inferred it. And 
 this conclusion is not one of many mental states which the 
 thought of the two premisses might recall as more or less 
 connected with them. It follows invariably and necessarily, 
 provided, of course, that I think of the premisses as pre- 
 misses. A train of reasoning can indeed be carried on to a great 
 length with little or no aid from the principle of Associa- 
 tion, assuming that the various premisses employed in the 
 argument are brought before the mind in some other way ; 
 as, for instance, in reading an argumentative book. The 
 suggestion of the things signified by the signs or words em- 
 •nloyed, seems to be, in that case, all that is properly ascribed, 
 to association. 
 
124 SIR WILLIAM HAMILTON. 
 
 Besides forming the main subject of Logic, the considera- 
 tion of the Elaborative Faculty introduces us to the nature 
 of the process of abstraction and the disputes between the 
 Nominalists and Conceptualists on the subject of General 
 Notions or Ideas. According to Hamilton abstraction con- 
 sists in converging our attention on some parts of an object 
 (or of a number of objects present to tlie mind simultaneously) 
 whilst not attending to the remaining parts. All objects are 
 at first presented to us vaguely and in confusion. The maxim, 
 Divide et impera, is applicable to them all, and without 
 this convergence of attention on portions of them we can get 
 no clear notions at all. Abstraction is as necessary for the 
 formation of the notion of the individual as of the class; for 
 in the early confused state of knowledge, children are apt to 
 confound individuals not only in name but in reality. It is 
 by concentrating attention on the points of difierence that 
 children come to distinguish one person from another, as by 
 concentrating attention on the points of resemblance they 
 come to regard both as men.' But the parts on which atten- 
 tion can thus be converged are of two kinds. They may be 
 integrant parts of the thing, like the arms and legs of a man, 
 or they may be modes or qualities, such as his figure, size, 
 and colour. Hence there ai'e two kinds of abstraction, which 
 Hamilton designates Partial or Concrete Abstraction, and 
 Modal Abstraction. The latter kind of abstraction, espe- 
 cially, seems to be intimately connected with generalization. 
 The general idea, or concept, is not properly an idea, but that 
 part of a perception, or idea, on which our attention is con- 
 
 ' Hamilton often speaks of abstraction as a negative, not a positive state 
 of mind, consisting merely in non-attention to certain parts of an object. 
 But non-attention to tbese parts necessarily implies that our attention is 
 conyerged on the other parts. 
 
 " Pluribus intentug, minor est ad singula sensus " 
 and vice versd. 
 
GENERAL PS YCHOL OG Y OF HAMIL TON. 1 25 
 
 eentrated. It is a mode of considering ideas — a point of 
 view from which they may be regarded. Hence it cannot be 
 pictured in the mind by itself, for it is impossible to realize a 
 way of regarding' things, except in connexion with some of 
 the things so regarded. The term Man indicates a way of 
 regarding John Smith, Tom Brown, and every other indivi- 
 dual to whom that term is applicable, and it cannot be depicted 
 in imagination apart from some of these individuals. It 
 results, in fact, from a comparison between a number of sensible 
 impressions by which we separate the points in which they 
 resemble each other from those in which they differ ; but this 
 act of comparison cannot take place unless we have something 
 (or rather, some things), to compare. We can associate 
 this mode of regarding things with a name, so that when- 
 ever the name is pronounced we are reminded of the point 
 of view from which they are to be considered ; but it is this 
 mode of regarding things that gives meaning and significance 
 to the name and not vice versd. No name can enable us to 
 regard things from a point of view which would otherwise be 
 impossible. General names, however, have this advantage, 
 that they are associated with the things to be compared, as well 
 as with our mode of comparing them, and they thus recall 
 both at once when it is requisite to do so. They recall, in 
 fact, both their denotations and their connotations. Thus the 
 name Man usually recalls at once one or more individual 
 men, and at the same time reminds us that our attention is to 
 be converged on the points in which these individuals agree, 
 to the exclusion of those in which they differ.' But the con- 
 cept can exist without the general name, whereas without the 
 concept, the general name would sink into a proper name, 
 
 ' Or rather on some of the points in which they agree ; for the men we 
 call up in imagination usually agree in more points than those which are 
 connoted by the name Man. 
 
1 26 SIR WILLI A M HA MIL TON. 
 
 ambiguously applied to more than one individual. The word 
 Man, in fact^ would, in that case, mean John when applied to 
 John, and Peter when applied to Peter ; and being thus 
 subject to greater ambiguities and inconveniences than ordi- 
 nary projier names, it would very soon sink into disuse. 
 When the true character of the concept is thus explained, 
 Hamilton thinks the dispute between Nominalism and Con- 
 ceptualism is at an end. When the Conceptualists affirmed 
 the existence of General Ideas, they were supposed by their 
 opponents to mean General Intuitions, or General Images 
 (Imaginations), which do not exist. When the Nomi- 
 nalists denied the existence of General Ideas, their opponents 
 understood them as denying that there were any General 
 Concepts, in which case all generalization would be impos- 
 sible. Both were really agreed that there are no General 
 Intuitions or Images, but that there are General Concepts. 
 That some of the disputes between the Nominalists and the 
 Conceptualists turned on the ambiguity thus signalised by 
 Sir William Hamilton, cannot, I think, be doubted; but it 
 may be questioned whether all of them did so. There is, in fact, 
 no controversy with regard to which it is more difficult to 
 ascertain what was the precise point in dispute. Some Nomi- 
 nalists (for instance, Berkeley) denied the possibility of the 
 process which Hamilton terms Modal Abstraction ; but the 
 existence of that process has been admitted by so manj^ pvo- 
 fessed Nominalists, that it would almost seem a paradox to 
 say that its possibility was the principal subject in dispute. 
 If this distinction were adopted, Hamilton should be classed 
 as a Conceptualist. His own statement of the question, in 
 his Lectures is this : Can we form an adequate idea of 
 that which is denoted by an abstract, or abstract and general, 
 term ? ' But as he apparently answers this question in the 
 ' Lect. ii. 296. But is there not at least as good reason for putting the 
 
GENERAL PSYCHOLOGY OF HAMILTON. 127 
 
 negativej we can hardly suppose that he thought it was really 
 the point in dispute, since he elsewhere represents the dit- 
 ferences between the contestants as purely verbal. How- 
 ever, the question, as thus stated, is by no means free from 
 ambiguity. For what is meant by the word " idea," and what 
 is meant by the word "adequate"? If the idea of a class 
 is required to be adequate not only to the class, but to every 
 sub-class and even to every individual comprised in it, such 
 an idea is doubtless impossible; nor, probably, had Locke any 
 intention of asserting the contrary, in the passage of his Essay 
 so often cited on the subject. But if we regard the idea of a 
 class as adequate whenever it is sufficient to distinguish that 
 class from every other class, whether higher, lower, or co-ordi- 
 nate, then there is no reason why we should not have an ade- 
 quate idea of that which is denoted by a general term. If my 
 idea of a triangle was adequate to the sub-class right-angled 
 triangle, this would not be a perfection but a blemish. Con- 
 sidered as a representation of the class which it was intended 
 to represent, it would be, not adequate but, redundant. Pro- 
 bably, no one ever has an adequate — meaning by that term a 
 complete, or perfect — idea of the extension of a general term; 
 but there is no reason why he should not have an adequate 
 idea of its comprehension. Hamilton's discussion of the 
 entire subject is, however, confessedly incomplete, since he 
 does not even attempt to carry out in full the design which 
 he states when introducing the subject.' He seems to have 
 finally decided on devoting most of the time at his disposal to 
 a refutation . of the theory of Brown, and we are thus pre- 
 
 question in the form : Can we form an adequate idea of that which is 
 foranoted bj a general tei-m? Pussibly Hamilton intended to include this, 
 for he does not seem to have employed the word rfenote in the limited 
 signification — as contra-distinguished from the word connote — in which it 
 is used by Mr. Mill. 
 ' Lect. ii. 296. 
 
12S S/R WILLIAM HAMILTON. 
 
 sented with the negative rather than the positive side of his 
 doctrine.' 
 
 Connected with this subject is Hamilton^'s Theory of 
 Judgments/ which has also been severely criticised. It 
 is certainly wanting in that clearness and precision which 
 we usually meet with in his writings, but his critics 
 will find it no easy task to convict our author of any 
 positive error. The theory is developed at greater length in 
 the Lectures on Logic than in those on Metaphysics, and in 
 both cases the exposition includes numerous quotations from 
 other authors, in making which Hamilton does not seem to 
 have paused to point out that they were not always using 
 psychological terms in his own restricted meaning. Nay, 
 in some instances, when commenting on these passages, he 
 seems to have slided into employing these terms in the vaguer 
 sense of the authors whom he is citing. Thus, in the Lectures 
 on Metaphysics, he quotes with approbation from Crousaz, 
 " Every time we judge, we compare a total conception with a 
 partial, and we recognize that the latter really forms a part 
 of the former;" ^ in commenting on which Hamilton remarks 
 " Judgment is conversant with two notions, one of which is 
 contained in the other."'' (The italics are mine.) Now 
 undoubtedly if the words " conception " (or concept) and 
 " notion " are here taken in their strict sense, these descriptions 
 
 ' From the pleasure which Hamilton expresses in one of his letters to 
 Cousin at fiading that Abelard was a Conceptualist, it would seem that at 
 that time he preferred the Conceptualistio doctrine. See Professor 
 Veitch's Memoir of Hamilton, p. 199. 
 
 ^ Judgment according to Hamilton is involved in every act of conscious- 
 ness, since there is always a contrast and discrimination of two things 
 at least. The remarks in the text are confined to those judgments 
 which may be translated into propositions with a subject and predicate 
 or to what Dean Mansel terms logical (as opposed to psychological) judg- 
 ments. 
 
 3 Lect. ii. 336. " Lect. ii. 337. 
 
GENERAL PS YCHOLOG Y OF HAMIL TON. 1 2; 
 
 are objectionable. The conception or notion runiiiuint, foi 
 instance, is not contained in the conception or notion cloven- 
 footed, or vice versa : and when I judge that all ruminating 
 animals are cloven-footed, the subject is not a total conception 
 which I compare with a partial conception (the predicate), nor 
 do I find that the conception cloven-footed is really a part of 
 the conception ruminant or ruminating animal.' Thus under- 
 stood, the description of Crousaz would in fact only be correct 
 if all judgments were what Kant termed Analytical or Expli- 
 cative judgments. But Hamilton did not, nor probably did 
 Crousaz, intend to convey this meaning. For Hamilton 
 expressly tells us that this relation of whole and part may 
 exist between the extensions, as well as between the compre- 
 hensions, of the two conceptions or notions, and he even 
 thinks he has made a valuable addition to the science of 
 Logic, by distinguishing between reasoning in comprehension 
 and reasoning in extension. Now if the words conception 
 and notion are understood strictly, it is absurd to speak of two 
 notions or conceptions standing to each other in the relation of 
 whole and part, because their extensions do so. The notion 
 Black is not a part of the notion Man, nor is the notion Man 
 a part of the notion Black, because these two notions happen 
 to have, to a certain extent, a common extension. Considered 
 merely as notions, there is no other relation between the notion 
 
 ' Unless we use the terms "conception" and "notion" to include all 
 (known) properties of the class and not merely those which are connoted 
 by class-name — which certainly was not Hamilton's ordinary use of 
 terms in question. In this extended meaning, cloven-feet beino- a (known) 
 property of the class ruminant, forms a part of the notion or conception 
 ruminant, and rumination being a (known) property of the class cloven- 
 footed, forms a part of the notion or conception cloven-footed. Rumman 
 and cloven-footed are in fact, on this theory, two names for the same notion 
 or conception. This use of language, however, seems to me very con 
 fusing: and productive of no benefit. 
 
I30 S/R WILLIAM HAMILTON. 
 
 Black and the notion Man, than between tlie notion Green 
 and the notion Man, nor could the mere comparison of notions 
 or conceptions lead us to form any judgment as to the con- 
 nexion of the former pair which was not equally applicable to 
 the latter. Hamilton, therefore, must be understood in these 
 and similar passages as using the words Conception, Notion, 
 Thought, &c., in a signification wide enough to include the 
 extension as well as the comprehension of the terms which 
 form the predicate and subject of a proposition : and of course 
 when he speahs of comparing concepts or notions, we must 
 equally understand him as referring to the comparison of their 
 extensions, no less than of their comprehensions. The former 
 comparison may have originally been the work of experience, 
 but when the requisite experience has once been attained, it 
 may not be necessary to go beyond the comprehension and 
 extension of the terms (as recalled to the mind by the 
 enouncement of the proposition), to enable us to judge that 
 the proposition is true. To this, perhaps, I ought to add that 
 judgment does not of itself imply belief. A judgment must 
 be present to the mind in order to be doubted or disbelieved. 
 Logic, as Mr Mill has well remarked, does not concern itself 
 with the act of belief but with that which is believed,' or 
 rather perhaps he should have s;iid, with that which is proposed 
 or tendered for belief. That which is proposed for belief is a 
 judgment or proposition : and even if it be true that mlien 
 believed, it is believed on the evidence of experience, the 
 judgment itself, as distinguished from the belief in it, may he 
 the result of a mere comparison of concepts (in the strict 
 sense) by the Elaborative Faculty. I doubt, however, whether 
 Hamilton would have given this explanation of some of the 
 expressions I have cited from him. The real source of the 
 
 ' Lo^ic i. 96 (8th edition). Tlie observation is hardly consistent with 
 some of his criticisms on the Hamiltonian theory of judgment. 
 
GENERAL PSYCHOLOGY OF HAMILTON. 131 
 
 difficulty in following his exposition is, I believe, that he has 
 entirely omitted to signalize the distinction between Ana- 
 lytical and Synthetical Judgments in connexion with it 
 (he has noticed it elsewhere), and this omission taken in 
 connexion with the loose employment of the terms con- 
 ception or concept and notion has left his expressions open 
 to much misconstruction.' 
 
 The sole operation of the Elaborative Faculty is comparison. 
 When this comparison is made between two concepts, the 
 result is a Judgment. Of concepts, considered in pairs, the 
 great division is into Congruent or Agreeing (that is concepts 
 which can be united in thought) and Conflictive, or 
 those which cannot. Hamilton gives this as a division of 
 concepts "considered under their comprehension," so that, 
 apparently, he could not refer to the extension of the concepts 
 to determine whether they were congruent or conflictive : 
 and as the two sub-classes include the whole class to be 
 divided, all concepts which are not conflictive must be treated 
 as congruent. The conflict between the different elements of 
 a concept, however, may be only mediate, and may therefore 
 require considerable pains to detect. On this division depends 
 Hamilton's fuller expression of the Theory of Judgments. To 
 iudge is, according to him, "to recognize the relation of con- 
 gruence or confliction in which two concepts, two individual 
 
 ' Hamilton evidently was not quite satisfied with his own language on 
 the suhject. Thus Lect. iii. 140, he makes applicability to an indefinite 
 plurality of objects (extension) a characteristic of every concept, and speaks 
 of extensive quantity as essential to it. But in a note he suggests as a 
 " better (?) " division, " 1. By relation to themselves, they " [concepts] 
 " have the quantity of comprehension ; 2. By relation to their ohjects, they 
 have the quantity of extension," &c.; thus apparently describing the former 
 quantity alone as intrinsic and essential, and the latter as accidental and 
 dependent on the constitution of the objective world. See also the passage, 
 Lec-t. iii. 218, which is quoted at pp. 147-8 of this book. 
 
 K 2 
 
132 SIR WILLIAM' HAMILTON. 
 
 things, or a concept and an individual compared together, 
 stand to each other;"' and of course in the more importaut 
 cases, the relation is recognized as existing between two con- 
 cepts. When the relation thus recognized between the subject 
 and the predicate is one of congruence, we unite the two into 
 a single thought, and this thought is a judgment. We 
 cannot unite the two concepts into a single concept or notion 
 without making them the subject and predicate of a judgment, 
 nor can we make them the subject and predicate of a judg- 
 ment without uniting them into a single notion. Congruent 
 concepts being those which are capable of being so united, 
 become the subject and predicate of an affirmative judgment 
 when we bring them together, while conflictive concepts 
 equally fall into the position of subject and predicate in a 
 negative judgment. A further explication of the process, 
 however, would here be desirable ; for, to deal with affirmative 
 judgments only, it is evident that the concepts described by 
 Hamilton as congruent may be of two different kinds. They 
 may be such as we must necessarily' unite in thought, or such 
 as we may or may not unite according to circumstances.-* 
 Man and Animal are concepts of the former kind. The com- 
 prehension of the concept Animal being part of the com- 
 prehension of the concept Man, we see at once that the latter 
 concept is inseparable from the former. They are so con- 
 gruent that we cannot help judging and believing that all 
 men are animals. But the concept Man and the concept 
 Ten-feet-high are congruent in a ditfereut sense. They are 
 capahle of being united in thought, but we are not under any 
 
 1 Lect. iii. 225-6. 
 
 ^ Tliis distinction is indeed essential to a pbilosophy which, like Hamil- 
 ton's, distinguishes between a priori and a posteriori — necessary and 
 empii-ieal— judgments. And as we shall see, it is recognized by Hamilton 
 in his divisions of concepts, though he does not carry it on to bis theory 
 of judgments. 
 
