DUKE 
 
 UNIVERSITY 
 
 LIBRARY 
 
 Treasure %oom 
 
C O M P E h 
 
 J? OF 
 
 LOGICK : 
 
 FOR THE USE OF THE 
 
 U N I V E R SIT* 
 
 O V 
 
 PENNSYLVANIA. 
 
 By JOHN ANDREWS, D. D. 
 Vice Provost of the University. 
 
 PHILADELPHIA : 
 
 PRINTED BY BUDD AND BARTRAM, 
 
 FOR THOMAS DOBSON, AT THE STONE HOUSE, 
 NO. 41, SOUTH SECOND STREET. 
 
 l80I. 
 
PREFACE. 
 
 KJ¥ the few treatifes of Logick 
 which the author of the following 
 compilation has perufed, Duncan's 
 has always appeared to him to be 
 the befl. But this treatife, however 
 excellent, is for the mod part too 
 diffufive, and in fome places, per- 
 haps, even too fcientifick, for the 
 ufe of young beginners ; at the fame 
 time that it omits a number of par- 
 ticulars, of which (as they are gene- 
 rally 
 
PREFACE, 
 rally taught in the fchools, and oc- 
 cafionally alluded to in converfation 
 as well as books) a teacher would 
 not wilh his pupils to be wholly ig- 
 norant. To obviate thefe objections, 
 and yet retain as much as poffible 
 the features of Duncan, is the aim 
 of the prefent Compend ; which was 
 compofed fome years ago, and is now 
 printed that the claries, for whofe ufe 
 it was intended, may no longer have 
 the trouble of tranfcribing it. 
 
A 
 
 C O M P E N D 
 
 OF 
 
 LOGICK. 
 
 -LOGICK is that fcience which explains 
 the operations of the human undemand- 
 ing, in acquiring and communicating 
 knowledge. And as thefe have been 
 ufually ftated to be four, — apprehend- 
 ing, JUDGING, REASONING, and AR- 
 RANGING our thoughts in a fuitable 
 manner ; fo Logick, which treats of 
 thefe operations, is ufually divided into 
 four parts. 
 
 B P \ 
 
( io ) 
 PART I. 
 
 Of Simple Apprehenfion. 
 
 Simple apprehenfion being that ope- 
 ration of. the mind by which it is furnifh- 
 cd with ideas, a treatife on it, is, in a 
 great meafure, a treatife on ideas, and 
 on the procedure of the mind with re- 
 fpecr to them : and it is alfo a treatife on 
 words and definitions ; becaufe, without 
 thefe, we fliould often be at a lofs both 
 in acquiring and communicating our ideas. 
 The firfl: part, therefore, of Logick, may 
 be divided into two chapters : One treat- 
 ing of ideas ; and the other, of terms 
 and definitions. 
 
 CHAP. 
 
( « ) 
 
 CHAP. 1. 
 
 Of Simple Apprehenfion, and the faculties 
 by which it is exerted : — Of Ideas, or 
 the first principles of Knowledge : — Of 
 the fources from which they are derived ; 
 and of the different forts of them. 
 
 Simple Apprehension is that ope- 
 ration of the underftanding by which it 
 attends to, and notices, the fevcral ob- 
 jects that are prefented to it. It is cal- 
 led fimple apprehenfion, becaufe it is em- 
 ployed in the mere apprehending or no- 
 ticing of things : without comparing 
 them with each other, or aligning to 
 them any attributes ; which is the pro- 
 vince of judgment. And by this operation 
 it is, that the mind, as we have already 
 obferved, is furniihed with ideas : for 
 
 without 
 
( M ) 
 
 without previoufly attending to, and no- 
 ticing, the objects that are prefented to 
 it, it is impoffible that the mind fhould 
 ever have any ideas of them ; or, in 
 other words, be able to reprefent to it- 
 felf the appearances which they ex- 
 hibit. 
 
 In performing this operation, two facul- 
 ties are made ufe of, which are quite 
 diftinct from each other ; sensation, 
 and consciousness. If the object oc- 
 curring be an external thing, the mind 
 perceives it, and its qualities, by means 
 of the fenfes ; and the power of doing 
 this is called the faculty of sensa- 
 tion : if it be an internal thing, that is, if 
 it be any operation or emotion of the mind, 
 the mind attends to and notices it, with- 
 out making ufe, fo far as we know, of 
 any bodily organ ; and it is this power, 
 
 which 
 
 I 
 
( ft ) 
 
 which we call the faculty of con- 
 sciousness. 
 
 The term idea is derived from the 
 Greek word e</£, I fee ; and by ideas are 
 meant, the views which the mind takes 
 of things, when they are no longer pre- 
 fent. In the language of the fchools, 
 ideas are the types or refemblances of 
 things ; and things themfelves are the 
 archetypes, or originals of which the 
 refemblances are made. When an ex- 
 ternal object is prefent, and attended to 
 by my mind, I am faid to perceive it; 
 and when my mind is engaged in any 
 operation, or agitated by any paflion or 
 emotion, I am faid to be conscious of 
 that operation, or of that paflion or 
 emotion : but when the external object 
 is no longer prefent, fo as to affect the 
 organs of fenfe, — or when the operation 
 which had engaged my mind has ceafed 
 
 to 
 
C H ) 
 
 to engage it, or the pafiion or emotion, 
 by which I was agitated, now agitates 
 me no more, — I am capable of thinking 
 of the object which 1 before perceived, 
 or of the operation or emotion of which 
 I was confcious, and of reprefenting to 
 myfelf the appearances which they re- 
 fpe&ively exhibited ; and when I do fo, 
 I am faid to have ideas of them. 
 
 It has been flated, that all external 
 things and their qualities are noticed by 
 means of the fenfes ; and internal things, 
 that is, the operations and emotions of 
 the mind, by confcioufnefs : now all 
 the objects of which we have any know- 
 ledge, are either external things and 
 their qualities, or the operations and 
 emotions of the mind : and, confequent- 
 Jy, all our ideas, how numerous foeyer 
 they may be, are derived from thefe two 
 fources. 
 