GENERA L PS YCHOL OGY OF HA MIL TON. 1 3 3 
 
 necessity of unitiog them : or if it be said that whenever con- 
 cepts capable of being united in thought are brought together 
 in the mind, we in (act unite tliem and form a judgment; we 
 are at all events under no necessity of believing the judgment 
 so formed, and may indeed doubt or disbelieve it. If we 
 judged universally that all men are ten feet high or that all 
 objects ten feet high are men, these judgments would be 
 disbelieved as inconsistent with the most ordinary experience. 
 But if we judged that some men are ten feet higli, there are 
 recorded instances of giants approaching sufficiently near to 
 that standard to render the proposition credible, and the proper 
 position of the mind in regard to it would probably be one 
 of doubt. Hamilton however has omitted to notice this 
 distinction in his theory of judgments, and often speaks as if 
 the recognition of the congruence of two concepts (that is, of 
 their capability of being united in thought) was sufficient not 
 only for the formation of the judgment, but also for our belief 
 in it. He had three courses open to him, none of which he 
 seems to have definitely adopted. First, he might have defined 
 congruent concepts not as those which may, but as those which 
 mud, be united in thought : in which case, however, he could 
 not divide all concepts into the two classes congruent and 
 conflictive without denying the possibility of synthetical or 
 ampliative judgments a ^joiiJeHon. Secondly, he might have 
 expressly told us that he was merely considering judgments 
 or propositions in themselves, as distinguished from the belief 
 in them, and that the recognition of the congruence of two 
 concepts was sufficient for the formation of a judgment, 
 though not for our acceptance of it as true. Or lastly, he 
 might have stated that in order to form a judgment, the two 
 concepts compared must be congruent in their extension.s, and 
 that this congruence of extensions required that they should 
 be capable of being united not merely in thought but also in 
 
134 SIR WILLIAM HAMILTON. 
 
 presentation. The last solution I suspect approaches most 
 nearly to Hamilton's real opinions. But, in fact, the division 
 of concepts into congruent and conflietive is objectionable. 
 There are three classes of concepts not two, viz. those which 
 must be united in thought, those which cannot, and those 
 which may or may not, according- to circumstances.' With 
 regard to this latter class a partial uniting and partial dis- 
 uniting often takes place simultaneously. We judge simul- 
 taneously that Some Men are Black and Some Men are not 
 Black; and if we are to base the distinction of judgments 
 into affirmative and negative upon the division of concepts into 
 congruent and conflietive, we must apparently describe the 
 concepts Man and Black as both congruent and conflietive. 
 
 Elsewhere, as we have seen, he describes the relation be- 
 tween the concepts which form the subject and predicate of a 
 judgment as one of whole and part, and hence he has some- 
 times been understood as asserting that two concepts were 
 only congruent when one formed a part of the other. But in 
 the face of his explicit statements that this relation of whole and 
 part may exist between the extensions of the two concepts, this 
 interpretation seems inadmissible. That the relation of whole 
 and part exists between the extensions of the subject and pre- 
 dicate of an afiirmative proposition is undeniable, at least, 
 if we use the word " part " in a sense wide enough to take in 
 the case of two co-extensive or coincident wholes. Every B 
 is C, asserts that the extension of B is a part of the extension 
 ofC. Thus explained the theory appears unobjectionable. The 
 difficulty is to reconcile it with the previous theory of con- 
 gruence. If the comprehensions of two concepts are quite 
 
 ' Accordingly, before dividing concepts into congruent and conflie- 
 tive, Hamilton divides them into Identical (or rather Cognate) and 
 Different ; but he seems to have forgotten the former division when he 
 came to treat oCjudgments, though it is on it that Analytical Judgments 
 should apparently have been based. See p. 144. 
 
GENERAL PS YCHOL OG Y OF HAMIL TON. 135 
 
 distinct from, but not inconsistent with, each other, are these 
 concepts to be classed as congruent or as conflictive, accord- 
 ing as we find by experience that the extension of one does or 
 does not form a part of the extension of the other? Possibly 
 Hamilton might have replied that in the extension of a concept 
 he included its imaginary, as well as its real, extension — that 
 under the concept Serpent, for instance, he included dragons 
 as well as really existing serpents — and that any two concepts 
 that could be united in thought must possess an imaginary, if 
 not a real, extension in common. He sometimes speaks, 
 however, as if the relation of whole and part in extension 
 always corresponded (though, of course, inversely) with the 
 same relation in comprehension. He speaks as if the truth 
 of the proposition Every B is C implied that the comprehension 
 of the concept B contains or includes the comprehension of the 
 concept C. Thus Man is Two-legged means, according to 
 Hamilton, either that (the concept) Man includes the attri- 
 bute Two-legged, or that (the class) Man is included in the 
 class Two-legged (or as in this case he prefers to write it, the 
 class Biped),' and he employs this instance to explain the 
 
 ' Hamilton's distinction between judgments in comprehension, and 
 judgments in extension seems of little importance. Every judgment can, 
 as he tells us, be read in both ways. But when the predicate is an adjective 
 our attention is more immediately directed to its comprehension as an 
 attribute belonging to, or as Hamilton would say, contained or included 
 in, the subject ; while when the predicate is a substantive, our attention 
 is chiefly directed to its extension, as a class containing or including tlie 
 subject under it. In the English language the subject is always a 
 substantive, and thus its extension, rather than its comprehension, would 
 seem to be always the primary object of attention ; but Hamilton seems 
 to think that in this respect it follows the predicate, so that when the 
 predicate is an adjective, the judgment primarily e.tpresses the relition 
 between the comprehensions of the two concepts, while when the predicate 
 is a substantive, the judgruent primarily expresses the relation between 
 their extensions. And he sometimes describes this relation in both cases 
 
136 SIR WILLIAM HAMILTON. 
 
 natAire not of Analytical or Explicative Judgments in particu- 
 lar, Lut of judgments in general. "We can hardly suppose that 
 in this and similar passages, he employs the term concept and 
 its equivalents in the vague sente iu which they refer to the 
 extension as well as the comprehension of the general name, 
 for he is speaking of the relations which exist between the 
 comprehensions of the subject and the predicate.' There is 
 indeed one mode of interpretation in which we may regard 
 the comprehensions of the subjects and predicates of all 
 affirmative propositions as standing to each other in the 
 relation of whole and part. We may understand All Men are 
 Mortal as a short expression for All Men are Mortal-men, and 
 All B is C as a short expression for All B is C-B. In this 
 case the comprehension of the predicate is always a whole of 
 which the comprehension of the subject is a part, and, under- 
 standing jtjar/! in the wide sense already mentioned, the corre- 
 sponding relations as regards extension would also hold good. 
 This, however, cannot be Hamilton^'s meaning, for he states 
 that in comprehension the subject is the whole and the pre- 
 dicate the part. I cannot, therefore, profess to have given a 
 complete explanation, or complete defence, of the theory. 
 There can be no doubt, however, that if Hamilton had written 
 a formal treatise on Logic after he had adopted the theory 
 of the Quantification of the Predicate, this part of his exposi- 
 tion would have been largely altered. As regards extension, at 
 least this latter theory abolishes the relation of whole and part, 
 
 as one of whole and part, tliough, of course, the wholes and parts are 
 inverted when we pass from comprehension to extension or vice versa. 
 
 ' Nay, the quantity of extension is sometimes even made to depend on 
 that of comprehension. See Lect. iii., 218. But perhaps Hamilton is 
 there tipealiingj of the comprehension and extension of a single concept, 
 ratlier than of the mutual relations of two concepts in comprehensioa 
 and extensiim. 
 
GENERAL PSYCHOLOGY OF HAMILTON. 137 
 
 and replaces it by one of equation, or rather identification. 
 The subject will be dealt with in the next chapter. 
 
 In Hamilton's discussion of the Feelings or Emotions the 
 only point specially worthy of notice is his Theory of Pleasure 
 and Pain. Pleasure, according to him, always accompanies 
 the exercise of a perfect energy, while pain similarly attends 
 on an imperfect one. Instead of " energy," we might perhaps 
 substitute " state of consciousness ;" for Hamilton tells us 
 that he uses the former term to include mixed states of action 
 and passion, while he is of opinion that no state of conscious- 
 ness is purely passive. The imperfection of an energy is two- 
 fold — it may be repressed or over-strained — it may be in 
 excess or in defect — and this again may be an excess or defect 
 either in degrpe or in duration. Nay, since the mind is capa- 
 ble of exerting more than one energy, and of attending to more 
 than one object, at the same time, a third kind of imperfection 
 is possible. The mind may either attempt to embrace too 
 many things at once, or the objects of consciousness may be 
 too few to occupy it fully. In either of these cases the result- 
 ing feeling is painful. But in all cases when the energy is 
 spontaneous and unimpeded it is pleasurable. When forced 
 or impeded it is painful. 
 
 This theory, like many others, has been made the subject of 
 adverse criticism. What, it is asked, is the test of the per- 
 fection of an energy ? And if no test can be assigned except 
 the resulting pleasure, then it is said that the law in question 
 is a merely verbal one. Pleasure is the concomitant (or the 
 effect) of a perfect energy, simply because we only call the 
 energy perfect when pleasure results from it; and pain is 
 likewise the concomitant of an imperfect energy, merely be- 
 cause when the energy results in pain we choose to call it im- 
 perfect. But there seem to be some consequences of the 
 theory by which its truth may be tested, and an examination 
 
138 SIR WILLIAM HAMILTON. 
 
 of these results will be found, on the whole, favourable to it. 
 First it follows from the theorj', that every pleasurable feeling 
 or state of consciousuess will become painful if its intensity is 
 sufficiently increased, or its duration sufficiently prolonged. 
 This appears to be the case ; and it will also be admitted that 
 when we are bent on any particular kind of enjoyment the 
 constant intrusion of fresh ideas is a source of annoyance, even 
 though we might have derived pleasure from them under 
 different circumstances. An excess in the extensive quantity 
 of our mental energies is thus disagreeable. Secondly, it 
 follows that every pleasurable feeling may be so weakened, or 
 so shortened in duration, as to be productive of pain instead of 
 pleasure. Where, however, it is weakened, it will only produce 
 this painful feeling provided it continues to be the principal 
 object on which our attention is concentrated; for if it is 
 allowed to slip into the background while a new and interest- 
 ing object occupies the foreground, the resulting feeling will, 
 on the whole, lie one of pleasure. In general the extensive 
 quantity of our mental energies must always be taken into 
 account, as well as their intensive and protensive quantities. 
 With this qualification our second consequence seems to be 
 verified by experience. The abrupt termination of a plea- 
 surable feeling, while still tolerably intense, is always painful, 
 though the feeling which causes the interruption may not be 
 so in its own character ; and there is hardl}-, for instance, an 
 agreeable article of food which may not be rendered unpleasant 
 by simply diluting it with a sufficient quantity of a tasteless 
 fluid like water.' A third consequence of the theory is that 
 man}' painful feelings will become pleasurable when their 
 
 ' Brevity, it has been remarked, is the soul of wit ; and how often is 
 the pleasure which we derive from some terse and powerful sentence, 
 changed to disgust on reading a lengthy paraphrase. These facts admit 
 of the same explanation. 
 
GENERAL PSYCHOLOGY OF HAMILTON. 139 
 
 intensity is sufficiently lessened^ or their duration sufficiently 
 diminished ; that many others will become pleasurable when 
 their intensity or duration is sufficiently increased ; and that 
 all painful feelings will fall either into the former or the 
 latter of these classes. Here again a good deal may be said 
 for the theory, though much remains to be done before all 
 pains can be brought under either of our classes. It is to be 
 recollected, however, that some of our feelings have got no 
 names unless they exist in a degree which is painful — a 
 fact which sometimes gives the Hamiltonian theory an ap- 
 pearance of paradox. It would sound very startling to allege, for 
 instance, that a toothache might be so diminished in intensity 
 as to produce pleasure instead of pain ; yet I am not sure that 
 we do not feel a pleasurable sensation in the tooth just as the 
 toothache is ceasing. A pleasure of this kind is sometimes re- 
 ferred to contrast, or relied on to prove that pleasure is the mere 
 negation or the absence of pain ; but it may also be accounted 
 for, by supposing that the sensation which had been painful 
 passes through a pleasurable stage before finally vanishing.' It 
 may be said, indeed, that on Hamilton's theory it ought to 
 pass through a second painful stage before its disappearance. 
 But this is only true, as already remarked, when it continues 
 to be the principal object of attention. The feebleness of an 
 energy produces no painful results, if other energies of a more 
 vigorous character are simultaneously present. It may be 
 observed that, if true, the Hamiltonian theory would afford a 
 scientific basis for the precepts frequently laid down by practical 
 
 ' After severe pain or any great over-straining of our powers, their 
 spontaneous degree of energy — that degree which alone produces pleasure 
 — will be unusually low. The pleasurable degree of a sensation or other 
 feeling will in such cases be not far removed from the vanishing point. 
 If it falls lower than this — when on Hamilton's theory it should again 
 become disagreeable — it very soon sinks into latency. 
 
I40 S/Ji WILLIAM HAMILTON. 
 
 Moralists. It would prove that moderation is the true road to 
 earthly happiness, and that if pleasure is pursued too ardently 
 and too exclusively it will not be attained. Work, but not 
 over-work, would seem to be the most pleasurable condition for 
 mankind. These observations will, I trust, satisfy the reader 
 that the theory in question, whether true or not, is not merely 
 verbal or unimportant. 
 
CHAPTER VII. 
 
 LOGIC. 
 
 In dealing with Sir W. Hamilton's theory of judgments I 
 have, to a certain extent, anticipated his views on the subject 
 of Logic. He adopted a strictly formal view of the nature of 
 that science which he defines as " the science of the laws 
 of thought, as thought," or the science of " the formal laws 
 of thought" — those laws of thought which are alike appli- 
 cable to all the products of the thinking faculty, which are not 
 limited to any special subject-matter, and which are universal 
 and necessary. Thought, which forms the subject-matter of 
 the science, is to be distinguished both from the presentations 
 of the senses and the representations of the imagination. It 
 is a general name for the products of the Elaborative Faculty, 
 as described in the Lectures on Metaphysics — a faculty whose 
 sole function is comparison, and whose three great products 
 are Conceptions (or rather Concepts), Judgments and Reason- 
 ings. As the mental operations can seldom be wholly sepa- 
 rated from each other, an act of thought in which no other 
 faculty has intervened may, perhaps, be impossible, and the 
 laws and limitations of other mental faculties operate con- 
 jointly with the laws of thought in almost all the products of 
 that faculty : hut though some account of these may be taken 
 in what is termed Modified Logic, in Pure Logic we must 
 abstract from them altogether. A concept is a general notion, 
 the nature of which had been already explained in the Lectures 
 
142 SIR WILLIAM HAMILTON. 
 
 on Metaphysics; a judgment, as we have also seen, expresses 
 a relation of congruence or confliction between two concepts ; 
 and a reasoning again arises from a combination of two 
 judgments. Such are the products of thought with which 
 Logic deals, and the formal laws which govern the several 
 operations of thought are the principles of Identity, Contra- 
 diction (or Non-contradiction), and Excluded Middle, which 
 Hamilton regards as three different pliases of the same funda- 
 mental law. To these, in his Lectures on Logic, he adds the 
 principle of Sufficient Reason, or of Reason and Consequent — 
 to which he attributes the form of the Hypothetical Syllogism.' 
 In his Discussions, however, he states that the only principle 
 of Sufficient Reason which should be employed in Logic is 
 derived from the other three, to which we may therefore con- 
 fine our attention.^ They apply alike to concepts, judgments, 
 and reasonings, but their application to the two former is not 
 so obvious, and it cannot be said that Hamilton has fully 
 explained it. The principles of Contradiction and Excluded 
 Middle can, it is true, be easily applied to concepts, but their 
 use is merely negative. They declare the invalidity of an 
 alleged concept which comprises both or neither of two con- 
 tradictory attributes, but as regards the formation of concepts 
 they do not offer us any assistance. The principle of Identity, 
 according to Hamilton, "' expresses the relation of total same- 
 ness in which a concept stands to all, and the relation of 
 partial sameness in which it stands to each, of its constituent 
 characters. In other words it declares the impossibility of 
 thinking the concept and its characters as reciprocally un^ 
 like.'" This, again, does not explain the formation oi con- 
 cepts. In fact it seems only applicaljle io judgments, in which 
 we affirm the existence of a relation of total or partial same- 
 
 ' Lect. ill. 337. ' Discussions, 160, note, 603. 
 
 8 Lect. iii. 80. 
 
LOGIC. 143 
 
 ness between the concept and its characters. And accord- 
 ingly Hamilton, after giving the symbolical expression of the 
 law (A = A), goes on, "The law has likewise been expressed 
 by the following formula — In the predicate the whole is con- 
 tained explicitly, which in the subject is contained implicitly.''' 
 This latter expression is clearly referable not to concepts, but 
 to judgments, and is moreover limited to analytical or expli- 
 cative judgments : and therefore we need not be surprised 
 to find our author adding, " The logical importance of the 
 law of Identity lies in this — that it is the principle of all 
 logical affirmation and definition ;" affirmations and defini- 
 tions being, of course, judgments, not concepts. In like 
 manner he says of the law of Contradiction (No A is non-A), 
 " The logical import of this law lies in its being the principle 
 of all logical negation and distinction'';' and the law 
 of Excluded Middle (whatever is not A is non-A), he 
 remarks is "the principle of disjunctive judgments."' All 
 
 ' Lect. iii. 82. The symbolical expression of this law is printed 
 A = non-A = 0, and Mr. Mill comments on this misapplication of 
 mathematical formulae [Examination, 485). I should have thouo-ht 
 that the misprint was obvious to any commentator. The true expression 
 of course is A + non-A = 0, which is identical in meaning with the 
 alternative form A — A ^ .0 
 
 2 Lect. iii. 84. Hamilton gives no symbolical xpression for the law of 
 Excluded Middle. That which naturally occurs to us is, A -|- non-A = 00 
 (or A — A = 00) which is mathematically untrue, and also apparently 
 conflicts with the symbolical expression of the Law of Contradiction, viz. 
 A -I- non-A = 0, or A - A = 0. This latter conflict, however, is only 
 apparent, and arises from the fact that the latter formulje relate to compre- 
 hension, and the former to extension— quantities whose variations are 
 usually of an inverse character. But the fact that both these quantities 
 must be regarded in Logic, renders the application of Algebraical formula 
 to that science difficult, if not impossible. If A stands for an attribute or 
 collection of attributes, the equations into which it enters will be very 
 different from those which affect it when it stands for a class or collection 
 of objects. 
 