 As- 
 
( 15 ) 
 
 As ideas are the firfl elements of all 
 our" knowledge ; fo fenfation and con- 
 fcioufnefs are the firft of our intellectual 
 faculties which are exerted by us. And, 
 again, we can have no ideas of the opera- 
 tions of our own minds until they are 
 exerted ; nor can they be exerted, he- 
 fore the mind is furnifhed with ideas, 
 about which to employ them : • but 
 the ideas which give the firft employ- 
 ment to our faculties, are evidently the 
 ideas of external things, communicated by 
 the fenfes : whence it is plain, that all our 
 knowledge mufl begin in fenfation ; and 
 that the operation of this faculty is prior 
 even to that of confeioufnefs. 
 
 Ideas are either simple or complex. 
 A fimple idea is an idea of a fimple object ; 
 that is, of an object without parts : or it 
 may be defined, an idea which cannot 
 be refolved into two or more ideas. A 
 
( x6 ) 
 
 complex idea is an idea of a complex 
 object ; that is, of an object that confifts 
 of parts : or, it is an idea, that may be 
 refolved into two or more ideas. 
 
 To the former of thefe claffes belong 
 all our ideas of qualities, and of the 
 operations and emotions of our own 
 minds. The qualities of external things 
 are called sensible qualities ; and 
 may be reduced to five general heads, 
 according to the feveral fenfes which are 
 affected by them. Light and colours 
 are perceived by the eye ; founds, by the 
 ear; taftes, by the tongue; fmells, by 
 the nofe ; and heat and cold, roughnefs 
 and fmoothnefs, hardnefs and foftnefs, 
 &c, by the touch. Extenfion, figure, 
 reft, and motion, we perceive by two 
 fenfes ; feeing, and feeling. To which 
 may be added, that our ideas of pleafure 
 and pain, of power, exiftence, unity, 
 
 and 
 
( *7 ) 
 
 and fuccefllon, are conveyed into our un- 
 derstandings both by fenfation and con- 
 fcioufnefs ; that is, both by the action of 
 objects around us, and the confcioufnefs 
 of what we feel within. 
 
 To this general view of our fimple 
 ideas may be fubjoined the two follow- 
 ing obfervations. The first is, that fim- 
 ple ideas can only be conveyed into the 
 mind by the proper channels and avenues 
 provided by nature ; infomuch that if 
 we are deflitute of any of thofe inlets, 
 all the ideas, thence arifing, are abfo- 
 lutely loft to us ; nor can we, by any 
 quicknefs of underftanding, find a remedy 
 for this want. A man born blind is in- 
 capable of ideas of light and colours \ 
 as one, who is born deaf, can form no 
 conception of founds. And hence it ap- 
 pears, that thefe our fimple ideas are 
 iufl fuch as nature furmlhes them, and 
 
 i,-. 
 
( i8 ) 
 
 have no dependence on our will : we can 
 neither deftroy them when in the under- 
 standing ; nor fafhion or invent any new 
 one, not taken in by the ordinary means 
 of apprehennon. So that the utmoft 
 bounds of human knowledge cannot ex- 
 ceed the limits of our fimple ideas and 
 their various combinations. The fecond 
 is, that though the mind, in multiplying 
 its conceptions, can avail itfelf of no 
 other materials than thofe which are fur- 
 niflied by fenfation and confeioufnefs ; 
 vet, as it has a power of combining 
 thefe materials in a great variety of 
 ways, it finds itfelf in poiTeiTion of an 
 inexhauftible treafure of ideas, fufficient 
 to employ it to the full extent of its 
 powers. 
 
 Complex ideas are of two forts : those 
 
 WHICH ARE CONVEYED INTO THE MIND 
 BY THINGS REALLY EXISTING IN NA- 
 TURE 'y 
 
( 19 ) 
 
 ture ; and those which are the 
 
 WORKMANSHIP OF THE MIND ITSELF. 
 
 Things really exifting in nature are all 
 comprifed under the general name of 
 substances ; which are either material 
 or immaterial. And the ufual definition 
 of a fubftance is, that it is a thing which 
 fubfifts of itfelf, without dependence 
 upon any created being, and is the fub- 
 ject of modes. The idea, for example, 
 of a material fubftance includes in it the 
 idea of a thing fubfiiling of itfelf ; and the 
 ideas of its qualities, by which only, as 
 we find by experience, it is made known 
 to us : the idea of an immaterial fub- 
 ftance, in like manner, includes the idea 
 of a thing fubfifting of itfelf; and the 
 ideas of its operations, by which only, 
 as we alfo find by experience, it is made 
 known to us. Whence it appears, that, 
 whether the fubftance be material or im- 
 material, 
 
C 20 ) 
 
 material, the thing itfelf is unknown to 
 us ; and that they are the qualities only 
 of bodies, and the operations of mind, — 
 or, in other words, the modes only or 
 attributes of things, — with which we are 
 acquainted. 
 
 Modes are divided into essential 
 and accidental. An eflential mode 
 is that which cannot be feparated from 
 its fubjecl:, without deftroying the na- 
 ture of the fubjecl: : an accidental mode 
 is that which may be feparated from its 
 fubjecl:, and the nature of its fubjecl: re- 
 main the fame as it was before. Round- 
 nefs, for example, is an effential mode 
 of a bowl ; becaufe a thing cannot be a 
 bowl without being round : but any par- 
 ticular colour is an accidental mode of a 
 bowl j becaufe if a bowl, or a ball, which 
 is now blue, were to be painted white, it 
 would flill be a bowl as much as ever. 
 
 Effential 
 
( jm ) 
 
 Effential modes are divided into pri- 
 mary and secondary. A primary ef- 
 fential mode is that which is derived 
 from no other mode, and conftitutes a 
 thing what it is. A fecondary effential 
 mode is that, which, although infepa- 
 rable from its fubjecl:, is derived from 
 fome other mode. Thus roundnefs is a 
 primary effential mode of a bowl ; be- 
 caufe we do not conceive of it as derived 
 from any other quality of a bowl : but 
 volubility, or aptnefs to roll, is a fecon- 
 dary effential mode of a bowl ; becaufe 
 it arifes from another quality of it, that 
 is, its roundnefs. The primary effential 
 mode has been called differentia, or the 
 difference ; the fecondary effential mode, 
 proprium, or a property ; and the acci- 
 dental mode, accidens. 
 
 Complex ideas which are the work- 
 manfhip of the mind are divided into com- 
 pound, — 
 
( 22 ) 
 
 POUND, UNIVERSAL, GENERAL, Or AB- 
 STRACT, — and RELATIVE. 
 
 Compound ideas are thofe, which the 
 mind forms by putting two or more 
 ideas together. Thefe combinations are 
 fometimes made by adding they^^ idea 
 to itfelf: thus, by adding the idea of 
 unity to itfelf repeatedly, and retaining 
 the feveral amounts in our minds, we 
 come by all the different combinations of 
 numbers : in the fame way are formed 
 the different ideas of yards, perches, fur- 
 longs, miles, leagues, &c. ; alfo thofe 
 of weeks, months, years, &c. But, 
 more frequently, our compound ideas 
 are formed by combining ideas of a dif- 
 ferent kind together. The compofer of 
 mufick, for example, forms the idea of a 
 tune which he is compofmg, — and the 
 mechanick, the idea of a machine which 
 lie is projecting, — -by bringing together, 
 
 in 
 
( 23 ) 
 
 in the former cafe, a number of notes— 
 and, in the latter, of parts, — that are dif- 
 ferent from each other. 
 
 An abflracl:, univerfal, or, as it is 
 more commonly called, a general idea, 
 is an idea that will apply to feveral 
 individuals, or to feveral clafTes of in- 
 dividuals. If it apply to individuals only, 
 the clafs, which correfponds to it, and 
 comprehends individuals, is termed a 
 species ; if to feveral clafTes of indivi- 
 duals, the clafs which correfponds to it, 
 and comprehends thefe feveral clafTes of 
 individuals, is termed a genus. The 
 formation of thefe ideas depends on a 
 power which the mind pofTcfTes of re- 
 moving, from its idea of any object, 
 what .is peculiar to that object ; from its 
 idea of an individual, whatever is pecu- 
 liar to that individual ; and from its ideas 
 of a fpecies, whatever is peculiar to that 
 
 fpecies : 
 
( *4 ) 
 
 fpecies : a power, which, by the writ- 
 ers on the human mind, is called the 
 
 FACULTY OF ABSTRACTION. And 
 
 hence it appears, that it is not without 
 reafon, that our general ideas are ranked 
 among thofe which are the workmanihip 
 of the mind, and have nothing in nature 
 to which they correfpond. 
 
 But that this may be better under- 
 ftood, it will be worth while to take a 
 more diftincl: view of the procefs of the 
 underftanding in the formation of thefe 
 ideas. All the things in nature are in- 
 dividual things : that is, every thing is 
 itfelf, and one ; and not another, and 
 more than one. . But when we come to 
 take a view of the feveral individuals, 
 and obferve that a number of them re- 
 femble each other in one or more par- 
 ticulars of importance, felecting the par- 
 ticulars in which they agree, and remov- 
 
• ( 2J ) 
 
 ing all thofe in which they disagree, we 
 frame to ourfelves a general idea appli- 
 cable to ftveral individuals ; that is, to 
 a particular fpecies. Thus certain ani- 
 mals being found to refemble each other 
 in having an erect form, and in being 
 endowed with the faculties of reafon and 
 fpeech, we take thefe important particu- 
 lars which are common to thein all, and 
 excluding what is peculiar to each, we 
 form a general idea, to which we give 
 the name of man ; and this name belongs 
 equally to every individual who is pof- 
 feffed of the form and faculties above 
 mentioned. This is the firft flep or gra- 
 dation in the forming of abftract ideas, 
 when the mind confines itfelf to the con- 
 sideration of individuals, and frames an 
 idea th.Lt comprehends fuch only under it. 
 Again : having ranged things into fpe- 
 cies, according to the refeniblance fcv.nd 
 D a r 
 
( 26 ; 
 
 among them, we begin to compare the 
 ieveral fpecies with each other ; and 
 often obferve, in thefe alfo, a refem- 
 blance, in one or more particulars of im- 
 portance. Upon this, throwing out all 
 the particulars in which they difagree, 
 and retaining thofe only, in which there 
 is a refemblance, we frame a ftill more 
 general idea, comprehending under it 
 Ieveral fpecies. Thus, a fparrow, a hawk, 
 an eagle, &c. , are diftincl fpecies of birds : 
 They neverthelefs refemble each other 
 in being covered with feathers, and pro- 
 vided with wings which bear them through 
 the air : Out of thefe particulars we 
 form a new idea, and appropriating to it 
 the name bird, mark by that word a 
 higher clafs, which comprehends in it all 
 the former. This higher clafs, which 
 extends to feveral fpecies of things, is 
 called a genus ; and is the fecond flep 
 
 which 
 
( 2 7 ) 
 
 which the mind takes in the formation of 
 it's general ideas. 
 
 But, in rifing from particulars to ge- 
 nerals, the mind does not confine itfelf to 
 one or two gradations. For when wc 
 have reduced things into fpecies, and 
 thefe again into genera, thefe genera are 
 often found to refemble each other in 
 fome particulars, which being combined 
 together into one idea includes a new and 
 more comprehenfive clafs of things. Thin 
 bird is a genus, comprehending the fe- 
 veral fpecies of fparrow, hawk, eagle, 
 &c. : fifh is a genus, including the feveral 
 fpecies of living creatures which inhabit 
 the waters, as dolphins, fturgeons, &c. : 
 beafl or quadruped, and infect, are alfo 
 genera, which extend to many fpecies : 
 yet all thefe different genera have this in 
 common, that they are provided with 
 organical bodies fitted for the purpofes of 
 
 life 
 
( 28 ) 
 
 life and fpontaneous motion. An idea, 
 therefore, made up of thefe particulars 
 only, will comprehend all the genera 
 above mentioned ; and the word, animal, 
 by which it is expreffed, becomes a ge- 
 neral name for the feveral creatures en- 
 dued with life, fenfe, and fpontaneous 
 motion. 
 