144 ^^/^ WILLIAM HAMILTON. 
 
 these passages occur when our author is explaining the rela- 
 tion of these principles to concepts, and he has not, I believe, 
 anywhere endeavoured to show that the formation of con- 
 cepts is affected by the laws of Identity, Contradiction, and 
 Excluded Middle, otherwise than negatively — unless, indeed, 
 with Dean Mansel, he regarded all analytical or explicative 
 judgments as reducible to concepts — all veritable judgments 
 being thus synthetical or ampliative. A circumstance 
 already alluded to might almost lead us to think that such 
 was his real opinion. In the twelfth of his Lectures on Logic 
 he begins by giving two distinct divisions of concepts, viz. 
 into Identical (or rather Similar or Cognate) and Different, 
 and into Congruent and Conflictive; but when he proceeds 
 to define a Judgment in the thirteenth Lecture, he explains 
 it as the recognition of a relation of congruence or conflic- 
 tion only, without taking any notice of the other relation of 
 cognateness or difference. If this similarity or cognateness 
 is the same with the partial identity which he has elsewhere 
 noticed as existing between a concept and each of its characters 
 (which it appears to be), all affirmative analytical judgments 
 express a relation of cognateness instead of a relation of con- 
 gruence: and in describing affirmative judgments as recogni- 
 tions of congruence only, Hamilton seems to be confining his 
 attention to those which are synthetical or ampliative. Other 
 passages of his descriptions, however, are, as we have seen, 
 not only applicable to analytical judgments, but apply to 
 them so exclusively that we might imagine that they were 
 the only kind of judgments which he recognized. A different 
 explanation of the application of the laws of Identity, Contra- 
 diction, and Excluded Middle to concepts may perhaps be 
 derived from the following passage: " A concept is a judg- 
 ment : for on the one hand it is nothing but the result of a 
 foregone judgment, or series of judgments, fixed and recorded 
 
LOGIC. 145 
 
 in a word — a sign — and it is only amplified by the annexation 
 of a new attribute throngh a continuance of the same process. 
 On the other hand^ as a concept is thus the synthesis or com- 
 plexion, and the record I may add, of one or more prior acts 
 of judgment, it can, it is evident, be analyzed into these 
 again. Every concept is, in fact, a judgment, or a fasciculus 
 of judgments — ^these judgments only not explicitly developed 
 in thought, or formally expressed in terms." ' This observa- 
 tion may justify the statement that the laws of Identity, 
 Contradiction, and Excluded Middle, are the fundamental 
 laws of all three operations of thought ; but then it is only 
 through their application to judgments that we can bring 
 concepts under their authority. 
 
 The theory of judgments has been already examined, but 
 the question remains. How can these three laws of thought be 
 applied to them? The law of Identity, we have been told, is 
 the principle of all logical affirmation, but it applies only to 
 analytical judgments. The law of Contradiction, we have 
 heard, is the principle of all logical negation. Its application 
 is equally limited. The law of Excluded Middle has been 
 described as the principle of disjunctive judgments, but it 
 clearly applies only to those disjunctive judgments which are 
 
 ' Lect. iii. 117. This description seems to me unsatisfactory. Take 
 the concept Man, which is generally represented as equivalent to the com- 
 bination Eational-Animal. According to Hamilton, this concept is the 
 result and record of a judgment in which we affirmed a relation between 
 the concepts Rational and Animal ; and that relation is now implicitly 
 contained in the concept Eational-Animal (or Man), and can be extracted 
 from it by analysis. What then was the relation in question ? Was it. 
 All fiationals are Animals, Some Eationals are Animals, All Animals are 
 Rational, or Some Animals are Rational? Any one of these four judg- 
 ments would have led us to form the concept or combination Rational- 
 Animal, and that concept would be exactly the same in whichever of 
 these modes it was formed. How, then, can we, by a mere analysis of the 
 concept as it now exists in the mind, discover any of these judgments in it? 
 
 L 
 
146 SIR WILLIAM HAMILTON. 
 
 analytical. It shows the truth of a disjunctive judgment of 
 the form Every B is either C or non-C, but it has no bearing 
 on the truth or falsity of a disjunctive judgment of the form 
 Every B is either C or D, where D is a term really distinct 
 from non-C. It is true that these laws appear to have a wider 
 scope in the case of judgments than of concepts. Besides their 
 negative use in excluding absurd or self-contradictory judg- 
 meutSj they have a positive use in showing the truth of ana- 
 lytical judgments. But what of the most important class of 
 judgments — the synthetical or ampliative ? Are we to exclude 
 these from our catalogue of " logical affirmations " and " logical 
 negations" ? or can they be brought in some indirect manner 
 under the primary logical laws? This difficulty was not un- 
 noticed by Sir William Hamilton. In one of his latest writings, 
 when pointing out the defects of these laws (which, as already 
 remarked, he regards as different phases of the same law), as a 
 criterion of truth, he says, " 1. It is negative, not positive. It 
 may refute, but it is incompetent to establish. It may show 
 what is not, but never of itself what is.' It is exclusively logical 
 or formal, not metaphysical or real. It proceeds on a necessity 
 of thought, but never issues in an ontology or knowledge of 
 existence." Again, " 3. It is explicative, not ampliative. It 
 analyzes what is given, but does not originate information or 
 add anything, through itself, to our stock of knowledge. 
 4. But, what is its principal defect, it is partial, not thorough- 
 going. It leaves many of the most important problems of 
 our knowledge out of its determination, and is therefore 
 all too narrow in its application as an universal criterion or 
 instrument of judgment." ^ And in another passage he says 
 that thought under this condition of non-contradiction is 
 
 ' This would seem even to go beyond what I have said in the text, and 
 to deny its use in showing the truth of affirmative analytical judgments. 
 2 Lect. ii. 524. 
 
LOGIC. 147 
 
 " merely explicative or analytic," ' and cannot therefore (we 
 may presume) give rise to synthetical judgments. Both these 
 passages, however, were written long after the Lectures on 
 Logic ; and the distinction between analytical and synthetical 
 judgments not having been noticed in these Lectures, the 
 difficulty does not appear to have then presented itself to the 
 author; while we can hardly expect to find a satisfactory 
 solution of it in the subsequent fragmentary notices, which in 
 their existing shape were probably not intended either for 
 delivery or publication. One solution, indeed, readily suggests 
 itself. The only logical judgments, it may be said, are 
 analytical judgments, and these result directly from the three 
 primary laws of thought. In all synthetical judgments some 
 other faculty intervenes, and, as regards their formation, they 
 are not within the province of Pure Logic. But Pure Logic 
 must nevertheless deal with them in their character of products^ 
 because they furnish materiils for the third great operation of 
 thought — reasoning; and the reasonings for which they 
 supply the premisses, depend as exclusively on the primary 
 laws of thought as if the premisses were analytical. Non-logi- 
 cal judgments must therefore be taken into account in Logic, 
 because they supply materials for logical reasonings ; but non- 
 logical (or inconclusive) reasonings should be omitted from 
 Logic, because they do not furnish materials lor any higher 
 operation of thought. I have not, however, found this ex- 
 planation in Sir William Hamilton's writings, while there are 
 several passages, especially in his Lectures on Logic, which 
 would seem to imply that all judgments are analytical or 
 explicative, and thus come directly under the primary laws 
 of thought. For instance, when comparing the compre- 
 hension and extension of concepts, he says, " The quantity 
 of extension is a creation of the mind itself, and only created 
 ' Discussions, 603. 
 L 2 
 
148 SIR WILLIAM HAMILTON. 
 
 through, as abstrneted from, the quantity of comprehension; 
 whereas the quantity of conaprehension is at once g-iven 
 in the very nature of things. The former quantity is thus 
 secondary and factitious, the latter primary and natural/'' If 
 this be so, it is only when the comprehension of one notion 
 includes that of another, that we can judge that the extension 
 of the former is contained in that of the latter; and therefore 
 it is only in the case of analytical judgments that we can 
 affirm the total or partial coincidence of the extensions of the 
 subject and predicate. This would exclude affirmative syn- 
 thetical judgments altogether, unless we suppose that Hamil- 
 ton was speaking of the relations between the two quantities 
 only in so far as they can be determined by pure thought, 
 without any reference to experience. 
 
 Another solution, however, is suggested in Hamilton's 
 Lectures, and has been apparently adopted by Dean Mansel, 
 whose exposition of a similar theory of Pure Logic, in the 
 sixth chapter of his Prolegomena Logica, will be found in 
 some respects superior to that of his master. (Hamilton has 
 referred to this work in terms of approval.) " If two 
 notions," says Hamilton, "be judged congruent — in other 
 words, be conceived as one'' — (and he has just told us that this 
 occurs in every judgment) "this their unity can only be 
 realized in consciousness, inasmuch as one of these notions is 
 viewed as au attribute, or determination, of the other. For, 
 on the one hand, it is impossible for us to think as one, two 
 attributes — that is, two things viewed as determining, and 
 yet neither determining or qualifying the other; nor, oa 
 
 ' Lect. iii. 218. The dependence of the quantity of extension on that 
 of comprehension is, however, a common doctrine of logicians who 
 have frequently assumed in their expositions that all judgments are 
 analytical. Hamilton may not impossibly have taken this doctrine from 
 them without sufficient examination, and without being himself influenced 
 by it in any other portion of his philosophy. 
 
LOGIC. 149 
 
 the other hand, two subjects— that is, two things thought as 
 determined, and yet neither of them determined or quahfied 
 by the other. For example, we cannot think of the two 
 attributes electrical and 2)olar as a single notion, unless we 
 convert one of these attributes into a subject to be determined 
 or qualified by the other ; but if we do — if we say, what is 
 electrical is polar, we at once reduce the duality to unity — we 
 judge that polar is one of the constituent characters of the 
 notion electrical, or that what is electrical is contained under 
 the class of things marked out by the common character of 
 piolariiy." ' It is true that the alternative in this last sentence 
 may suffice to distinguish Hamilton's doctrine from that of 
 Mansel, though, if the relation between the quantities of 
 extension is determined by that which exists between the 
 quantities of comprehension, it would not do so. To under- 
 stand the passage rightly, however, I think we must regard 
 the word notion as used in the vague signification abeady 
 alluded to. If that word is employed in its strict sense, it 
 is obvious that my notion of electrical or electricity could not 
 have any constituent character which I was not previously 
 aware of. Its constituent characters are its comprehension ; 
 and if polarity is not included in this comprehension, it is not 
 one of the constituent characters of the notion electrical. But 
 the meaning seems to be, that we first recognize polarity as 
 one of the constituent characters of the thing (or class of 
 things) electrical or electricity : and then, since we always 
 endeavour to make our notions or concepts correspond with 
 the things to which they are applicable, we reform or enlarge 
 our notion of electrical or electricity by adding to it the 
 attribute or notion of polarity. What was formerly thought 
 as electrical is now thought ^s, polar -electrical ; and the judg- 
 ment lohat is electrical is polar has been transformed into what 
 1 Lect. iii. 227. 
 
ISO SIR WILLIAM HAMILTON. 
 
 is polar-electrical is polar, the truth of which latter judg- 
 ment is at once made manifest by the law of Identity. In 
 fact, by this amplification of the concept electrical (and 
 concepts may retain their names notwithstanding the en- 
 largement of their comprehensions) the synthetical judgment 
 has been converted into an analytical one. Synthetical judg- 
 ments are thus only analytical judgments in the making, and 
 tJie ultimate end of all processes of reasoning is the reforma- 
 tion and amplification of our concepts.' If it is objected to this, 
 tha* when the judgment vias first formed, its truth must have 
 been arrived at in some other way than by the law of 
 Identity, the answer would probably be, that the process by 
 which it was arrived at was not one of pure thought, and that 
 as soon as the judgment what is electrical is polar came to 
 express a veritable operation of thought, its truth became 
 manifest by means of the law of Identity alone. This theory, 
 however, not having been explicitly enounced by Hamilton, 
 need not be further discussed here. I will only say, that 
 granting that the two notions must become combined, in the 
 manner stated, in order to constitute a judgment, the combina- 
 tion may take place in a different way, which would leave the 
 distinction between analytical and synthetical judgments 
 unaffected. If instead of the subject becoming amplified by 
 the addition of the predicate, the predicate itself remaining 
 unaltered, the subject remained unaltered while the predicate 
 was amplified by the addition of the subject, the judgment 
 would still be synthetical, and the law of Identity would not 
 suffice to establish its truth. What is polar-electrical is polar 
 is a judgment which falls under that law ; but what is electrical 
 
 ' Neither Hamilton nor Mansel liave gone so far as this in any of their 
 published writings, and the last sentence is borrowed partly from Mr. 
 Lewes, and partly from Archbishop Thomson, the latter of whom has, to 
 a large extent, adopted the Hamiltonian view of Logic. 
 
LOGIC. 151 
 
 is polar-electrical Aocs not, except negatively. Yet in each of 
 these judgments the duality of the two notions electrical and 
 jaolar is equally reduced to unity. 
 
 The theory of the Quantification of the Predicate belongs 
 rather to reasonings than to judgments, because its principal 
 effects appear in the doctrine of the Syllogism. This, however, 
 is the most convenient place for giving some account of it. 
 
 In the four forms of categorical judgments or propositions 
 ordinarily recognized by logicians, which are denoted by the 
 letters A, E, I, and O, the subjects are quantified, but the 
 predicates are not ; and the latter might therefore appear to be 
 at first sight susceptible of being understood with two different 
 quantities, and thus in two different senses. For instance. 
 All B is C may be understood to mean either All B is all C or 
 All B is some C ; and No B is C may be understood to mean 
 either No B is any C or No B is some C Logicians had in 
 general laid down that All B is C meant All B is some C, and 
 that No B is C meant No B is any C. But this, Hamilton 
 thinks, may not have been the meaning intended by the 
 persons who used these forms of expression; while even if it 
 was, they should not be debarred from the use of other forms 
 of expression which would convey a different meaning. A man 
 may j udge, or wish to assert, that two classes are co-extensive. 
 Why not then permit him to affirm that All B is all C ? Or, 
 instead of denying that any B is a C, be may only wish to 
 deny that any B is some C; instead of denying, for instance, 
 that any man is an animal, he may wish to deny that any man 
 is some kind of animal — that any man is a quadruped. Then 
 why not permit him to say that No man is some animal ? 
 Carrying out this idea. Sir William Hamilton proposed to 
 
 * But surely no one would say No B is C if he only meant, or only 
 believed, that No B is some C. No Man is immortal, seems to me to be 
 quite as unambiguous a statement as, No man is any immortal. 
 
152 S/R WILLIAM HAA^ILTON. 
 
 increase the number of propositioual forms from four to eight, 
 which are thus expressed symbolically : — 
 
 (1) 
 
 All B is 
 
 all C denoted bj 
 
 th 
 
 5 letter U 
 
 (2) 
 
 All B is 
 
 some C 
 
 , 
 
 
 A 
 
 (3) 
 
 SomeB 
 
 is all 
 
 , 
 
 
 Y 
 
 (4) 
 
 Some B 
 
 is some C 
 
 » 
 
 
 I 
 
 (5) 
 
 No Bis 
 
 any 
 
 » 
 
 
 E 
 
 (6) 
 
 No B is 
 
 some C 
 
 , 
 
 
 1) 
 
 (7) 
 
 Some B 
 
 is not any C 
 
 , 
 
 
 
 
 (8) 
 
 Some B 
 
 is not some C 
 
 , 
 
 
 , CO 
 
 Of these the affirmatives, in fact, express equations, and the 
 negatives inequalities. Thus U may be written All B = all C, 
 and A may be written All B ;= some C All propositions 
 become simply convertible ; for the conversion of affirmatives 
 consists in merely writing the same equation in a different 
 way, and inequalities are also convertible, since if B is not 
 equal to C, it follows that C is not equal to B. And since 
 they are simply convertible, they all reappear in their original 
 shape after reconversion. Thus A is convertible into Y, and 
 this Y can be reconverted into an original A, and then 
 again into Y, and so on as often as we choose to repeat the 
 process. When the predicates are thus quantified, the exten- 
 sions of the subject and predicate no longer stand to each other 
 in the relation of whole and part. They are always (in affirma- 
 tive propositions) equal, or rather identical. This alteration 
 gives a completely new direction to the doctrine of the Syllo- 
 gism. The number of legitimate modes in each figure^ is aug- 
 mented to thirty-six, of which twelve are affirmative and twenty- 
 
 ' These equations seem to express relations of extension only, whereas 
 the formula of the law of Contradiction for instance is only true of com- 
 prehensions. See note, p. 143. 
 
 - Hamilton, however, rejects the fourth figure on the ground that it is 
 merely the first figure with the premisses transposed, and the immediate 
 conclusion converted. Thus EIO of the fourth figure is but a bad way 
 of writing lEi; of the first. 
 
LOGIC. I S3 
 
 four negative. The latter may be derived from the former by- 
 changing the affirmative copula of each premiss successively 
 into a negative copula, and making the same change in the 
 •onclusion.' The twelve affirmative modes are derived from 
 the sixteen pairs of affirmative premisses by rejecting those in 
 which an undistributed middle occurs, and supplying the 
 proper conclusion to the remaining pairs. The pair of pre- 
 misses II involves an undistributed middle in every figure. 
 The pairs lA^ YA and YI do so in the first figure, and those 
 which do so in the other three figures will be found by per- 
 forming the conversion or conversions necessary to change the 
 illegitimate pairs lA, YA and YI from the first into the 
 other figures. For every syllogism in the first figure, whether 
 good or bad, has its exact counterpart in each of the other 
 three. By simply converting the major premiss we obtain a 
 precisely equivalent syllogism in the second figure; by simply 
 converting the minor premiss we obtain one in the third; and 
 by simply converting both premisses one in the fourth. The 
 real number of valid modes would thus seem to be thirty-six 
 rather than 144, though there are four ways of stating each 
 of these thirty- six ; and the letters standing for the syllogism 
 will sometimes diffiir with the mode of stating it. Thus 
 AAA of the first figure — the Barbara of the Aristotelians — 
 becomes YAA in the second, AYA in the third, and YYA in 
 the fourth, figures respectively. The whole scheme is worked 
 out by a series of operations resembling those of algebra. It 
 will be seen, however, that two of the new propositional forms, 
 Y and t], are merely two new modes of expressing the old ones 
 A and O. "We can convert A into Y, and Y again into A, 
 thus proving the virtual identity of the two ; and, indeed, no 
 
 ' Where both premisses are negative, no conclusion can be draw u ; as 
 is also the case where the middle term is undistributed. To this extent 
 the Hamiltonian Logic agrees with the Aristotelian. 
 