 Further : all things, animate and in- 
 animate, refemble each other in this ref- 
 pecl:, that they are created ; whence we 
 refer them to a genus (till higher, which 
 'may be called creature: a name, which 
 belongs equally to every genus and fpecies 
 of created things, and to each individual 
 thing that is created. 
 
 And further dill : all things, what- 
 ever, exift, or are ; and in this refpecl: 
 aue faid to refemble each other : in which 
 view we refer them to a genus flill higher, 
 
 called 
 
( =9 ) 
 
 called Being 9 which is the higheft poflible 
 genus. 
 
 In a feries of genera, riling in this 
 manner one above another, each fuccef- 
 five genus is called, in the fchools, a 
 
 GENUS GENERALIUS, Or HIGHER GENUS; 
 
 and the genus by which each feries is 
 terminated, they diflinguifh by the name 
 
 Of GENUS GENERALISSIMUM. In like 
 
 manner, the feveral genera, comprehend- 
 ed under a higher genus, are, in refpect 
 to it, confidered as fpecies ; and as thefe 
 have alfo fpecies under them, the inferior 
 divifions are, for the fake of diftin&ion, 
 termed species specialiores, or low- 
 er species. And the lowefl: fubdivifions 
 of all, comprehending only individuals, 
 (which, as has been already mentioned, 
 conftitute the proper fpecies) are, in ref- 
 pec"r. to the feries, denominated the 
 species specialissim^e. All that lie 
 
 between 
 
( 3° ) 
 between thefe and the higheft diftribution 
 of things, or genus general illinium, are 
 
 the INTERMEDIATE GENERA AND SPE- 
 CIES ; which are termed fucceffively genus 
 generalius, or fpecies fpecialior, accord- 
 ing as we conflder them in the afcending, 
 or defcending, feries of our ideas ; or, to 
 fpeak in the language of logicians, accord- 
 ing to their afcent, ; or defcent, in the 
 line a pradicamentali. 
 
 And here we may take occafion to 
 mention merely, that, by the ancient 
 writers of logick, a genus general illinium, 
 with all its divifions and fubdivifions, was 
 termed a category, or predica- 
 ment. And as Ariflotle fancied, that 
 all the things in nature might be reduced 
 to ten general heads, or clalfes, namely, 
 fub stance, quantity, quality, relation, ac- 
 tion, pajfion, place, time, fituation, and 
 
 cloathing ; 
 
( 3i ) 
 
 cloathing ; thefe have been called the 
 
 TEN CATEGORIES. 
 
 It is of more importance to remark, 
 that, though many of our general ideas 
 are evidently combinations of different 
 fimple ideas, and in that view of them 
 are included in the clafs of compound 
 ideas, we are carefully to diftinguifh 
 between an idea as it is compound, and 
 as it is general or univerfal. 
 
 An idea is termed compound, with 
 refpect to the feveral ideas which are 
 combined in it ; general or univerfal, 
 with refpecl: to the individuals, fpecies, 
 or genera, to which it extends. Thus the 
 idea of a bird, confidered as a compound 
 idea, includes life, fenfe, fpontaneous 
 motion, a covering of wings, feathers, 
 &c. : but, as a general idea, it denotes 
 the feveral fpecies of the feathered crea- 
 tion, the hawk, the eagle, the lark, &o; 
 
 to 
 
( 32 ) 
 
 to air which it extends with equal pro- 
 priety. In the former cafe, the feveral 
 parts of the compound idea are called its 
 comprehension; in the- latter, the 
 genera, the fpecies, and the individuals, 
 to which the univerfal idea may be ap- 
 plied, are called its extension. 
 
 The third and lad divifion, of thofe 
 complex ideas which are the workman- 
 ship of the mind, confifts of our relative 
 ideas. A relative idea, is an idea which 
 arifes from the comparing of things, one . 
 with another. For the mind is not limit- 
 ed to the confideration of objects, as they 
 are in themfelves merely ; but can ex- 
 amine them as connected with other things 
 brought into view at the fame time. And 
 when it does fo, and thence acquires new 
 ideas, the ideas thus acquired are called 
 relative ideas ; and make, as is fuppofed, 
 the largeft clafs of our ideas. For every 
 
 fmgle 
 
( 33 ) 
 
 fingle objeft will admit of almofl: innume- 
 rable companions with others, and, in 
 this way, may become a very plentiful 
 fource of ideas to the undemanding. 
 Thus, if we compare one thing with 
 another in refpect to bulk, we get the 
 idea of greater and lefs, or of equality : 
 if, in refpect of time, of older and 
 younger : and fo of other relations, which 
 we can purfue at pleafure, and almofl 
 without end. 
 
 So much, with refpecl to ideas; which 
 are the fubject of the firfh chapter. We 
 have Mated, that all our fimple ideas arc 
 conveyed into the underftanding either 
 by fenfation or confeioufnefs ; and are 
 the materials out of which all others are 
 formed: that the mind, though it has 
 no power over thefe, either to fafhion 
 or to deftroy them, can yet combine them - 
 in an infinite number of ways ; and that 
 E from 
 
( 34 ) 
 
 from their various combinations refult all 
 our complex ideas : that thefe complex 
 ideas are of two principal kinds ; firft, 
 fuch as are derived from without, andre- 
 prefent thofe combinations of fimple ideas 
 that have a real exiflence in nature, — 
 of which fort are all our ideas of fub- 
 flances ; fecondly, fuch as are formed by 
 the mind itfelf, arbitrarily uniting and 
 putting together its ideas : and that, as 
 thefe lad make by far the largeft clafs, 
 and comprehend all thofe ideas which 
 may be properly termed our own, as 
 being the workmanfhip of the under- 
 flanding ; fo they fall very naturally un- 
 der three diftincT: heads. For either the 
 mind combines feveral fimple ideas toge- 
 ther in order to form them into one com- 
 plex idea, in which the number and 
 quality of the ideas united are principally 
 confidered ; in which way we become 
 
 poifeffed 
 
( 55 ) 
 
 porTeffed of all our compound ideas : or 
 it fixes upon any one of its ideas, whe- 
 ther it be a fimple or compound idea, or 
 an idea of a fubltance, and leaving out 
 the circumftances of time, place, real 
 exigence, and whatever renders it par- 
 ticular, confiders what it has in common 
 with others, and of that makes an idea 
 which will apply to all of a kind ; whence 
 our abdracl or univerfal ideas are deriv- 
 ed : or, laflly, it compares things one 
 with another, examines their mutual con- 
 nections, and thereby furniihes itfelf with 
 a new fet of ideas, known by the name 
 of relations ; which, as has been already 
 remarked, make by no means the leaf] 
 important clafs of our ideas. 
 
 CHAP. 
 
. ( 3« > 
 
 CHAP. II. 
 
 Of Terms and Definitions. 
 
 Having feen, in the preceding chap* 
 ter, how our ideas are acquired ; let us 
 now proceed to examine how they are 
 communicated. Ideas themfelves are not 
 vifible, nor can they be perceived by any 
 outward fenfe. But God, defigning us 
 for fociety, and to have fellowship with 
 thofe of our kind, has provided us with 
 organs fitted to frame articulate founds, 
 and given us alfo a capacity of ufing 
 thofe founds, or terms, as figns of ideas. 
 Hence our ideas, which otherwife muft 
 have been locked up, as it were, in our 
 own breads, are brought forth and made 
 to appear. For, any number of men 
 having agreed to make ufe of the fame 
 
 founds 
 
( 37 ) 
 founds as figns of the fame ideas, it is 
 evident, that the repetition of thefe 
 founds mud excite the fame ideas in them 
 all. When, for inflance, any train of 
 ideas takes poffeffion of m,y mind, if the 
 terms, or founds, by which I am wont 
 to exprefs them, have been annexed, by 
 thofe with whom I converfe, to the very 
 fame fet of ideas, nothing is more evi- 
 dent, than that by repeating thofe terms, 
 according to the tenor of my ideas, I 
 fhall raife in their minds the fame train 
 that has taken poffefTion of my own. 
 Hence, by barely attending to what paffes 
 within themfelves, they will alfo become 
 acquainted with the ideas in my under- 
 - Handing, and have them in a manner ex- 
 pofed to their view. 
 
 So that we here clearly perceive how 
 a man may communicate his fentiments 
 to another j provided the language, in 
 
 which 
 
( 38 ) 
 which he converfes, be copious enough 
 to contain words appropriated to all his 
 ideas ; and provided the perfon, to whom 
 he fpeaks, is poffeffed of the fame ideas 
 which he expreffes, and has been ac- 
 cuftomed to connect them with the fame 
 terms. 
 
 But as this is not always the cafe, 
 and as we may often have occafion to 
 communicate to others a new idea, — that 
 is, an idea that has never yet entered 
 their minds, and which confequently they 
 cannot as yet have connected with any 
 term ; it may be alked, how fuch an idea 
 can poffibly be communicated to them, 
 by a term to which they have never an- 
 nexed any idea, and which of courfe can- 
 not be to them the fign of an idea. 
 
 This appears to be a difficulty ; and, 
 to folve it, it will be necelTary to obferve, 
 firft, that no word can be to any man 
 
 the 
 
( 39 ) 
 
 the fign of an idea, till that idea comes 
 to have a real exiftence in his mind. For 
 words being only fo far intelligible, as 
 they denote known ideas ; where they 
 have none fuch to anfwer to them, there 
 they are plainly founds without figniflca- 
 tion, and of courfe convey no informa- 
 tion. But no fooner are the ideas, to 
 which they belong, produced in the un- 
 derstanding, than, finding it eafy to con- 
 nect them with the eftablifhed words, we 
 can join in any agreement of this kind 
 made by others, and enjoy the benefit of 
 their difcoveries. The firlf thing, there- 
 fore, to be confidered, is, how thefe 
 ideas may be conveyed into the mind, 
 that, they being there, we may learn to 
 connect them with the appropriated 
 founds, and fo become capable of under- 
 ftanding others when they make ufe of 
 thefe founds in laying open and communi- 
 cating 
 
( 40 ) 
 
 eating their thoughts. Now to compre- 
 hend diftinctly how this may be done, it 
 will be neceffary to call to mind the be- 
 fore mentioned divifions of our ideas into 
 iimple and complex. And firft, as to 
 our fimple ideas, it has been already ob- 
 ferved, that they can find no admiffion 
 into the mind, but by the original foun- 
 tains of knowledge \ fenfation, and con- 
 fcioufnefs. If therefore any of thefe have 
 as yet no being in the underftanding, it 
 will be impoifible bywords to excite them 
 there. A man, who had never felt the 
 impreffion of heat, could not be brought 
 to comprehend that fenfation, by any 
 thing which we could fay to explain it. 
 If we would produce the idea in him, it 
 muft be by applying the proper object to 
 his fenfes, and bringing him within the 
 influence of a hot body. When this is 
 done, and experience has taught him the 
 
 fenfation, 
 
( 4i ) 
 
 fenfation, to which men have annexed 
 the name, heat, this term then becomes 
 to him the fign of that idea; and he 
 thenceforth underftands the meaning of 
 the term ; which, before, all the words 
 in the world would not have been fuf- 
 ficient to convey into his mind. The 
 cafe is the fame with refpecl: to light and 
 colours : a man born blind, and by this 
 misfortune deftitute of the only convey- 
 ance for the ideas of thefeobj eels, can never 
 be brought to underftand the terms by 
 which they are expreifed. The reafon 
 is plain : they ftand for ideas which have 
 no exigence in his mind ; and as the 
 organ, appropriated to their reception, is 
 wanting, all other contrivances are vain, 
 nor can thefe ideas, by any force of de- 
 fcription, be excited in him. — But, with 
 our complex ideas, it is quite otherwifc. 
 For thefe being no other than certain 
 F eombina- 
 