154 SIR WILLIAM HAMILTON. 
 
 one could doubt that All B = some C aud some C = all B 
 represent the very same equation written in two different 
 ways. The same observation applies to 17 and O ; and on the 
 identity of these two forms with the other two recognized by 
 all logicians, two counter-arguments for and against their 
 admissibility into Logic are based. The Hamiltonian asks. 
 Why not permit me to make in one form the very same 
 assertion that I must confessedly be allowed to make in 
 another ? The Aristotelian asks, Why, when I am trying to 
 reduce all propositions to the smallest number of simple forms, 
 should I admit two new ones which assert nothing that 
 cannot be equally asserted by the old ones in common use ? 
 And here a very curious cross-argument might arise. The 
 Hamiltonian might say. You ought to admit the two new 
 forms, because they enable you to bring at once under the 
 Dictum, de omni et de ntdlo, syllogisms which you are only 
 able to reduce to that principle by the tedious and roundabout 
 process of rednctio ad impossibile. The Aristotelian could 
 answer, You ought not to admit them, because you reduce 
 all syllogisms to a series of simple equations, and every con- 
 * sequence that arises from such equations when written in one 
 order equally follows from them when written in the other. 
 No algebraist was ever yet assisted in solving a problem 
 by writing his fundamental equation mx = ny instead of 
 ny = mx. As soon as one quantity is expressed in terms of 
 the other, no further transformation of the equation is re- 
 quired ; and this is done when we put the proposition, as 
 expressed in ordinary speech, into either of these logical forms. 
 It is obvious to remark that this quantification of the 
 predicate is only applicable to its extensive quantity, though 
 Hamilton's language might sometimes lead the careless reader 
 to suppose the contrary. Every concept employed in a 
 logical pi'oposition is taken in its whole comprehension. 
 
LOGIC. 155 
 
 When I say Negroes are some Men, I mean that Negroes are 
 some of the beings which possess all the attributes included 
 in the comprehension of the concept Man ; and if I said that 
 Negroes are all Men, the word '' all " would not be used to 
 imply that Negroes possessed all the attributes included in 
 the comprehension of the concept Man (which would be 
 equally asserted if the predicate was quantified particularly or 
 left unquantifi.ed), but to imply that Negroes included the 
 whole extension of the concept Man. If I meant to afl5rm of 
 Negroes a part of the comprehension of the concept Man only, 
 I would not employ the term Man, but some other term or 
 terms connoting the particular part of the comprehension 
 which I desired to predicate. I would say, for instance, that 
 Negroes were bipeds, or mammals, or vertebrates, or animals, 
 or organized beings, as the case might be; but if I said they 
 were men, I could only be understood as asserting that the 
 whole comprehension of the concept Man was to be found in 
 them. When, therefore, we find Hamilton using such ex- 
 pressions as. All Man is some Animal, we must not suppose 
 that by the use of the singular number and the capital letter 
 he means to direct attention to the comprehension instead of 
 the extension — to the concept in the mind instead of the class 
 of things which come under it. In fact, if the signs of 
 quantity could be taken in connexion with comprehension, 
 the proper expression for the last-mentioned proposition would 
 be. All Animal is some Man — meaning that the whole com- 
 prehension of the concept Animal is included in, and forms a 
 part of, the comprehension of the concept Man. Sir William 
 Hamilton has never given this meaning to his quantified 
 prepositional forms, and it would be a very wide departure 
 from common language to do so. All Man is some Animal 
 with him means (as in more than one passage he has stated) 
 All (class) Man is some (class) Animal, not All (concept) Man 
 
156 SIR WILLIAM HAMILTON. 
 
 is some (concept) Animal. The theory of the quautificatioa 
 of the predicate is for this reason somewhat difficult to re- 
 concile with the passages in Hamilton's works, in which he 
 describes judgments as arising from the comparison of con- 
 cepts, and as consisting in the recognition of a relation of 
 congruency, or even of whole and part, between them. It is 
 to be recollected, however, that all these passages were 
 written before the theory of the quantification of the predicate 
 was formally enounced by the author, and I have little doubt 
 that had he been able to revise his Lectures oq Logic, his 
 theory of Judgments would have been entirely rewritten. 
 
 It should be added that in his Propositional Forms, Sir 
 William Hamilton thinks " some " should be used in the 
 sense of some only instead of some at least} For if All Bs 
 are Cs, they must either be all Cs or some Cs only ; and since 
 in the former case I ought to quantify the predicate univer- 
 sally, the particular quantification ought to be limited to the 
 case in which All Bs are some Cs only. Whenever we think 
 of the class as a whole, we should employ the term All ; and 
 therefore when we employ the term Some, it is implied that 
 we are not thinking of the whole, but of a part as contra- 
 distinguished from the whole — that is, of a part only. This, 
 as Sir William Hamilton points out, is not the meaning 
 which logicians generally attach to the word " some ;" and 
 for this reason the Propositional Form, which Hamilton calls 
 
 A, for instance, does not j)recisely correspond to that which 
 the Aristotelians denote by the same letter. The proposition 
 All B is C with the Aristotelians is consistent with the co- 
 extensiveness of the two classes B and C, though it does not 
 assert it. It is thus consistent with the proposition All C is 
 
 B, or with the U of Hamilton. But Hamilton's proposition 
 All B is some C means that All B is some C only — that C is a 
 
 ' Discussions, p. 690, text and note. 
 
LOGIC. 157 
 
 larger class in which B is included — and it is therefore incon- 
 sistent with the Aristotelian All C is B, as well as with both 
 the Hamiltonian propositions All C is all B, and All C is some 
 B. Thus A and A converse, with Hamilton, cannot both be 
 simultaneously true. Again, if we take the form O, Some B is 
 not any C would, if some is taken to mean some only, imply 
 that there are other Bs which are Cs — an assertion which is not 
 implied by the Aristotelian form. Some B is not C, though it 
 is consistent with it. Accordingly Hamilton recognizes an 
 inference from O to I, and vice versa, which he terms Inte- 
 gration. But, curiously enough, the two systems coincide 
 with respect to the form I. Some B only is C, would indeed 
 imply that there are other Bs which are not Cs ; but the 
 Hamiltonian form is. Some B (only) is some C (only), which 
 is quite consistent with the other Bs being other Cs. The 
 second only thus in fact neutralizes the effect of the first.' 
 Hamilton, however, has not worked out the results of the 
 quantification of the predicate from this point of view, nor 
 has he given a complete sketch of the alterations which would 
 be introduced into the rules of Logic by employing some in 
 the sense of some only. Indeed this meaning of some does 
 not occur in his Lectures on Losic. 
 
 I have already noticed some of the grounds assigned for 
 the rejection of the new forms Y and t]. I may add that U 
 and Q) have not escaped criticism. Of o) it has been said that 
 it really asserts nothing, for though some Bs are not some 
 Cs, still the very Bs, of which we are thinking, may be other 
 Cs, and the two classes, B and C, may even be co-extensive. 
 Such a proposition, moreover, appears to be meaningless 
 when considered in comprehension. It neither affirms nor 
 
 Hamilton, however, has not observed this fact, which seems to interfere 
 with his new inference of Integration when drawn from I to O instead of 
 fnim to I. 
 
IS8 SIR WILLIAM HAMILTON. 
 
 denies that the some Bs which form its subject possess the 
 attributes included in the comprehension of the concept C. 
 Judgments — according at least to Hamilton's earlier theory — 
 arise from recognizing the congruent or conflictive character 
 of the concepts which form the subject and predicate : but 
 the judgment. Some B is not some C, does not give us the 
 smallest information as to whether the concepts B and C are 
 congruent or conflictive. This last objection would, indeed, 
 be removed by employing the word "some" in the sense of 
 some only, as Hamilton proposes. If it is some Bs only that 
 are not identical with the particular part of C of which we 
 are thinking, there must be other Bs which are identical with 
 (or contained in) that part of C. But a new objection now 
 arises, namely, that what is really asserted by a> (on this inter- 
 pretation of it), is that Some (other) Bs are some Cs, and that 
 <a is therefore no more than a different way of writing I. 
 Again, U has been objected to c>n the ground that it is a com- 
 pound, not a simple proposition ; that it includes two dis- 
 tinct assertions, which may be made the foundation of two 
 different trains of reasoning — that All men are all rational 
 animals, for instance, is the precise equivalent of the two pro- 
 positions. All men are rational animals, and All rational animals 
 are men. Hamilton's answer to this objection is not very 
 satisfactory. Applying his own system of quantification, he 
 substitutes for the two propositions in question. All men are 
 some rational animals, and All rational animals are some men 
 (of course his opponent could not quantify either of the pre- 
 dicates with the word All, for that would be to admit the 
 prepositional form U) and then taking some in the sense of 
 some only, he shows that the two alleged components of his 
 proposition U are in fact inconsistent with each other, and 
 cannot be united in thought.' But as the Aristotelian does 
 
 ' This seems to be involved in his answer to Mr. De Morgan, Discus- 
 
LOGIC. 159 
 
 not use the word some in the sense of some only, but of some 
 at least, the two propositions in question would, notwith- 
 standing the employment of that word in quantifying their 
 predicates, be quite consistent with each other, and they seem 
 to make up between them the whole of what is asserted 
 by Hamilton's U. I do not think that Hamilton has any- 
 where asserted that All B is some C ceases to be a simple 
 proposition when we use some in the sense of some at least.' 
 In fact there would be much more reason for maintaining 
 that it becomes a compound proposition if we use some 
 in the sense of some only. But even conceding that All B 
 is (some) C, as employed by the Aristotelians, is a compound 
 proposition, this would not remove the present objection ; for 
 if U is made up of two compound propositions, it is even more 
 objectionable than if it was made up of two simple ones.^ 
 
 sions, p. 688 ; but possibly Hamilton intended tbis answer as a mere 
 argumentum ad hominem. Mansel adopts a similar mode of reasoning. 
 Prolegomena Logtca, p. 268. 
 
 ' Perhaps he would have sought to evade the difficulty thus. The 
 Aristotelian proposition, All B is some C (at least) is equivalent to the two 
 Hamiltonian propositions, All B may be all C and All B may be some C 
 (only;. The former of these is TJ and the latter A ; for " may be " must 
 he treated in Logic as an affirmative copula. The Aristotelian A is thus a 
 compound, the Hamiltonian U being one of its components, and conse- 
 quently any attempt to deduce the Hamiltonian U from two Aristotelian 
 As (with the terms transposed) involves a circular argument. 
 
 ^ Hamilton asks why should All B is all C be treated as a compound 
 proposition when it is admitted that All B is some C is not so? The 
 Aristotelian, I believe, could answer the question. As AH B is all C is 
 made up of All B is C and All C is B, so All B is some C is made up of 
 All B is C and Some G is B. But while the former pair are two distinct 
 propositions not inferrible from each other, one of the latter pair can be 
 derived from the other by conversion, and therefore the two component 
 propositions are not distinct and independent. To justify this answer, how- 
 ever, it should be laid down that the predicate of a proposition never has 
 any quantity — that is, while it remains a predicate — and that it acquires 
 a quantity for the first time when it is transformed into a subject by 
 
i6o SIR WILLIAM HAMILTON. 
 
 Hamilton believed that tbis theory of the quantification of 
 the predicate involved the true explanation of the logical 
 nature of an Inductive argument. The form of a logical 
 Induction is in his opinion as follows : — 
 
 X, y, z, &c. (enumerating the individuals) are Cs, 
 X, y, z, &o. (enumerating the individuals) are all Bs, 
 Therefore All Bs arc Cs. 
 That this reasoning is valid cannot be doubtedj though it 
 could hardly occur in practice, owing to the difficulty of 
 making an individual enumeration of all the Bs. Nor if it 
 did occur, would it be of much value, since the conclusion 
 would be little more than a short way of writing the major 
 premiss. The use of a proposition of the form All Bs are 
 Cs, is in general to tell us that something that we have not 
 already ascertained to be a C is so — which it does when we 
 have first satisfied ourselves that the thing in question is a 
 B, which fact is not always obvious. But if we arrived at 
 the proposition All Bs are Cs, by the reasoning here set out, 
 we could never discover as a new fact that anything was a 
 B ; for a knowledge of every individual B is presupposed by 
 the reasoning. Neither from our recognition that a given 
 thing was a B, could we be led as a new fact to conclude that 
 it was a C ; for we could not draw that conclusion until we 
 were not only individually acquainted with every one of the 
 Bsj but had likewise ascertained that each of them was a C 
 conversion. The quantity which is thus acquired is particular when the 
 convertend is affii-mative, and universal when it is negative. This, I 
 believe, is the true meaning of the assertion that the predicate of an 
 affirmative judgment is particular, and that of a negative universal — 
 assertions which can only be understood in connexion with conversion. 
 
 ' Suppose, in fact, that this (so-called) induction was followed by a 
 deduction — 
 
 All Bs are some Cs, 
 
 /3 is a B, 
 
 /3 is a C. 
 It is here plain that /3 must have been one of the individuals included 
 
LOGIC. i6i 
 
 That the inductions of the Physical or Empirical Sciences 
 are not reducible to the Hamiltonian form, our author seems 
 to admit J and it can hardly be said that the form in ques- 
 tion is in common use. Its only use would therefore seem to 
 consist in pointing out the insufficiency of the Aristotelian 
 table of Syllogisms (and consequently of the Aristotelian list 
 of forms of propositions) by giving an instance of a valid 
 mode of reasoning which cannot be reduced to them. But 
 the Aristotelian would probably reduce it to a Syllogism in 
 Barbara by writing the minor premiss, All B is oc, y, z, &c. 
 Whether this reduction is satisfactory I must leave to the 
 reader.' 
 
 The reduction of all judgments or propositions to equations 
 (or rather identifications) between the subject and predicate 
 
 in our x, y, z, &c., since othei-wise it would not be true that x, y, z, &c. 
 are all the Bs. The entire reasoning would therefore run as follows : — 
 
 X, y, z, |8, &c. ai'e some Cs, 
 X, y, z, 3, &c. are all Bs. 
 .'. All Bs are some Cs. 
 is a B, 
 .-. ^ is a C. 
 And we have got back to (a part of) what was stated, not in general terms 
 or even specifically, but individually, in the major premiss of the induc- 
 tion. Whatever be the force of the objection to the Syllogism in general 
 as containing a Petitio Principii, there can be no doubt of the futility of 
 this kind of argument. In fact the major premiss o£ the induction sums 
 up a number of singular propositions, the truth of each of which must 
 have been separately inquired into and ascertained, and one of these 
 singular propositions must have been |3 is a C, which is the judo-ment 
 or proposition finally arrived at by this pretended process of reasoning. 
 ' The best mode of reducing it would perhaps be as follows : — 
 Every B is either x or y or z, &a., 
 ■' X and -y and 2, &c. are Cs, 
 .'. Every B is a C. 
 
 This is a kind of disjunctive reasoning of which the Aristotelian 
 logicians seem to have given a sufficient account. 
 
i62 S/R WILLIAM HAMILTON. 
 
 renders the application of the laws of Identity, Contradiction, 
 and Excluded Middle to the Syllogism more easy than under 
 the Aristotelian system. The same result is still more evi- 
 dent in the case of immediate inferences, such as conversion ; 
 and therefore as regards the third logical operation — inference 
 or reasoning — we do not meet with the same difficulties that 
 were experienced in the case of concepts and judgments. No 
 reasonings being admitted except those which are formally 
 conclusive, thought is here really analytical or explicative. 
 The conclusion contains nothing that is not contained in the 
 premisses — not, indeed, in the major premiss, as some oppo- 
 nents of the Syllogism allege, but in tlie two premisses taken 
 together — and the laws of Identity, Contradiction, and Ex- 
 cluded Middle, being the fundamental laws of explication or 
 analysis, seem sufficient to account for the whole process. 
 
 Such is the Hamiltonian Logic. Its deficiencies, as already 
 remarked, seem chiefly attributable to the fact that its author 
 had not fully elaborated his logical theory when he wrote his 
 Lectures on Logic, and that his subsequent writings on the 
 subject took the shape of fragments — some of them post- 
 humous—instead of a connected treatise. It has been rarely 
 accepted in its entirety, but a large number of subsequent 
 logicians have availed themselves of considerable portions of 
 it. Thus Archbishop Thomson accepts Hamilton's addi- 
 tional affirmative forms of Propositions U and Y, while re- 
 jecting the negative forms t) and w, and he has, in consequence, 
 developed a Syllogistic scheme differing both from that of 
 the Aristotelians and that of Hamilton. No part of Hamil- 
 ton's system required the revising hand of the master more 
 than his Logic. If he had signalized the distinction between 
 Analytical and Synthetical judgments, which in his later 
 writings at least was clearly recognized, and at the same time 
 consistently carried out his statement that comprehension 
 
LOGIC. 163 
 
 and extension are not two co-ordinate properties of the con- 
 cept, but that comprehension is the primary one on which 
 extension depends — that it is, in fact, the concept itself, 
 while extension (at least real extension) is a contingent attri- 
 bute of it — the Hamiltonian Log-ic must to a great extent 
 have taken a new form, and the exposition of the theory of 
 judgments would have been cleared of the ambiguities, diffi- 
 culties, and inaccuracies which it now presents. It is, indeed, 
 to Hamilton's life, rather than to his philosophy, that we must 
 look for the explanation of these defects. 
 
 It will be seen from the foregoing sketch that incomplete- 
 ness is one of the characteristics of the Hamiltonian Philosophy 
 generally. For this, perhaps, the author was not to blame; 
 and an incomplete system, provided it contains numerous 
 points of interest and importance, is often more useful in 
 arousing speculation than a complete one. When a system is 
 completed its weak points are usually more or less concealed. 
 Readers are either captivated by its symmetry, and accept it 
 as a whole ; or else, satisfied that as a whole it is erroneous, 
 they reject it, without waiting to discover and signalize 
 the joints in its harness. In an incomplete system, on the 
 other hand, defects and inconsistencies generally appear 
 on the surface: but. if it has a real value which impresses 
 itself on the student, the faculty of thought will be stimu- 
 lated either to reconcile these inconsistencies and complete 
 the system, or else to use the valuable materials collected by 
 the author in the construction of a new system presumably 
 different from his own. Accordingly, I believe that no 
 philosophic writer of the present century has had the same 
 influence in cultivating metaphysical speculation as Sir 
 William Hamilton, nor perhaps is there any other in whose 
 works so many important philosophical problems have been 
 mooted, if not solved. " Prudens interrogatio," says Bacon, 
 
 M 2 
 
1 64 SIR WILLIAM HAMILTON. 
 
 "est dbnidium scientice ;" and if Hamilton does not always 
 propound his theories in the form of interrogations^ they are 
 not (even when erroneous) less valuable as steps towards a 
 final solution. No Idealist, for instance, will deny that 
 philosophy has gained much by having the problem of the 
 external world set before us in the manner in which Sir 
 William Hamilton has stated it. Everything seems now 
 prepared for a final issue, and even if that issue should prove 
 unfavourable to Natural Realism, to Sir William Hamilton 
 will belong the credit of having compelled philosophers to 
 decide it, and of having stated the case on which their decision 
 was given. A philosopher who has left behind him nothing 
 but well-stated problems may have rendered the world a greater 
 service than one who has only attempted to furnish solutions, 
 to say nothing of one who has confined himself to descrip- 
 tion and illustration. This, I think, vvas Hamilton's greatest 
 merit,' and in dealing with his several theories I have gene- 
 rally aimed at stating them rather in the form of hypotheses, 
 pointing out some of the arguments in favour of each hypo- 
 thesis and some of the objections against it. And perhaps 
 if the theories put forward by the various schools of Psycho- 
 logy were regarded as hypotheses, and if inquirers attempted 
 to trace out the consequences of two or more rival hypotheses 
 — not for the purpose of refutation, but of bond fide investi- 
 gation — pointing out everything favourable and unfavourable 
 to each, but without decidedly committing themselves to 
 either, a final decision on their validity might be sooner 
 arrived at. Physical investigators often do this. Why 
 should not Psychologists? 
 
 ' Hamilton himself regards the pursuit of truth, as a mental exercise, 
 more valuable than the truth itself when discovered. See the first of hia 
 Lectures on Metaphysics. To have induced many inquirers to join in this 
 pursuit would therefore be, in his opinion, the highest success that a 
 philosiiplicr could aim at. 
 
APPENDIX. 
 
 Hamiltonian Liteeattjbe. 
 
 Such has been the impulse which Hamilton has given to speculativa 
 thought in this country that to enumerate the various works in which 
 some portions of his system have been vindicated or criticized — adopted or 
 rejected— would require an erudition almost equal to his own. The 
 reader, however, who desires to pursue the theories which he advocated to 
 their latest developments, and to study the principal animadversions 
 which have been made on them will obtain some information from the 
 following list, which makes no pretension to completeness. 
 
 The great criticism on the Hamiltonian system is the late Mr. J. S. 
 Mill's Examination of Sir William Hamilton's Philosophy. The 
 first edition of this work appeared in 1865. The fourth edition — the 
 last during the author's lifetime — was published in 1872. The later 
 editions are much enlarged and improved, and contain answers to a 
 number of writers who had defended Sir William Hamilton against the 
 attacks made upon him in the first edition. This book has been frequently 
 referred to in the text, even in some passages where Mr. Mill was not 
 named. 
 
 Sir William Hamilton's most illustrious disciple was the late Dean 
 Mansel, who, however, sought to unite with the Hamiltonian System 
 some Kantian elements. His notes to his edition of Aldrich's Logic and 
 his Prolegomena Logica (1851; but a considerably enlarged edition 
 appeared in 1860) chiefly expand Hamilton's views on the subject of 
 Logic. The latter, however, contains an able discussion on the subject of 
 Necessary Truths, including Hamilton's doctrine of Causality. Dean 
 Hansel's Bampton Lectures on The Limits of Religious Thought (1858) 
 are intended as a development of the Hamiltonian doctrine of the Absolute 
 and Infinite. Much of the Hamiltonian system is incorporated in his Meta- 
 physics ; and after the appearance of Mr. Mill's Examination he published 
 The Philosophy of the Conditioned, which was intended as a reply to it. 
 He subsequently published an article on the same subject in the Contem- 
 
166 APPENDIX. 
 
 porary Seview for September, 1867, which was answered by Mr. Mill in 
 the last edition of liis JSxamination. 
 
 In addition to a vast number of reviews (manj' of which are referred to 
 in the note), Mr. Mill, in the later editions of his Examination, mentions 
 the following works as called forth b}' his controversy with Sir William 
 Hamilton in addition to Mansel's Fhilosopki/ of the Conditioned. (1) 
 The Battle of the Two Philosophies, hy an Inquirer. (2) A-U Examina- 
 tion of J. S. Mill's Philosophy, by Dr. M'Cosh, who afterwards contri- 
 buted an article on the same subject to The British and Foreign 
 Evangelical Review for April, 1868. (3) A Criticism of John. Stzcart 
 Mill's Pure Idealism, by Mr. H. F. O'Hanlon. (4) A Commentary on 
 Kanfs Critick of the Pure Season, by the Rev. J. P. Mahaffy. This 
 work is a translation of Professor Kuno Fischer's Commentary, with an 
 Introduction by Piofessor Mahaffj, in which the Hamilton-Mill con- 
 troversy is dealt with. (5) Recent British Philosophy, by Prol'essor 
 Masson. The last edition of this work, dated 1877, is somewhat enlarged. 
 He also refers to Mr. Alexander's Mill and Carlt/le, but that work seems 
 to relate more especially to Mr. Mill's own philosophy, an observation 
 also partly applicable to the works of Mr. O'Hanlon and Professor 
 Maliaffy. Mr. Mill also notices some criticisms comprised in Professor 
 Veitch's Memoir of Sir William Hamilton } To these I may add — 
 
 Sir William Hamilton . being the Philosophy of Perception ; an 
 Analysis, by Dr. J. Hutchinson Stirling. 
 
 Inquisitio Philosophica : an Examination of the Principles of Kant 
 and Hamilton, by Mr. M. P. Bolton. Both these works appeared in 
 Mr. Mill's life-time, and are referred to by him in the Preface to the later 
 editions of his Examination. 
 
 > He mentions also the following reviews : — Mill v. Hamilton, by Dr. 
 H. B. Smith, in the American Presbyterian and Theological Review 
 for January, 1866. A review of Mr. O'Hanlon's work in Blackwood's 
 Magazine for January, 1866. A review of Mdl's Examination in the 
 JJuhlin Review for October, 1865, signed R. E. G. Another in the Edin- 
 burgh Revieto for July, 1866. Another in the North British Review 
 for September, 1865, ascribed to Professor Fraser. One entitled Mill v. 
 Hamilton in the Fortnightly Revieto for July 15, 1865, by Mr. Herbert 
 Spencer. One in the Westminster Reiiew for January, 1866, ascribed 
 to the late Mr. George Grote. One in the North American Review for 
 July, 1866, and one by Dr. Ward in the Dublin Reviiw for October, 
 1871. Mr. Mill also refers to Dr. Ward's work on Nature and Grace. 
 
APPENDIX. 167 
 
 Kant's Critical Fhilosophy for English Readers, by the Kev. Pro- 
 fessoi' MahaflTy. In the first part of this work, which appeared during 
 Mr. Mill's life-time, but was not noticed by him, Professor Mahaffy 
 resumes the controversy from his former work, and replies to Mr. Mill's 
 strictures. There are some further observations in the second part. 
 
 Notes on Mill's Examination of Hamilton's Philosophy, by Thomas 
 Edwards. This work was published in Calcutta, thus affording evidence 
 of the wide-spread interest occasioned by the controvers}'. It appeared 
 in 1878. 
 
 Seligious Progress, Ly the Rev. Dr. M'lvor. In the notes to this 
 volume a more extreme theory of Natural Realism than that of Hamilton 
 is expounded, and the theories of Hamilton and Mansel are criticized. It 
 appeared in 1871. I have myself advocated a modified doctrine of Natural 
 Realism in a work on Space and Vision (1872). 
 
 Mill V. Hamilton, by T. Collyns Simon — an idealist of the Berkeleian 
 type. 
 
 Among the logical treatises most largely influenced by Sir William 
 Hamilton, and also containing criticisms on hia theory of Logic, I should 
 notice Archbishop Thomson's well-known Outline of the Laws of Thought. 
 Also Professor Spencer Baynes's Essay on the New Analytic of Logical 
 Forms. Of course almost every subsequent writer on Logic has had 
 occasion to refer more or less to the Hamiltouian doctrine. Some criticisms 
 on it will be found in my own Litroduction to Logic (1880). 
 
 I should not conclude this Appendix without noticing a pamphlet on 
 Sir William Hamilton by Dr. Thomas Maguire, which was published 
 several years before Mr. Mill's jExawjirea^iore; nor ought I to omit Dr. 
 Calderwood's Philosophy of the Infinite, published in Hamilton's life- 
 time. 
 
GLOSSARY OF PHILOSOPHICAL TERMS. 
 
 Absolute. This word has more than one meaning. Sir "William 
 Hamilton proposes to use it in the sense of that which is finished, 
 perfected, or completed; in contrast to the Infinite, which can never ha 
 completed. He notices as another meaning, the opposite of the Rela- 
 tive, viz., that which does, or at least can, exist out of relation, whether 
 to the thinking mind or to anything else. Other philosophers used the 
 terms Absolute, Infinite, and Unconditioned, as identical in meaning, 
 and as referring to the ultimate being or first cause. This employ- 
 ment of the term Hamilton thinks objectionable, though in arguing 
 against his opponents he finds himself occasionally compelled to adopt 
 it. In this third sense Absolute is opposed to Conditioned. 
 
 Absolute (Identity). Sir William Hamilton gives this name to the 
 system which holds that the thing which we perceive and the mind 
 which perceives it are both fundamentally the same thing, and that 
 the distinction which consciousness draws between them is illusory. 
 This thing is not regarded as either Mind or Matter, but as that 
 which sometimes appears as Mind and sometimes as Matter, both 
 appearances being in fact delusive. 
 
 Absteaction. The act by which our attention is converged on certain 
 parts of an object (or on the common parts of several objects), to the 
 exclusion of the rest ; or by which certain parts of an object are left 
 unattended to, the remainder occupying the mind exclusively. These 
 parts may be of two kinds, viz., integrant parts which are capable of 
 being perceived or imagined separately, as the arms and legs of a man, 
 which may be perceived or imagined apart irom the rest of his body ; 
 or else subjective parts (or modes) which can be considered separately 
 though they cannot be perceived or imagined by themselves, as the 
 shape, size, colour, or weight of a man. Hence Abstraction is divided 
 into Partial or Concrete Abstraction, and Modal Abstraction. It 
 is by Abstraction — especially Modal Abstraction— that concepts, 
 notions, or general ideas are formed. See Attention, 
 
 Accident. This word is occasionally used by Hamilton in the sense jf 
 
GLOSSARY OF PHILOSOPHICAL TERMS. i6() 
 
 quality, attribute, or propertj', as distinguished from subject or sub- 
 stance. Every subject or substance has accidents, and every accident 
 belongs to a subject or substance ; but it is only the accidents of which 
 consciousness takes direct cognisance. Accident is here used inter- 
 changeably with phEenomenon. 
 
 Affinity. The law of Affinity is the law by which similar or contrasted 
 ideas become associated together and thus capable of reproducing 
 each other. It occurs in Hamilton's Lectures, and seems to include 
 what in his Reid he calls the law of Repetition. See Association. 
 
 Ampliative (or Synthetical). These terms are applied to judgments 
 or propositions in which the comprehension, or connotation, of the 
 predicate is not altogether included in the comprehension, or conno- 
 tation, of the subject. (Instead of comprehension or connotation, 
 Hamilton sometimes uses the word intension, as afTording a more direct 
 contrast to extension). Such judgments are opposed to Analytical or 
 Explicative judgments or propositions in which the comprehension or 
 connotation of the predicate is identical with, or contained in, that of 
 the subject. Thus assuming that the comprehension, connotation, or 
 intension of the concept Man, or of the name Man, is Rational-Animal, 
 All men are rational. All men are animals, and All men are rational 
 animals, are Analytical or Explicative judgments or propositions ; 
 while All men are bipeds, and All men are mortal, are Ampliative or 
 Synthetical. A judgment or propopition may be Ampliative or Syn- 
 thetical although a part of the connotation of the predicate is included 
 in (or identical with) that of the subject, provided another part is not 
 so. Thus All men are two-legged animals, is an Ampliative or Syn- 
 thetical judgment or proposition, because although the comprehension 
 of the term Man includes the comprehension of the term Animal, it 
 does not, on the above assumption, include that of the term Two-legged. 
 
 Analytical (or Explicative). See Ampliative. 
 
 Appeehension. This word is used by Sir William Hamilton for a direct 
 and immediate presentation, perception, or intuition of an object, in 
 contrast to any mediate cognition, or mediate belief, in it, whether 
 arrived at by means of imagination or of inference. 
 
 Association (of Ideas). Association of ideas is that mental principle 
 which enables one mental state to recall another to the memory. 
 Thus the thought of Waterloo recalls to my memory at once the 
 thoughts Napoleon and Wellington, together with several otheis. In 
 this case the thoughts Napoleon and Wellington are both said to be 
 associated with the thought Waterloo ; and it is very possible that 
 the thoughts Napoleon and Wellington may also be directly associated 
 
\^o GLOSSARY OF PHILOSOPHICAL TERMS. 
 
 with eauh other, so that either will bring its companion into our 
 memory without referring to Waterloo at all. What ideas will be 
 associated in this manner depends very much on the experience and 
 habits of thought of the individual, hut in all minds some ideas 
 are associated with others. In tlie phrase Association of Ideas the 
 word ideas must be taken in its widest sense, as comprehending all 
 states of consciousness. 
 
 Attention. Attention, according to Hamilton, is not any special facult}', 
 or special act, but merelj' concentrated or vivid consciousness. We 
 can be conscious of probably six objects at once, and if so, whenever 
 we are conscious of less than that number, we may be said to be 
 attending to what we are conscious of. The term, however, is some- 
 times limited to cases in which consciousness is converged on two, or 
 at most three, objects, in which case it will be more vivid than when 
 extended to four or five. It is closel_v connected with Abstraction, 
 already considered ; for Abstraction may be described either as Atten- 
 tion directed to particular parts of an object, or as Non-attention to the 
 other parts of it. 
 
 Atteibute. This word is equivalent to quality or property. See 
 Accident. 
 
 Belief. This word frequently occurs in Hamilton, and not always in 
 the same sense. Any inexplicable conviction — any conviction for 
 which we can assign no reason — is ofted referred by him to Belief or 
 Feeling, as opposed to Knowledge or Cognition. On the other hand, 
 when a conviction falls short of certainty it is sometimes called Belief, 
 while when we feel perfectly certain we are said to know or cognise 
 the object. Again, when we are only convinced of the existence of a 
 thing, but have no knowledge of its properties (be3'ond those which 
 are implied in its name), we are sometimes said to believe in it, while 
 when our acquaintance with its properties is more extensive we are 
 said to know or cognise it. Thus we believe in a thing if we are con- ~ 
 vinced that it is, but only know it when we know how or why it is — 
 to adopt the Greek phrases, we may believe the to on, but only know 
 when we also attain the to Sioti. Belief, in Hamilton's writings, is 
 always opposed to knowledge, but the distinction seems in different 
 passages lo take these three shapes. See too Cognition. 
 
 Cause, Causality, Cause and Effect. Hamilton intends to employ 
 these terms in the ordinar}- sense, and to offer explanations of them 
 as so used : and when he explains the cause (or i-ather causes) of a 
 thing as the forms in which it previously existed, he does not mean to 
 employ the word Cause in a new signification, but to give a scieutifio 
 
GLOSSARY OF PHILOSOPHICAL TERMS. 171 
 
 explanation of its ordinary use. Apart from his peculiar theory of 
 causation, cause is with him a name fur anything without which the 
 effect would not take place. 
 
 Cognition. This term Hamilton often employs as the equivalent of 
 Knowledge, using the words cognise for know, and cognisable (Mr. 
 Mill writes this word cognoscihh) for that which can be known. 
 When dividing all mental states, however, into Cognitions, Peelings, 
 and Conations, Hamilton uses the word Cognition in its widest sense, 
 to include all the products of intuition and thought — of the senses 
 and the intellect — thus including both Knowledge proper and Belief. 
 In fact belief is not often opposed to cognition, though it frequently is 
 to hnoiohdge. 
 
 Common Sense. This phrase, which belongs to Eeid rather than to 
 Hamilton, embraces the primary, original, or ultimate facts of con- 
 sciousness, on which all the others depend. 
 
 CoMPAEisoN. See Elaborative (Faculty). 
 
 CoMPEEHENSioN and Connotation. When we form a concept (see 
 Conception) the parts of the object or objects on which attention is 
 converged are called the Comprehension of the concept. This com- 
 prehension is merely another name for the concept itself. When we 
 say that the comprehension of the concept Man consists of 
 the two elements Rational and Animal, we mean no more 
 than that the concept itself consists of these two elements. Bat 
 in speaking of the comprehension of a concept we generally 
 imply that the concept is a complex one which may be resolved 
 into parts, which these parts constitute its comprehension ; 
 as will be seen in the above instance. Instead of comprehension, 
 Hamilton sometimes uses the words intension or depth, as opposed to 
 extension or breadth, which latter terms apply to the number of 
 individuals which correspond to the concept. When a term stands 
 for a concept (or for the collection of things corresponding to a 
 concept) Mr. Mill calls the comprehension of the concept, the con- 
 notation of the terra, and the extension of the concept, the c/eHoto^ion 
 of the term. Connotation is thus related to comprehension in the 
 same way that a proposition is related to a judgment — the latter term 
 in each instance referring to the thought in the mind, and the former 
 to its expression in language. Hamilton does not employ the' terms 
 connote or connotation, and therefore probably does not intend to use 
 the tei-ms denote or denotation, in the limited sense of Mr. Mill. 
 