( 42 ) 
 
 combinations of fimple ideas put together 
 in various forms ; if the fimple ideas, out 
 of which the complex ideas are made, 
 have already got admiflion into the un- 
 derstanding, and the terms ferving to ex- 
 prefs them be known, it will be eafy, by 
 enumerating the feveral ideas included in 
 the combination, and marking the order 
 and manner in which they are united, to 
 raife any complex idea in the mind. Thus 
 the idea anfvvering to the term, rainbow, 
 may be readily excited in the imagina- 
 tion of another, who has never feen the 
 appearance itfelf, by defcribing the fi- 
 gure, frze, pofition, and order of co- 
 lours ; if we fuppofe thefe feveral fimple 
 ideas, with their names, fufflciently known 
 to him. 
 
 The anfwer, then, to the queflion pro- 
 pofed above, is now fufficiently obvious. 
 If the new idea, which we wifh to com- 
 municate 
 
( 43 )' 
 
 municate to others, be a fimple idea, we 
 mult refer them to thofe objects in nature 
 whence the idea is to be obtained : but, 
 if it be a complex idea, its meaning may 
 be explained by enumerating the ideas 
 included in it ; that is, by defining it. 
 
 And here we fee the nature and ufe of 
 definitions. They are ufed to unfold a 
 complex idea ; and two things are re- 
 quired in them : lirfl, that all the fimple 
 ideas, out of which the complex one is 
 formed, be diftinctly enumerated ; and, 
 fecondly, that the order and manner of 
 combining them be clearly explained. 
 Where a definition has thefe requifites, 
 nothing is wanting to its perfection ; be- 
 caufe every one, who reads it, and un- 
 derftands the terms, feeing at once what 
 ideas he is to join together, and alfo in 
 what manner, can, at pleafure, -form, 
 
 in 
 
C 44 ) 
 
 in his own mind, the complex idea an* 
 fwering to the term defined. 
 
 But this rule, though it extends to all 
 poffible cafes, and is indeed that alone to 
 which we can have recourfe where any 
 doubt or difficulty arifes, it is not, how- 
 ever, neceffary, or even expedient, to 
 praclife in every particular inftance. Many 
 cf our ideas are extremely complex ; and, 
 of courfe, to enumerate all the fimple 
 ideas, out of which they are formed, 
 would be a very troublefome and tedious 
 work. For which reafon, logicians have 
 eftabliflied a certain compendious mode of 
 defining ; of which, it may not be amifs 
 to give here a fhort account. If the thing 
 to be defined be a fpecies, they give the 
 
 NEAREST GENUS and the SPECIFICK 
 
 difference ; or, in other words, they 
 refer it to its neareft genus, and then add 
 thofe circumftances that make the fpecies, 
 
 which 
 
( 45 ) 
 
 which they are defining, to differ from 
 every other fpecies belonging to that 
 genus. For, as the idea of a genus is 
 formed by dropping what is peculiar to 
 each of the feveral fpecies referred to it, 
 and retaining thofe particulars which they 
 all poffefs in common ; fo, on the other 
 hand, by adding to the genus what is 
 peculiar to any one of the fpecies includ- 
 ed in it, we form an adequate idea, and 
 give a complete definition, of that fpecies. 
 In like manner, if the thing to be defined 
 be an individual, the logical definition 
 will confilt. of the the species and the 
 numerical difference ; or, in other 
 words, of the fpecies, and thofe particu- 
 lars that diilinguiili the individual which 
 we are defining, from every other in- 
 dividual belonging to that fpecies. For, 
 as the idea of a fpecies is formed by drop- 
 ping what is peculiar to the feveral in- 
 dividuals 
 
( 46 ) 
 
 dividuals referred to it, and retaining 
 thofe particulars only which they polTefs 
 in common ; fo, by adding to the fpecies 
 what is peculiar to any one of the indi- 
 viduals included in it, we form an ade- 
 quate idea, and give a complete defini- 
 tion, of that individual. 
 
 We mail conclude with obferving, that 
 definitions have been diftinguiflied into 
 two kinds ; the definition of the 
 name, and the definition of the 
 thing. When the term to be defined, 
 refers to the idea of the writer or fpeak- 
 er, and the definition is defigned to fhow 
 what idea he connects with a certain 
 term, it is a definition of the name. And 
 fuch definitions are faid to be arbitrary ; 
 becaufe, as words are not natural, but 
 merely artificial, figns of ideas, every 
 man is at liberty to annex to a term what 
 idea he pleafes. But where the reader, 
 
 or 
 
C 47 ) 
 
 or hearer, is fuppofed to know that a 
 certain term is connected with a particu- 
 lar idea, and where the defign of the de- 
 finition is to unfold that idea, that the 
 nature of the thing of which it is the type 
 or refemblance, may be fully underftaod, 
 it is a definition of the thing. And fuch 
 a definition is not arbitrary, becaufe the 
 idea of any thing mould be conformable 
 to that thing, and the definition confor- 
 mable to the idea. 
 
 PART II. 
 
 Of Judgment. 
 
 All our knowledge may be reduced 
 to two heads ; our ideas of things, and 
 the judgments which we form with refpect 
 
 to 
 
( 48 ) 
 
 to them. Of our ideas, and of terms 
 and definitions by which they are commu- 
 nicated, we have already treated. We 
 come now to fpeak of our judgments ; 
 and of propositions, by which they are 
 communicated. And here it will be pro- 
 per to confider, firft, the feveral grounds 
 of human judgment ; and, fecondly, the 
 different forts of propofitions. 
 
 CHAP. I. 
 
 Of the grounds of human judgment ; or, 
 in other words, of the different sorts 
 
 OF EVIDENCE. 
 