 Conation. Hamilton uses this word as a general term to include both 
 Desire and Will (or VolitionJ. 
 
1/2 GLOSSARY OF PHILOSOPHICAL TERMS. 
 
 Conception, Concept, &c. The word Conception standing both for a 
 mental operation and its product, Hamilton proposes to use the word 
 Concept for the latter, thus confining Conception to the operation 
 alone. The word Conception, however, is often used not only for the 
 act of/crmijzy a concept but for the act of individualizing it, or calling 
 up in imagination an object which exemplifies it. This seems to be 
 in fact the ordinary application of the verb to conceive as well as of the 
 adjectives conceivable and inconceivable. A concept or notion arises 
 from considering or attending to some parts of an object, or of 
 several resembling objects, to the exclusion of the remaining parts, 
 especially if these parts are subjective parts rather than integrant ' 
 parts (see Abstraction). When we consider separately the (subjec- 
 tive) parts in which two or more objects resemble each other, to the 
 exclusion of those in which they differ, we form a general concept, 
 general notion, or general idea, which includes the points of agree- 
 ment to the exclusion of the points of difference. Thus in forming 
 the general concept of a square, I take several square objects and 
 withdrawing my attention from the materials of which they are 
 composed, the positions which they occupy, and even their magni- 
 tudes, and attending only to their figure, I form a notion of that in 
 which alone they agree, and am thusenabled to regard any of them (or 
 any similar figure that I may meet with thereafter) as a square. But 
 it is impossible to realize this concept or notion of a square without 
 having some square object (or objects) present either to the senses or 
 to the imagination. A concept is often described as a collection of 
 attributes, but it may consist (as in this example) of a single attribute. 
 Sir William Hamilton believes that we can form concepts without the 
 aid of language. He appears, however, to have sometimes used the 
 words concept and notion in a wider and vaguer signification, as 
 noticed in the text. Concepts are divided on several principles ; for 
 instance, into Identical or Cognate, and Different ; but Hamilton 
 thinks the most important division is into Congruent or Agreeing, 
 viz., those which can he united in thought, and Confiictive, viz., 
 those which cannot, on which division his theory of judgments is 
 based. It will be seen that these are rather divisions of pairs of 
 concepts than of concepts taken singly. The dispute between the Con- 
 ceptualists and Nominalists has been dealt with in the text. Some 
 philosophers seem to have denied the existence of concepts altogether, 
 and to have described all who believed in their existence as Con- 
 ceptualists. According to them nothing exists, either in the mind or 
 out of it, except individual objects and names. These philosophers 
 
GLOSSARY OF PHILOSOPHICAL TERMS. 173 
 
 were sometimes called Nominalists, and sometimes Ultra-Nomi- 
 nalists. Names were, according to them, transferred from one object to 
 another under the influence of the principle of association when the 
 objects in question resembled each other, and thus what was origi- 
 nally a proper name came to denote, not one, but several individuals 
 which resembled each other : and a name which had been thus trans- 
 ferred was called a general name. They do not seem to have 
 regarded it as having any connotation, the only property which dis- 
 tinguished it from a proper name being according to them that it 
 denoted several resembling intuitions. Hamilton on the other 
 hand appears to regard even proper names as standing for concepts 
 not intuitions. His doctrine is therefore the extreme opposite to 
 that of these Ultra-Nominalists. 
 
 CoKDiTiON, Conditioned, &c. These terms though frequently used by 
 Hamilton are not very carefully defined. Condition appears to be 
 nearly equivalent to both mode and relation, mode being again con- 
 vertible with quality, property, or attribute. The law of the Con- 
 ditioned, as enounced by Hamilton, afBrms that all positive thought 
 lies between two inconceivable extremes, of which, since they are 
 mutually contrudictoiy, one must be true and the other false, though 
 we cannot determine which. One of these extremes always belongs to 
 what be terms the Absolute (see Absolute), and the other to what 
 he terms the Infinite (see Infinite). 
 
 CONGEUENT, CoNFLiCTivE, CoGNATB. See Conception. 
 
 CoNSEETATiVE. The Conservative Faculty, according to Hamilton, is 
 the Memory in the strict signification of that term — the faculty 
 which preserves ideas or other mental states, and renders them 
 capable of being recalled to consciousness, though it requins a, 
 diiferent faculty — the Reproductive — to recall them. 
 
 Consciousness. A general designation for all the mental states thatwe 
 can become cognisant of, when considered in relation to the mind 
 that knows them. It includes the three sub-classes. Cognitions 
 Feelings, and Conations. When we are aware of the presence of any 
 state of mind, we are said to be conscious of it. But Hamilton 
 extends the meaning of the term consciousness to include everything 
 that we know with the same directness and immediateness as our 
 mental states ; and as he believes that certain states of matter are per- 
 ceived as directly and immediately as our pleasures and pains, he 
 maintains that we are conscious of these states of matter as well as of 
 states of mind. 
 
 CONTEADICTION. The law of Contradiction is that no subject (or thing) 
 
174 GLOSSARY OF PHILOSOPHICAL TERMS. 
 
 can have contradictoiy predicates, or more accurately, that the predi- 
 cate cannot contradict the subject. Symbolically it may be ex- 
 pressed. No B is non-B. But Hamilton sometimes uses the expres- 
 sion to include the two co-ordinate laws of Identity and Excluded 
 Middle, the former of which is expressed Every B is B, and the 
 latter Whatever is not B is non-B. He also calls it the law of Non- 
 contradiction, because (considered as a precept) it prohibits contradic- 
 tion, and informs us that a self-contradictory thought is illegitimate. 
 
 CoNVEESiON. The logical process by which, from a given proposition or 
 judgment, we deduce another having the same terms, but in a trans- 
 posed order, as when from B is C we infer that C is B. This con- 
 version is called simple conversion %vhen the quantities of both terms 
 are unaltered after transposition, as when in Hamilton's system from 
 All B is some C we infer that Some C is all B (Some is B or Some 
 C is some B would not be the simple converse of All B is Some C, 
 but what logicians called its converse per accidens). When a propo- 
 sition admits of being simply converted, the original proposition will 
 always reappear on a second simple conversion. By reducing all 
 propositions to equations and inequalities, Hamilton rendered them all 
 simply convertible. 
 
 CosMOTHETic (IDEALISM). Cosmothetic Idealism, or Hypothetical 
 Realism, is the theory which admits the existence of matter (or of the 
 external world) hut denies the immediate perception of it. As on 
 this theory we do not immediately perceive the external world, the 
 question arises. What is it that we do perceive.'' And hence arise 
 three sub-divisions of Cosmothetic Idealists, viz. : 1. Those who 
 maintain that what we perceive is not a, modification of our minds 
 but of something else; 2. Those who hold that it is a modification 
 of our minds, but one which continues to exist when we cease to be 
 conscious of it; and 3. Those who hold that it is a mere state of con- 
 sciousness whose essence consists in being felt. Hamilton sometimes 
 classes the second and third of these sub-divisions together, thus 
 dividing the class into two sub-classes instead of three. The doctrine of 
 Cosmothetic Idealism is what Hamilton specially refers to as the Ideal 
 theory, the representative theory of perception, or the representative 
 hypothesis ; and one main object of his reasonings concerning the 
 external world is to show that the Cosmothetic Idealist has no right 
 to believe in its existence, and only attains it by means of a para- 
 logrom. 
 
 Denote, Denotation. See Conception and Connotation. 
 
 Dictum. Aristotle's Dictum, on which he founded the theory of the 
 
GLOSSARY OF PHILOSOPHICAL TERMS. 175 
 
 SjUogism, is that whatever is afifirmed or denied of a lohole class 
 may be aflSrmed or denied of anything contained in the class. This 
 is known as the Dictum de omni et de nulla. 
 
 Ego, Non-ego. Hamilton uses the Latin ego in preference to the 
 English I or myself, because the former is not liable to be con- 
 founded (in oral delivery) with the eye, and can be used either in 
 the nominative or the objective case. The non-ego, of course, means 
 anything that is not the ego, and would therefore include any other 
 mind than my own ; but with Ha.nilton the non-ego is often used 
 as the equivalent oi matter. 
 
 Elaboeative (Faculty). The Elaborative Faculty is Hamilton's desig- 
 nation for the faculty of thought or comparison, also known as the 
 discursive faculty. This is the faculty which gives rise to concepts 
 (hence abstraction is one of its operations), judgments, and reasonings, 
 all of which are so many modes of comparison. Logic is the science 
 of its operations. Concepts are formed by comparing intuitions, 
 judgments by comparing concepts, and reasonings by comparing 
 judgments Under the head of comparison, Hamilton includes 
 the conditions or pre-requisites of the act of comparison, and also 
 its results. All our perceptions of relations are due to this faculty, 
 every relation being the result of a comparison, and every act of 
 comparison implying the perception of a relation. 
 
 Empiricism. Bmpieical. Eipeeience. Empiricism is the system 
 which explains all the phsenomena of the human mind by means of 
 Experience. But the term Experience itself has been differently 
 understood, standing- sometimes for sensations or other rude materials 
 of knowledge, and sometimes for the knowledge derived from them, 
 and into which they enter : while again, other writers appear to limit 
 its meaning to what has been termed external experience. With 
 these latter philosophers Empiricism becomes Sensualism or Sensa- 
 tionalism. The fundamental principle of Empiricism seems to be 
 that there are no judgments or propositions which are from the first 
 universal and necessary, while it is also maintained that all our 
 earlier judgments or propositions are singular — relating to individual 
 objects only — and that the great instrument for generalizing these is 
 induction (see Induction). When Empiricists include mental expe- 
 rience in their sources of knowledge, there is some risk of verbal 
 questions arising between them and philosophers of the school of 
 Hamilton. I make for example a number of unsuccessful efforts to 
 imagine two right lines enclosing a space, and at the end of the 
 process conclude that it is impossible for them to do so. One 
 
176 GLOSSARY OF PHILOSOPHICAL TERMS. 
 
 philosopher says that this is the result of an universal and necessary- 
 law of mind. Another says that it is a generalization of my mental 
 experience on the subject. The.se statements seem to be two ways of 
 expressing the same fact, provided that the mental experience is 
 admitted to be original, and not dependent on association of ideas or 
 acquired knowledge and habits of thought. The word Empirical is 
 sometimes used by Kant, not for that which is derived from experience, 
 but for that which is applicable to (or involved in) experience, though, 
 perhaps, itself a joHorj. This employment of the term does not, I 
 believe, occur to Hamilton. 
 
 Eneebt. This word in Hamilton is nearly equivalent to action. 
 
 Ens. a wide term for anything that exists, and hence nearly equivalent 
 to existence. Thus Hamilton in one place says that ens is the 
 primum cognitum, or fir.st thing known, which he elsewhere says 
 of existence, since all thought and all knowledge implies the know- 
 ledge, or thought, of existence. 
 
 Excluded (Middle). The law of Excluded Middle is, that whatever 
 is not B is non-B, where B is any concept whatever. The meaning 
 of the phrase Excluded Middle is, that any third, or intermediate, 
 alternative is excluded or inadmissible. If the thing is not B, it 
 is non-B. There is no possibility of its being neither. It likewise 
 cannot be hotli; but this results, not from the law of Excluded 
 Middle, but from that of Contradiction. No B is non-B, implies 
 that nothing is both B and non-B. Hamilton describes the law 
 of Excluded Middle as the principle of disjunctive judgments; but 
 if the proposition Everything is either B or non-B, implies that 
 nothing is hoth B and non-B, the principle of Contradiction, is 
 involved in it as well as that of Excluded Middle. Hamilton, how- 
 ever, regards the two principles as different phases of the same law. 
 See Contradiction. 
 
 ExisTEKCE. In some passages Hamilton seems to identity existence 
 with substance, at least when he speaks of absolute existence, 
 existence in itself, Ac. Attributes, qualities, phfenomena, &c., 
 which alone are known to us, are thus characterised as modes, or 
 forms of existence. That we cannot conceive existence as absolutely 
 commencing or terminating, is nearly equivalent to saying that we 
 cannot conceive substance as beginning or ceasing to exist ; and thus 
 the permanence (both anterior and posterior) of substance, or rather of 
 substances, lies at the basis of his assertion that we cannot regard 
 the quantity of existence as either increased or diminished. See 
 Substance. 
 
GLOSSARY OF PHILOSOPHICAL TERMS. 177 
 
 Extension, Extensive. According to Hamilton we perceive or cognise 
 what is usually called space or extension, both d priori and a pos- 
 teriori, and he proposes to distinguish them by calling the a priori 
 idea, space, and the a posteriori idea, extension. We have also to 
 consider the extension of a concept or a name. This is merely the 
 number of individual objects which correspond to the concept, or to 
 whom the name is applicable. Hamilton often speaks as if this 
 extension was essential to the concept, and might be discovered by 
 mere analysis of, or reflection on, the concept as it exists in the mind ; 
 but it can hardly be said that he includes the property of having an 
 extension in the meaning of the word concept, or that he would 
 withhold the term concept from our ideas of a dragon or a griffin, 
 which have no (real) extension. See Conception, Comprehension, and 
 Ampliative. The extension of a term is sometimes called its deno- 
 tation. The extensive quantity of a thing or collection of things, 
 is its magnitude measured by bulk or number, and is thus distin- 
 guished from intensive quantity or degjree, and from protensive 
 quantity or duration. 
 
 Faculty. A faculty, according to Hamilton, is not any thing in the 
 mind, or any separable portion of the mind, but is a general name 
 for the mind when acting in a particular way. Similar mental 
 acts are referred to the same faculty ; dissimilar acts to different 
 faculties. His enumeration of faculties are — the Perceptive (which 
 has two branches. External and Internal), the Conservative, the 
 Reproductive, the Representative, the Elaborative, and the Regu- 
 lative. These, however, are properly the Cognitive Faculties, and 
 do not include the Emotions and the Will (Feeling and Conation). 
 Consciousness is not a faculty, but includes all the faculties. They 
 all operate only in so far as we are conscious of them. 
 
 Feeling. Hamilton uses this word to denote those states of mind 
 which are pleasurable or painful, and mainly consist in pleasure and 
 pain. Feeling is purely subjective, in contrast with cognition or 
 knowledge, which is objective. But here we must recollect the dis- 
 tinction which Hamilton draws between the subjectivo-object and 
 the objectivo-object. Feeling is subjectivo-subjective. There is no 
 object of any kind in pure feeling ; while in cognition, though some- 
 times there is no objectivo-object, there, is at least a subjectivo- 
 object. Knowledge and feeling, however, always co-exist, (though 
 the one rises higher as the other sinks lower,) and in actual ex- 
 perience we never meet with a state of pure feeling without know- 
 ledge, or of pure knowledge without feeling. Feelings are subdivided 
 into Sentiments and Sensations. 
 
178 GLOSSARY OF PHILOSOPHICAL TERMS. 
 
 FiGUEE. The figure of a Syllogism is determined by the arrangement 
 of the Micdle Term as predicate or subject in its premisses. Thus if 
 the Middle Term is the subject of the major premiss, and the predicate 
 of the minor premiss the Syllogism is said to be in the first figure- 
 See Major. 
 
 FoBCE. 'J his word with Sir W. Hamilton implies not merely something 
 that accelerates or retards motion (whether of our own bodies or of 
 extra-organic matter), but a certain nisus or effort of which we are 
 conscious. The same observation applies to Sesistance. An in- 
 terplanetary medium which slightly retarded the motions of the 
 earth and planets, would not be regarded as offering resistance if it 
 produced no conscious effect on our muscular system. Resistance is, 
 in fact, conscious resistance to our locomotive volition, and to our 
 organism when in nio'"ion under the influence of that volition. This 
 employment of the terms force and resistance is not peculiar to 
 Hamilton, but it may be worth while to point out that their use in 
 Physics and Psychology do not alwaj-s correspond. Hamilton also 
 occasionally employs the term. Jbrce for a positive principle or positive 
 necessity in contrast to an impotence or imhecility. 
 
 Poem. Hamilton uses this word in the Kantian sense, for an universal 
 and necessary element in certain facts of consciousness without 
 which the others could not exist. Thus space in the Kantian system 
 is the form of external sensation, and time is the form of sensation, 
 both external and internal, because without space the external sensa- 
 tion would sink into an internal sensation, and without time the latter 
 would disappear also. But Hamilton is less careful than Kant as 
 to the terms which he employs in connexion with the word /orm, 
 and seems hardly to distinguish between Forms of sense. Forms of 
 imagination, and Forms of thought. In fact, he describes space in 
 each of these tbx-ee ways in different passages of his writings. The 
 Forms of all the faculties being universal and necessary, are referred 
 by him to the intellect, or regulative facult}-. In Logic the use of 
 the word Form is, in some cases at least, different. Thus, when we 
 speak of the Forms of Propositions, we do not mean the universal and 
 necessarj- part of propositions, but the heads or classes under which 
 propositions may be arranged. The former use of the word Form is 
 borrowed from Aristotle, with whom Matter meant everything that 
 is not Form; but Hamilton usually employs matter and its correla- 
 tives only for that which occupies space, and constitutes the external 
 world. When Hamilton describes the cause of a thing as the form 
 (or forms) in which it previously existed, he employs the word nearly 
 in the same meaning as state or mode. 
 
GLOSSARY OF PHILOSOPHICAL TERMS. 179 
 
 Geneealization, General Notions. See Abstraction, Conception. 
 
 Idea. This word rarel}' occurs in Hamilton's writings, and then usually 
 ia a very wide sense, including intuitions, representations, concepts, 
 and almost CTery other state of consciousness, as in the phrase 
 Association of Ideas. 
 
 Idealism. The doctrine which denies the existence of the external 
 world or matter, and maintains that nothing exists, or is known, 
 except minds. This doctrine Hamilton sometimes designates Abso- 
 lute Idealism, giving the name of Cosmothetic Idealism to the 
 doctrine which denies the immediate knowledge of the external 
 world, but holds that it exists, and can be mediately known or in- 
 ferred. See Cosmothetic (Idealism). 
 
 Ideal Theoet. The theory which maintains that we do not perceive 
 external or material objects themselves, but only certain ideas of 
 them. The word idea is here used in a narrower sense than by 
 Hamilton. 
 
 Identity. The law of Identity affirms the complete identity between 
 a concept and its entire comprehension, and the partial identity 
 between it and any part of its comprehension. The symbolical ex- 
 pression of this law is B =: B. This law, together with those of 
 Contradiction and Excluded Middle, constitute the fundamental 
 laws, or rather law, of Logic ; for Hamilton, as already stated, regards 
 them as three phases of the same law. Personal identity, Hamilton 
 thinks, is first perceived when we compare a past state of conscious- 
 ness, represented in the memory, with a present state; and it is in 
 this perception of personal identity that we first recognize the ego or 
 self As to Absolute Identity, see Absolute. 
 
 Imagination. Hamilton calls this faculty the Representative Faculty, 
 and its products are what are properly termed representations — a 
 word which some philosophers use as widely as idea. The Eepre- 
 sentative Faculty is more strictly what is called the Reproductive 
 Imagination, what is known as the Productive or Creative Imagina- 
 tion involving (according to Hamilton) the operations both of the 
 Representative and of the Elaborative Faculties. Re-presenta- 
 tion is opposed by Hamilton to presentation, the thing being 
 presented when it first enters the mind (by means of the senses), 
 and re-presented when it is afterwards called up by the imagination. 
 The imagination, he believes, employs the same sensitive organ in 
 representing that was originally employed in presenting, the difi'er- 
 ence being that in one case it is excited by external, and in the other 
 by internal, iufluences. Mr. Mill (following Hume), often uses idea 
 in the sense of Hamilton's repreientation. Representations must, 
 N 2 
 
i8o GLOSSARY OF PHILOSOPHICAL TERMS. 
 
 in Hamilton's system, be distinguished both from intuitions and 
 concepts. See the next head. 
 
 Immediate oe Intuitive (Knowledge). Immediate or intuitive know- 
 ledge or cognition is distinguished by Hamilton from mediate or 
 representative knowledge or cognition. Here the word represen- 
 tative is used in a wider sense than in connexion with the imagination 
 (just considered) since, whenever we do not know or perceive the thing 
 itself (whether a state of mind or of matter), but only something else 
 from which it can be inferred or deduced, our knowledge is said to be 
 representative. Thus I have only a representative knowledge of a 
 distant object (so long as it continues at a distance), though, what I 
 immediately know when contemplating it, may be a state of matter 
 rather than of mind. Using the word object so as to include our 
 states of mind, as well as the states of the material world, the great 
 distinction between these two kinds of knowledge is, that in intuitive 
 or immediate knowledge, there is but a single object which is directly 
 cognized, whereas in representative or mediate knowledge there 
 are two objects, one of which is directly cognized, while the other 
 is cognized only indirectly, and through it. There seems to be a 
 corresponding distinction between immediate and mediate belief; 
 indeed Hamilton often uses the word cognition, to include both 
 knowledge and belief. 
 
 Incompeessibieity (UtTiMATE). The Law of Ultimate Incompressibility, 
 according to Hamilton, is that law, by which a material object is 
 incapable of extrusion from space, or of being compressed into 
 nothing. It is distinct from Resistance, because it relates only to a 
 compressing (not to a translating) force, and because it alleges that 
 the resistance thus opposed to the compressing force would ulti- 
 mately become insuperable, no matter how the force might be 
 increased. 
 
 Inconceivable. That which cannot he conceived (see Conception, 
 Concept) : but the verb to conceive is used not only in the sense of 
 forming a concept, but also in the sense of picturing in the imagi- 
 nation an object corresponding to the concept when formed. There 
 are therefore at least two kinds of inconceivables, viz., when the 
 proposed concept cannot be formed (being inconsistent with the laws 
 of thought) and when, though it can he formed, no corresponding 
 object can he perceived or imagined. Thus that which is neither 
 white nor non-white is an inconceivable of the former kind, while a 
 space enclosed by two right lines is an instance of the latter. Ha- 
 milton again derives the latter kind of inconceivableness from two 
 sources, a positive and a negative one ; for I may fail to imagine an 
 
GLOSSARY OF PHILOSOPHICAL TERMS. i8i 
 
 object corresponding to a concept (or to a combination of two concepts) 
 because some law of my nature forces me to imagine the opposite, or 
 because owing to the limitations of my faculties I cannot ima.ijine 
 either of two things one or other of which must be real (see Con- 
 ditioned). Mr. Mill charges Hamilton with using the term Incon- 
 ceivable in other senses, but I think unjustly. Whatever is conceived 
 must of course come under a concept as well as be present to the njind 
 in an intuition or representation (as already explained). Both 
 imagination and thought are thus requisite to the act of conception. 
 
 Induction. The mental operation by which from a number of individual 
 instances, we arrive at a general law. The process, according to Hamil- 
 ton, is only logically valid when all the instances included in the law 
 are enumerated. This being seldom, if ever, possible, the conclusion 
 of an Induction is usually liable to more or less uncertainty, and 
 Induction is therefore incapable of giving us necessary (general) 
 truths. 
 
 Infinite. The unlimited : meaning in its strict sense that which is 
 unconditionally unlimited, or, in all respects and relations, unlimited. 
 Negative attributes being limitations, no negative attribute can belong 
 to the Infinite. In a looser sense the word is used for that which is 
 greater than any finite. The Infinite and the Absolute are with 
 Hamilton two subdivisions of the Unconditioned. See Absolute. 
 
 Intellect, Intelligence. These words do not occur in Hamilton's 
 list of Faculties, but his use of them seems to correspond very nearly 
 with the Regulative Faculty, with the occasional addition of the Ela- 
 borative Faculty : which see. 
 
 Intension. See Comprehension. Intensive quantity (as opposed to 
 extensive quantity) is a phrase which Hamilton often employs in the 
 sense of degree and especially degree of vividness. 
 
 Inteenal. Internal sense, or Internal perception, is the faculty which 
 perceives or apprehends the states of our own minds, such as pleasure 
 and pain, in contrast to the states of the external world. The faculty 
 of Perception includes the two subdivisions External Perception and 
 Internal Perception. 
 
 Intuition. Intuition or Presentation is opposed to thought and its 
 various products (see Elahorative Faculty), and embraces the 
 products of the Faculty of Perception, whether External or Internal. 
 It is an immediate knowledge or cognition of something in space, 
 in time, or in both. Its object is sometimes said to be individual, 
 which is so far true that the object of an intuition can never be 
 general ; but on the one hand an intuition, such as that of the table 
 before me, often consists of many separable parts, and on the other 
 
1 82 GLOSSARY OF PHILOSOPHICAL TERMS. 
 
 hand, in order to recognize an individual obj(?ct as the same that we 
 previously knew, we must have at least two intuitions (a present and 
 a past one) and institute a comparison between them. Occupation of 
 a definite portion of space, or time, or b.th, seems to be the most 
 definite characteristic of an intuition, while a concept is something that 
 (usually atleast) equally belongs to more than one intuition, each of these 
 intuitions having its own position in space and time. Hamilton, how- 
 ever, distinguishes an intuition or presentation from a representation 
 as well as from a concept. {See Imagination and Conception.) 
 
 Judgment. In one meaning of the word, any apprehended relation 
 between two states of consciousness is a judgment ; but as the appre- 
 hension of a discrimination and relation between two such states is 
 essential to all consciousness, every act of consciousness thus implies 
 a judgment. In its narrower meaning, a judgment is a relation 
 between two concepts which form its subject and predicate. In this 
 sense it is the second operation of the Elaborative Faculty with which 
 Logic deals, viz., the mental process corresponding to a proposition. 
 It is in this latter sense that judgments are divided into Analytical or 
 Explicative and Synthetical or Ampliative, as already mentioned. 
 The two meanings of the vioyA judgment are sometimes distinguished 
 as Psychological judgments and Logical judgments. The best verbal 
 expression for the former kind of judgment, according to Hamilton, is. 
 This is here, or, That is there. 
 
 Knowledge. See Cognition. 
 
 Latent (.VIodifications). A latent state or modification of the mind is 
 one of which we are not conscious at the moment, hut which is never- 
 theless capable of producing effects on consciousness. It would seem 
 to be of two kinds, viz. that which is not at present producing any 
 effect on consciousness, but is capable of producing effects hereafter, 
 (for instance, when recalled to the mind by an act of memorj-), and that 
 which is producing a present effect on consciousness, though it is itself 
 latent. But Hamilton is of opinion that all latent modifications are 
 of this latter kind, every mental activity that we have once experienced 
 continuing to exist in a state of latency (but occasionally rising again 
 into consciousness) during the whole remainder of our lives. 
 
 Law. Hamilton uses this word both for the expression of the universal 
 and necessary facts of consciousness (see Form) and also for the 
 generalized facts of our internal experience. It is used in the latter 
 meaning, for instance, when Hamilton tells us that the laio which 
 connects sensation and perception is that they always co-exist, but are 
 in the inverse ratio of each other : while it is used in the former 
 meaning in such expressions as the ?««' of contradiction. When used 
 
GLOSSARY OF PHILOSOPHICAL TERMS. 183 
 
 so as to impl}' necessity, this necessity may be either of a positiye or 
 a negative character. (See Necessity.) 
 
 Limit. Samilton seems occasionally to employ this verb and its cognates 
 in the sense of to mark out or define; as when, in law, an estate is 
 said to he limited to a man and his heii's, that being in fact what 
 would be popularly called an unlimited estate. 
 
 Locomotive. The Locomotive Faculty does not occur in Hamilton's list 
 of faculties, and is in fact only a name for the power of setting our 
 muscles in motion by means of will or volition. In so doing, Hamil- 
 ton thinks there is a consciousness of effort, distinct both from the 
 volition to move and the sensations which accompany the movement, 
 (these are called muscular sensations, and are usually referred to what 
 is called the Muscular Sense, though sometimes included under the 
 sense of Touch). Volition being always directed to an end, the greater 
 or less amount of effort necessary under different circumstances to 
 accomplish this end, would, apart from any accompanying sensations 
 (according to Hamilton), reveal to us the fact that our locomotive 
 energy was resisted ; and it is by this resistance to our locomotive 
 energy that the existence of an extra-organic world is first revealed 
 to us. This doctrine only appears in Hamilton's Dissertations to 
 Eeid. The volition to move presupposes the notions of space and 
 motion in space, but Hamilton has not directly described the latter 
 of these notions as a priori. 
 
 Logic. With Hamilton, Logic is the science of the formal laws of thought, 
 or the science of the laws of thought as thought. It is thus the 
 science of the laws and products of the Elaborative Faculty : which 
 see. It does not concern itself with any inference or evidence which 
 is not absolutely conclusive. 
 
 Majoe, Minoe, Middle. The words major and minor are applied in 
 Logic to both propositions and terms. In a syllogism the major term 
 is the predicate of the conclusion, the minor term is the subject of 
 the conclusion and the term which occurs in the premisses, but not in 
 the conclusion, is called the middle term. The major premiss is the 
 premiss which contains the major term and the middle term : the 
 minor premiss is that which contains the minor term and the middle 
 term. The word middle is applied only to the term, and not to any 
 proposition. An undistributed middle is the fault which occurs in a 
 syllogism where the middle term is particular (see Particular) in 
 both premisses. Thus in the syllogism 
 
 Some B is (some) C, 
 
 Some C is (some) D, 
 
 Therefore some D is (some) B. 
 
i84 GLOSSARY OF PHILOSOPHICAL TERMS. 
 
 B is the major term, C is the middle term and D is the minor terra ; 
 some B is (some) C is the major premiss : some C is (some) D is 
 the minor premiss : some D is (some) B is the conclusion ; and the 
 syllogism is invalid on account of the fault known as undistrihuted 
 middle, the middle term C being particular in both premisses. 
 
 Matebialism. The theory of perception according to which the perceiver 
 and the perceived are alike material — mind being only a kind of matter 
 or a product of matter. 
 
 Matter. See Form. 
 
 Metaphtsics. This term is employed for both Psychology and Ontology, 
 but is more properly applicable to the latter, according to Hamilton. 
 
 Mode. This word is usually' equivalent to state, and nearlj- coincides in 
 meaning with accident, attribute, quality, &c., as contradistinguished 
 from substance or subject. In Logic it has a different meaning, 
 namely, a particular arrangement of premisses and conclusion ; as the 
 mode UAA signiiips a syllogism in which the major premiss is U, the 
 minor premiss A and the conclusion A (the meanings of which vowels 
 appear by Hamilton's Table of Prepositional Forms). Popularly 
 it IS used as equivalent to way or method ; but not by Hamilton. 
 
 Natueal (Realism or Dualism). Natural Realism or Natural 
 Dualism is Hamilton's name fur the doctrine which maintains that 
 in perception we are conscious at once of mind and of matter — of the 
 ego and of the external world. Sealism, as thus used, implies a 
 belief in the external world, and accordingly the Cosmotbeticldealists 
 are also described as Hypothetical Realists. This vise of the word is 
 quite distinct from that in which Sealism is opposed to Nominalism. 
 Realists, in that sense, were those who believed that there were real 
 things which corresponded to our general ideas or concepts — these 
 real things not being the individual things contained in the exten- 
 sion of the concept, but universals. They seem to have been what 
 Plato called Ideas, so that in this meaning of Realism and the 
 Platonic meaning of Idea, Realism and Idealism would coincide 
 instead of being opposed. The old use of the word Realism only 
 occurs in a few historical passages in Hamilton. It is not, of course, 
 to be identified with Dualism. 
 
 Necessity. Besides the use of this term to imply what we cannot avoid 
 thinking or judging, the word Necessity is often applied to the 
 doctrine which denies the freedom of the human will, and even to that 
 form of the doctrine which confines itself to asserting that volitions 
 have invariable antecedents which would enable any person who 
 knew all the antecedents to predict the volitions with perfect accuracy. 
 Hamilton's divisions of Necessity are given in the text. That to 
 
GLOSSARY OF PHILOSOPHICAL TERMS. 185 
 
 which he attaches most importance is the division into positive and 
 
 negative necessity. Necessitj' is his great test for distinguishing 
 
 the original furniture of the mind from the subsequent acquisitions 
 
 of experience. 
 
 Negative. Every concept has its ntgative, the one being e.tpressed as 
 
 B, the other as rion-B. The same observation is true of everj- attribute 
 
 or name. But concepts and attributes are often described as negative 
 
 when they are such as we cannot conceive either at all or in the 
 
 required combination. Negative in this latter sense is equivalent to 
 
 inconceivable, and positive to conceivable. Passing on to judgments 
 
 or propositions, a negative judgment strictly speaking is tliat whose 
 
 copula is »« not instead of is, as Man is not a quadruped. But a law 
 
 or principle is sometimes described as negative, not because it is 
 
 expressed by a negative judgment or proposition, but hecause its 
 
 necessity is of a negative kind as already explained. These various 
 
 meanings or applications of the term negative often require to be 
 
 borne in mind. The principle of Contradiction — No B is non-B — is 
 
 expressed by a negative judgment, but it possesses the highest kind 
 
 of positive necessity: and instances of the opposite kind could easily 
 
 be given. 
 
 Nihilism. The doctrine which recognizes nothing but passing mental 
 
 modifications, and denies the independent existence of mind and 
 
 matter as well as of any higher substance. 
 
 Nominalism. See Conception, Concept. 
 
 NoMOLOGT. The Science of Laws as opposed to phasnomena. Thus, 
 
 Logic is the Nomology of the Elaborative Faculty. 
 Non-ego. See Ego. 
 
 Notion. Usually employed by Hamilton in the same meaning as con- 
 cept, but he sometimes uses it in a wider signification. A combina- 
 tion of attributes (whether positive or negative) which violates the 
 laws of thought (or any other necessary mental law) may be called a 
 notion, but not a concept. Thus we may speak of the notion, hut not 
 the concept, of a square-circle. 
 Object, Objective. Anything which can be separately considered and 
 regarded apart from the conscious mind is in Hamilton's language 
 an object. It may be only a state of the mind, in wliich case it is 
 called a subject-object or subjectivo-object, or it may be a state of 
 matter or of the external world, in which case it may be called an 
 object-object or objectivo-object. In the case of subject-objects, there 
 is no real distinction between the mental act or operation and its 
 object, the act of imagining a centaur being, in fact, the same thing 
 with the representation (or imagination) of a centaur ; but in the 
 
i86 GLOSSARY OF PHILOSOPHICAL TERMS. 
 
 case of an objeut-objeet, the operation and the object are quite distinct, 
 the one being mental and the other material. In immediate know- 
 ledge there is only one object, which may be either a subject-object 
 or an object-object ; hut in mediate knowledge there are two objects, 
 an immediate object which is always a subject-object and a mediate 
 object which is usually an object-object. Thus when I imagine 
 London Bridge in its absence, the immediate object of the act of 
 imagination is my present mental representation of the bridge, and 
 the mediate object is the bridge itself as I formerly saw it. There is 
 another use of the term, however, owing to which 'Hamilton's lan- 
 guage is sometimes ambiguous. The object oi a mental act or state 
 sometimes means not that which is cognized in the act or state, 
 but that which causes or producci the cognition ; and thus understood 
 the immediate object means that which immediately causes or pro- 
 duces the mental state, while the mediate or remote object means 
 that which ultimately causes or produces it, by affecting the imme- 
 diate cause. In this way the vibrations of the air in contact with 
 the ear may be said to be the immediate object of the sense of hear- 
 ing, even by those who maintain that we are not immediately cog- 
 nizant (or conscious) of these vibrations; while the mediate or remote 
 object would be the sounding body at a distance which sets the air in 
 vibration, and thus causes the immediate cause of the sensations of 
 sound, of which latter alone I am on this theory conscious. It is not 
 easy to determine whether in some passages Hamilton intends using- 
 the yi\iva.se immediate object in this latter sense or in the sense of that 
 which is immediately cognized, and some obscurity is thus thrown over 
 his Natural Realism. The word objective is free from this ambiguity ; 
 but it may mean either subjectivo-objective or objectivo-objectivet 
 the former meaning being more common with the earlier English 
 writers, and the latter meaning with the later. Reid used the word 
 object in the sense of objectivo-object exclusively (I believe) and Mill 
 seems to understand it in the same sense whenever it occurs in the 
 pages of Hamilton. 
 Ontoloot. The science of being as being, as distinct from the knowledge 
 of any of its phiEuomenal manifestations. Thus a science of the 
 Absolute or of the Infinite would be an Ontology. Such sciences 
 Hamilton thinks impossible, yet as he gives Ontology, or Inferential 
 Psychology, a place in his division of Philosophy, it may be assumed 
 that he believed that in some instances we could proceed beyond the 
 facts of consciousness by waj' of legitimate inference. Natural 
 Theology would probably come under this head. With the earlier 
 philosophers Ontology usually included Rational Psychology or 
 
GLOSSARY OF PHILOSOPHICAL TERMS. 187 
 
 Pneumatology, Rational Cosmology and Rational Theology, the word 
 Rational being used to indicate that all these sciences were based on 
 grounds independent of experience. 
 