 Judgment is that operation of the 
 mind by which we compare two or more 
 ideas together, with a view to determine 
 whether they agree or difagree. But 
 
 alth6ugh, 
 
( 49 ) 
 
 although, in every aft of judgment, it is 
 neceffary to bring two or more ideas 
 together, and place them, as it were, 
 over againfl each other; yet, the mere 
 comparing of two ideas together is not 
 the evidence of their agreement or difa- 
 greement. What then, it may be aiked, 
 is this evidence ? or rather, (^as one fort 
 of truth is fupported by one fort of evi- 
 dence, and another by another), What 
 are the different forts of evidence ? 
 
 To affifl us in judging of this fubjeft, 
 it will be neceffary to obferve, that all 
 the objefts of the human underflanding 
 are, either abstracl notions of quantity and 
 number , or things really existing. Of the 
 relations of thefe abftraft notions, all our 
 knowledge is certain ; being founded on 
 mathematical evidence. Of things really 
 exifting, we judge, either from our own 
 experience, or from the experience of 
 G other 
 
( 5° ) 
 
 other men. Judging of real exiftencc 
 from our own experience, we attain either 
 certainty or probability. Our knowledge 
 of real things is certain, when fupported 
 by the evidence of external fenfe, con- 
 icioufnefs, and memory ; and when from 
 effects we infer caufes. Our knowledge 
 of real things is probable, when, from 
 facts whereof we have had experience, 
 we infer facts of the fame, or a fimilar, 
 kind, not experienced. Judging of real 
 exiflence from the experience of other 
 men, we have the evidence of their tefii- 
 mony. And thus it appears, that aU 
 forts of evidence productive of real know- 
 ledge, may be reduced to feven : i. Ma- 
 thematical evidence, i. The evidence of 
 external fenfe. 3. The evidence of con- 
 fcioufnefs. 4. The evidence of memory, 
 5. That evidence which we have, when 
 
 from 
 
( 5* ) 
 
 from effecls we infer caufes. 6. The evi- 
 dence of testimony, 7. Probable evidence. 
 
 Of IvIATHEMATICAL EVIDENCE there 
 
 are two forts ; intuitive^ and demonstrat- 
 ive. Mathematical evidence is intuitive, 
 when, from the very nature of the ideas 
 compared, it appears, at firfl view, that 
 they mu(t neceflarily agree or difagree. 
 Mathematical demonftrative evidence is 
 direel, or indirtcl. When a conclufion 
 is inferred from principles which render 
 it neceflarily true, the demonflration is 
 direct. When, by fuppofing a given 
 propofition falfe, we are neceflarily led 
 into an abfurdity, it is called indirect, 
 apagogical, or ducens in abfurdum. Now 
 that mud be true, which we cannot, 
 without abfurdity, fuppofe to be falfe. 
 And therefore both forts of demonflra- 
 tion are equally good, becaufe equally 
 productive of abfolutc certainty. 
 
 All 
 
( 52 ) 
 
 All mathematical proof is founded upon 
 axioms, or felf-evident proportions, the 
 contraries of which are inconceivable. 
 And this fort of proof feems to be pecu- 
 liar to the fciences that treat of quantity 
 and number ; and therefore, in no other 
 fcience is the mathematical method of 
 proof to be expected. For, in the other 
 fciences, in moft of them at lead, truth 
 and its contrary are equally conceivable. 
 That Julius Csefar died a natural death is 
 as eafy to be conceived, as that he was 
 murdered in the fenate-houfe. I feel a 
 hard body, I do not feel a hard body ; 
 I fee a white colour, I do not fee a white 
 colour ; are all equally conceivable : and 
 yet may be either true or falfe according 
 to circumftances. We may conceive that 
 the fun, after fetting to-night, will never 
 appear again, or that any particular man 
 will never die : and yet we confider death 
 
 as 
 
( 53 ) 
 
 as what mud inevitably happen to every 
 man, and the rifing of the fun to-morrow 
 as fo certain, that no rational being can 
 doubt of it. Though, therefore, the 
 mathematical method of proof is to be 
 found in the mathematical fciences only, 
 yet fatisfactory proof may be found in 
 any other fcience : and is actually found, 
 in every part of knowledge that deferves 
 the name of fcience. 
 
 The evidence of external sense, 
 no lefs than mathematical evidence, pro- 
 duces abfolute certainty ; though in 
 another way. Our conception of exter- 
 nal things is attended with an irrefiflible 
 belief, that they exift, and are what 
 they appear to be. When I fee a man 
 or a horfe, I can no- more doubt of his 
 exiftence, than of my own ; and my own 
 1 believe with as full aflurance as that 
 two and two are four. The exiftence of 
 
 body 
 
( 54 ) 
 
 body is a felf-evident fact. It needs no 
 proof; for to difbelieve or doubt of it 
 is impoflible : and it admits of none ; 
 becaufe we know of nothing more evident 
 to prove it by. 
 
 The EVIDENCE OF INTERNAL SENSE, 
 
 or consciousness, does alfo produce 
 abfolute certainty. That we have within 
 us a thinking and active principle, called 
 a foul or mind ; which is the fame thing 
 to-day as it was yefterday ; is confcious 
 of its own thoughts ; and exercifes a 
 variety of faculties different in their ob- 
 jects and manner of operation ; are all of 
 them fuggeftions of internal fenfe or con- 
 fcioufnefs, which we believe becaufe we 
 feel them to be true ; and which if we 
 were not to believe, would bring on us 
 the charge of irrationality. 
 