 Opeeation . This term, like the words act and energy, seems to be often 
 used by Hamilton to include mixed states of action and passion. 
 (We are never, he thinks, conscious of pure passivity.) Thus he 
 speaks of perception as an operation; though the mind is, for the most 
 part, passive in perception. 
 
 Okgan, Obganism. These words seem to be sometimes used for the 
 whole of the human body, while at other times they are limited to 
 the nervous system. 
 
 Paecimont. The law which forbids us to assume more causes or 
 principles than are necessary to account for the facts to be explained 
 is termed by Sir W. Hamilton the law of ■parcimony. It not only 
 forbids us to assume more causes than are necessary, but also to assume 
 more onerous causes than- are required. This latter phrase appears 
 to mean that we must not assume a positive force or power to explain 
 what can be accounted for by a mere negative inability. He adds 
 two laws, described as the laws of Integrity and Harmony, which, 
 however, seem less important. 
 
 Paexiculae. Hamilton uses this word in the meaning of some, but 
 generally more than one. His use is not to be confounded with that 
 of many recent writers, like Mr. Mill, who use particular in the 
 sense of individual (whence, I suppose, an individual is now some- 
 times called a ^arf^). K particular proposition,-vii\l[i'i{diia\\tor\,'w 
 one of the form Some Bs are Cs, not of the form This B is C — which 
 would be a singular proposition. Hamilton uses tlie word soine, 
 however, in the sense of some only. 
 
 Peeception. In its wider sense, perception is nearly equivalent to 
 ^ intuition or presentation. The faculty of perception is that by which 
 ideas first enter the mind, and it has two branches. External Percep- 
 tion and Internal Perception — the former again including the five 
 senses. In a narrower K-nse perception is opposed to sensation, and 
 is limited to the objective (as sensation is to the subjective) character- 
 istics of the products of the faculty of perception. In this sense it 
 seems to be exclusively applied to external perception, and what 
 Hamilton speaks of as the various theories of perception are in fact 
 theories of external perception only. The characteristic property of 
 perception, in this narrower sense, is the reference to space — at least in 
 the form of localitj'. The primary qualities of matter belong to per- 
 ception, and the secondary to sensation (the secundo-primary being 
 attained by the locomotive faculty). In popular language we often 
 
i88 GLOSSARY OF PHILOSOPHICAL TERMS. 
 
 speak oi perceiving a relation between two things, or perceiving the 
 truth of a proposition, and by some writers perception is used in as 
 wide and vague a sense as idea. The reader must bear in mind that 
 Hamilton never adopts these latter meanings of the term. The word 
 percept seldom if ever occurs in Hamilton. Had he employed it 
 (like concept) he would have avoided some of the ambiguities attach- 
 ing to the phrase object of perception. 
 
 PnaiNOMENON. Or appearance. Used by Hamilton for a mode, state, 
 quality, attribute, accident, or property, either of mind or of matter. 
 Kant uses the term in contrast to noumenon — the thing as it really 
 is ; whereas phenomenon with him means the thing as it appears 
 to us. The word noumenon is not employed by Hamilton ; and he 
 opposes the tevm phcenomenon not to noumenon, but to substance: 
 e. g. he describes the principle of Substance as the law of substance 
 and phsenomenon. 
 
 Philosophy. Hamilton uses this word as nearly identical with what is 
 often called Mental Philosophy. See Metaphysics. 
 
 PosTRElOEi. See Priori. 
 
 Potential, Potentiality. That which is capable of becoming some- 
 thing else, is sometimes said to be potentially that something else. 
 Thus if B may become C, it is said to be potentially C. But this 
 potentiality is two-fold, for the thing may be capable of being changed 
 into C by the operation of something else (which we may call D), or 
 it may be capable of changing itself (unaided) into C. In the former 
 case, however, the proper expression would seem to be that B and D 
 together are potentially C ; and this, I think, is the way in which 
 Hamilton uses the word potential, and its cognates. 
 
 Peedicate. Every judgment or proposition contains the two elements, 
 viz. something about which an assertion is made and something that 
 is asserted of it. That about which the assertion is made is called 
 the subject (it might perhaps have been better designated the object), 
 and that which is asserted of it, is the predicate. Thus in the pro- 
 position Every man is mortal, man (or every man) is the subject of 
 the proposition, and mortal is the predicate. The word is (or is 7iot) 
 which connects them is known as the copula. A proposition thus 
 consists of a subject, a predicate, and a copula, as does also a judgment. 
 (I have, however, here assumed the proposition to be what is called a 
 categorical proposition. See Proposition) 
 
 Peemiss, OE Peemise. a judgment or proposition when employed in a 
 Syllogism — every syllogism consisting of two premisses and a con- 
 clusion. These premisses are called the major premiss and the minoi 
 premiss, as already mentioned. 
 
GLOSSARY OF PHILOSOPHICAL TERMS. 189 
 
 Pbesentatiok", Pkesentative. Presentation is nearly equivalent to 
 intuition and perception, which see. Intuitive or immediate know- 
 ledge is also described as presentative knowledge. We are not 
 therefore, however, to conclude that all presentative knowledge con- 
 sists of presentations. That which is immediately known must, accord- 
 ing to Hamilton, Represent to the mind, both in time and (if it be a 
 material object) in space. Hence probably the derivation of the term 
 presentation. 
 
 Peimaet (Quality). Hamilton divides the qualities of matter, as known 
 to us, into primar}', secundo-primary, and secondary. The primary 
 are all resolvable into, and deducible from, the fundamental element, 
 occupation of space ; and space being a priori as well as empirical, 
 they are to a great extent a priori, and dependent on the intellect 
 alone. We perceive them in our organism. The secundo-primary 
 qualities are all reducible to resistance to our locomotive volition, and 
 are perceived by means of the locomotive faculty. They alone are 
 immediately perceived, according to Hamilton, in extra-organic bodies. 
 The secondary qualities, like the primary, ai"e affections of our organism, 
 but when taken alone do not include any direct reference to space, and 
 are perceived in the organism rather as a sensitive or animated, than 
 as an extended or material, organism. 
 
 Peinciple. This word is nearly identical with law. But an ultimate 
 principle seems to be occasionally used for an ultimate being. 
 
 (A) Peioei. a general name for that which is derived from the nature of 
 the mind itself independently of experience; in contrast to a ^osie- 
 riori, or empirical, meaning that which comes from experience. 
 
 Peoposition. The expression, in words, of a judgment. Propositions 
 are divided on various principles ; into affirmative and negative : into 
 categorical, hypothetical, and disjunctive (the categorical is of the 
 form B is C, the hypothetical of the form. If B is C then D is F, and 
 the disjunctive is of the form Either B is C or D is F ; but Hamilton 
 seems to limit it to the form, B is either C or D) : into universal, par- 
 ticular, and singular, &c. This latter division being based entirely 
 on the quantity of the subject, is superseded by Hamilton's quan- 
 tification of the predicate, and appears in a different shape in his 
 system. His list of Propositional Forms is given in the text. 
 
 PsTCHOLOGT. The Science of Mind. 
 
 Quantification. Expressing in words the quantity of a thing. Thus 
 the quantification of the predicate, means expressing in words the 
 quantity of the predicate. 
 
 QUANTITT. This word seems to be sometimes used for that which possesses 
 quantity {quantum), as well for quantity itself {quantitas). Quantity 
 
I90 GLOSSARY OF PHILOSOPHICAL TERMS. 
 
 is of three kinds, extensive (magnitude or number), protensive (mea- 
 sured by time), and intensive (measured by vividness, or degree of 
 vivacity). 
 
 Eealism. See Natural {Realism). 
 
 Reason. This term does not very frequently occur in Hamilton. It is 
 usually equivalent to the Elaborative Faculty together with the Re- 
 gulative Faculty. Reasoning refers to the Elaborative Faculty alone. 
 Understanding seems also to refer chiefly to the Elaborative Faculty. 
 
 Rediniegeation. a law of Association. Hamilton seems to give this 
 name to one law of Association in his Lectures and to a different 
 law in his Edition of Reid, as explained in the text. The name ot 
 the law is derived from the tendency of association to re-unite what 
 had once been united, by recalling the rest when any portion of it is 
 present. 
 
 Regulative (Faculty). Hamilton gives this name to the Mind con- 
 sidered as the source of universal and necessary truths. It is not, 
 properly speaking, a faculty, but a collection of a priori laws or 
 principles. 
 
 Relation, Relative. These terms would hardly need explanation, were 
 it not that some writers have used the term relative in the sense of 
 relative to us, and even interpret relative to ns as equivalent to existing 
 only as a state of consciousness in us, or as the cause of such a state 
 of consciousness. This is not Hamilton's use of the terms. When he 
 intends by relative, relative to us, the words to us are, I believe, 
 always added. Hamilton holds that every relation is restrictive or 
 limitative, and hence incompatible with the Infinite. See Infinite ; 
 Conditioned. 
 
 Repetition. See Association. 
 
 Repeesentative (Faculty), Representation. See Imagination. The 
 representative theory of perception, or representative hypothesis has 
 been explained under the head Cosmothelic (Idealism). 
 
 Reproductive or Resuscitative (Faculty). The active faculty of 
 memory — that which recals a mental state which we once felt before, 
 as distinct from the Conservative Faculty, which keeps it latently in 
 the mind ready to be recalled on the proper occasions. 
 
 Retention. See Conservative (Faculty). 
 
 Self. See Ego. Not-self is, of course, equivalent to Non-ego. 
 
 Sensation. See Perception. 
 
 Space. See Extension. 
 
 Species. This word is used in two senses ; first, for a class of things 
 which is not the highest, but has another class above it, as man is a 
 species of animal ; and secondly, nearly in the widest sense of idea, for 
 
GLOSSARY OF PHILOSOPHICAL TERMS. 191 
 
 a mental modification of any kind, which was called a sensible species 
 when it belonged to the senses, and an intelligible species when it 
 referred to the intellect. Sensible species included visible, tangible, 
 &c., species. In this latter sense the word occurs in Hamilton only 
 in a historical reference. 
 
 Subject, Subjective. Besides its use in contrast to the word object (in 
 which case the subject is the mind), this word is used in two other 
 references. In a judgment or proposition, that respecting which the 
 assertion is made is called the subject, and that which is asserted of 
 it is called the predicate ; and again, subject is sometimes used in the 
 same signification as substance, and is thus applicable alike to matter 
 and mind. See Object, Objective. Subjective parts are sometimes 
 used for the parts of which the comprehension of a concept is made 
 up in contrast to integrant parts. 
 
 Substance. Is used by Hamilton for the thing as it really is (which is 
 unknown to us), in contrast to its states or modes which are known 
 to us. These states or modes, however, are not to be regarded as 
 entities inherent in the substance, but as determinations of it. 
 
 Suggestion. Hamilton uses this term occasionally for Reproduction. 
 Reid used it to indicate anything that is not directly attained by 
 consciousness but is called up by that which is directly attained. 
 
 Syllogism. Three judgments or propositions, so arranged that one follows, 
 or is alleged to follow, from the other two. These two are called 
 the premisses, and that which follows from them is called the con- 
 clusion. Ordinarily there must be but three terms in the three 
 propositions, which have been already described as the major, the 
 minor, and the middle, terms. The syllogism is a valid s3'llogism, if 
 the conclusion really follows from the premisses, and invalid if it does 
 not. In Hamilton's system, if the two premisses contain but three 
 terms there will always be some conclusion, unless both premisses 
 are negative or the middle term is undistributed. See Major, Minor, 
 Middle. 
 
 Synthetical. See AmpUative. 
 
 Thought. See Conception; Elaborative (Faculti/] ; Intuition. 
 
 Unconditioned. The opposite of the Conditioned. It includes two 
 sub-divisions which are opposed as contradictories, viz. the uncon- 
 ditionally limited or Absolute, and the unconditionally unlimited or 
 Infinite. See Absolute ; Infinite. 
 
 Univeesal, Universality. Any general notion or concept is often 
 spoken of as an universal, and the corresponding term as an -universal 
 term. This kind of universality must not be confounded with the 
 universality which (with necessity) constitutes Hamilton's test of an 
 
192 GLOSSARY OF PHILOSOPHICAL TERMS. 
 
 a priori or ultimate mental element ; otherwise every general notion 
 or concept would be a priori. An universal proposition is one in 
 which the subject is taken in its entire extension, as All men are 
 mortal, No man is a quadruped. (The quantification of the predicate, 
 however, parti}' abolishes this use of the word universal). In these 
 cases the subject is said to be taken univer.-iall^', which is different 
 from saying that it is an universal term. An universal term might 
 be taken particularly, as Some men are black. Man or men is here an 
 universal term, though taken particularly. The nniversalitj' ascribed 
 to an ultimate or apriori truth is two- fold. 1. It admits of no excep- 
 tions. 2. It is believed by all men. Thus Every event has a cause is 
 true of all events without exception, and all men (on this theory) 
 believe it to be true. 
 Whole. There are man}' kinds of wholes and parts. A sensible object, 
 such as an individual man, is a whole, and even a whole which may 
 be regarded as made up either of integrant, or of subjective, parts ; 
 i.e. as either made up of arms, legs, head, &e., or of size, figure, colour, 
 weight, &c. Besides this, a class or collection of objects may be 
 regarded as a whole, of which the various sub-classes or individual 
 objects comprised in it constitute the parts, and a concept may be 
 regarded as a whole, of which the various attributes comprised in its 
 comprehension make up the parts. Thus (the class) Man is a whole 
 made up of Caucasians, Negroes, Red Indians, &c., and (the concept) 
 Man is a whole, made up of the attributes (or collections of attributes) 
 Rational, Animal, &c. These latter wholes are spoken of as the wholes 
 of comprehension and of extension respectively ; and Hamilton some- 
 times speaks as if the concept was the whole in each case, and as if it 
 might be said (though from different points of view) to consist of either 
 of these kinds of parts. Previous to his adoption of the quantification 
 of the predicate he described every judgment or proposition as ex- 
 pressing a relation of whole and part between the subject and the 
 predicate, either as regards comprehension or as regards extension ; 
 but that theory does away with the relation of whole and part, at 
 least in the case of extension, since in every affirmative j udgment the 
 quantified predicate and subject are declared to be eg^ual as regard* 
 the quantity of extension. 
 
 THE END. 
 
ENGLISH PHILOSOPHERS. 
 
 Edited by IWAN MULLER, A.M., 
 
 New College, Oxford. 
 
 The objects of the proposed Series are : — 
 
 (i) To present, in a connected and historical form, a view 
 of the contributions made to Pliilosophy by English thinkers, 
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 EDITOR'S PREFACE. 
 
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ENGLISH PHILOSOPHERS. 
 
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 Dr. Hill, will be sufficient to attract their attention. * * * In his " True Order of 
 Studies " we have, in plain, simple English, the most practical, compact, and at the 
 same time, profoundly philosophical exposition of the fundamental processes of educa- 
 tion it has been our fortune to meet in any language." — New England Journal 0/ 
 Education. 
 
 " Full of the most valuable and practical suggestions for earnest and intelligent 
 teachers." — Louisville Courier-yottrnal. 
 
 BRACKETT (Anna C.) The Education of American Girls. 
 
 i2mo, cloth, . . . . . . . . ■ I 75 
 
 " The most remarkable, valuable, and interesting volume that has appeared 
 
 upon the subject." — Hartford Post. 
 
 " Characterized by comprehensiveness, learning, candor, and sense.*' — Christian 
 
 Union. 
 
 CALDERWOOD (Henry) Professor of Moral Philosophy in the Uni- 
 sity of Edinburgh, author of " The Philosophy of the Infinite," etc. 
 On Teaching: Its End and Sleans. i2mo, cloth, . i 25 
 " A book of practical value ; Multum in parvo. Should be in the hands of 
 
 every teacher and parent." — Syracuse yournal. 
 
 PUTNAM. The Best Reading. A Classified Bibliography 
 for Easy Reference. With hints on the Selection of Books ; 
 on the Formation of Libraries, public and private ; on Courses of 
 Reading, etc. A Guide for the Librarian, Bookbuyer, and Book- 
 seller. The Classified Lists, arranged under about 500 subject head- 
 ings, include all the most desirable books now to be obtained, either 
 in Great Britain or the United States, with the prices annexed. New 
 Edition, corrected and enlarged. l2mo, paper, 1.25 ; cloth, i 75 
 
 "The best work of its kind we have seen."— College Courant. 
 '' We know of no manual that can take its place as a guide to the selection of a 
 library." — N. Y. Independent. 
 
 ARmiTAGE (E. S.) The Childhood of the English Nation ; 
 or. The Beginnings of English History. j2mo, cloth, 125 
 
 " It would be quite impossible for us to praise this little book beyond us de- 
 serts. It does admirably what it attempts. * * * One of the very best of the recenl 
 histories for both young and old," — Christian Register. 
 
 "The author has thought out her subject honestly and thoroughly, and has 
 ffiven us the result in a clear and qnractive shape " — Saturday Re^fiew 
 
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