 The evidence of memory does alfo 
 produce abfolute certainty. A child be- 
 lieves, 
 
( 55 ) 
 
 iieves, without any doubt, that, what he 
 remembers diftinclly to have feen or 
 heard, he really did fee or hear. And 
 he believes this, not becaufe he has been 
 told that he may fafely truft his memory j 
 but becaufe the law of his nature deter- 
 mines him, of his own accord, to believe 
 his memory as well as his fenfes. Indeed 
 if we were to diftruft our memory, or 
 treat it as a fallacious faculty, our fenfes 
 would be of little ufe to us, and we 
 fliould be incapable both of knowledge 
 and experience, and alfo of reafoning ; 
 for we cannot be fatisfled with a proof, 
 unlefs we remember the fteps of it, and 
 believe that on that remembrance we 
 may depend. Thoughts remembered 
 may decay through length of time, and 
 at lad vanifh ; but, of an event or object, 
 that part which we diftinc"tl,y remember, 
 we believe to have been real. We may 
 
 forget 
 
( 56 ) 
 
 forget the whole fubjecl: of a book, and 
 yet remember, and confequently believe, 
 that we read it. We may forget the 
 proofs of a propofition, and yet remem- 
 ber that it was formerly proved to our 
 fatisfa&ion, and acquiefce in it accord- 
 ingly. If in conceiving any event or 
 object, we are uncertain whether we re- 
 member or only imagine, belief is fuf- 
 pended and we remain in doubt ; but no 
 fooner are we confcious that we remem- 
 ber, than belief inflantly takes place; 
 and we fay, I am certain it was fo, for 
 now I remember it diftinctly. 
 
 As tO THE EVIDENCE THAT WE HAVE 
 WHEN FROM EFFECTS WE INFER CAUS- 
 ES, we may obferve, that the law of our 
 nature determines us to believe, that 
 whatever begins to exist, proceeds from 
 fome caufe. If, on going home, I mould 
 find, on the table, a book, which I never 
 
 . faw 
 
( 57 ) 
 faw before, it would occur to me as ab- 
 folutely certain, that fome caufe had 
 brought and fome perfon made it. For 
 if I were to be told, that nobody brought 
 it, and that it never was made, I fliould, 
 without hefitation, declare fuch a thing 
 to be not only abfurd but impoffible ; 
 and there is not one rational being who 
 in this would refufe to concur with me. 
 Even children think in this manner, and 
 fome are very inquifitive into the caufes 
 of things : a proof that it is not experi- 
 ence merely which leads us to infer the 
 caufe from the efTecl:. If the book, which 
 I fuppofed myfelf to find, contained wife 
 obfervations, and was well printed and 
 bound, I mud of neceffity believe, that 
 the author, printer, and binder, were 
 pofTeffed of wifdom and /kill equal to the 
 
 efTecl: produced. That being whom we 
 
 believe to have proceeded from no caufe 
 H but 
 
( 58 ) 
 
 but the neceffity of his own nature, and ta 
 be felf-exiftent, and on all other beings in- 
 dependent, we mud alfo believe to have 
 exifted from eternity, or in other words, 
 to have had no beginning. For if every 
 thing that had a beginning, proceeded 
 from fome caufe, that which proceeded 
 from no caufe, could have had no begin- 
 ning. 
 
 Probable evidence is of two forts. 
 One is, when from facts whereof we 
 have had experience, we infer facts of 
 the fame kind not experienced. It is na- 
 tural for us to think, that the courfe of 
 things whereof we have had experience, 
 and now have, will continue, unlefs we 
 have pofitive reafon to believe that it will 
 be altered. This is the ground of many 
 of thole opinions which we account quite 
 certain. That to-morrow the fun will 
 rife, and the fea ebb and flow ; that 
 
 night 
 
( 59 ) 
 
 night will follow day, and fpring fucceed 
 lhe winter ; and that all men will die ; 
 are opinions amounting to certainty : and 
 yet we cannot account for them other- 
 wife than by faying, that fuch has been 
 the courfe of nature hitherto, a£nd we 
 have no reafon to believe that it will be 
 altered. When judgments of this kind 
 admit no doubt, as in the example given 
 above, our conviction is called moral 
 certainty. I am morally certain, that 
 the fun will rife to-morrow, and (ct to- 
 day, and that all men will die, &c. The 
 inftances of part experience, on which 
 thefe judgments are founded, are innu* 
 merable ; and there is no mixture of con- 
 tradictory inftances which might lead us 
 to expect a contrary event. But if the 
 experiences, on which we ground our 
 opinions of this fort, are but few in num- 
 ber, or mixed with contradictory experi- 
 ences, 
 
C 60 ) 
 
 ences, in this cafe we<io not confider the 
 future event as morally certain, but only 
 more or lefs probable according to the 
 greater or lefs furplus of favourable in- 
 ftances.— The other fort of probable evi- 
 dence, which is termed analogical, is, 
 when from facts whereof we have had 
 experience, we infer facts of a Jimilar 
 kind not experienced ; or, in other words, 
 when we expect fimilar events in fimilar 
 circumftances. For example, we think 
 it probable that the planets are inhabited, 
 they being in all refpe&s fo like our earth. 
 The force of an argument from analogy 
 is in proportion to the degree of likenefs, 
 that there is between the caXtfrom which 
 we argue, and the cafe to which we 
 argue. In the example given, the cafe 
 from which we argue, is the circumftance 
 of this earth's being a planet, warmed 
 and enlightened by the fun, and inhabited 
 
 by 
 
f 61 J 
 
 by many varieties of living creatures ; 
 and the cafe to which we argue, is that 
 of the other planets, which being in all 
 other refpe&s fo fimilar to our earth, we 
 think it highly probable that they mufl 
 refemble it in this, in being the habita- 
 tion of percipient beings. A man who 
 thinks, as Epicurus did, that they are 
 no bigger than they appear to his eye, 
 can have no notion of their being inhabit- 
 ed, becaufe to him they mufl: appear in 
 every refpect fo unlike our earth. And 
 if we were to argue with him, in order 
 to bring him over to our opinion, we 
 fhould begin by explaining to him thofe 
 particulars, wherein the earth and the 
 other planets refemble each other. As 
 foon as he underflands thefe particulars 
 as well as we, he will, of his own ac- 
 cord, admit the probability cf our 
 opinion. 
 
 Another 
 
( 62 ) 
 
 Another and the laft -fpecies of evi- 
 dence, upon which we are to remark in 
 this place, is testimony. It is natural 
 for a man to fpeak as he thinks ; and it 
 is eafy, like walking forward. One may- 
 walk backward, or fideways ; but it is 
 uneafy, and a fort of force upon nature : 
 and the fame thing is true of fpeaking 
 one thing and thinking another. — It is 
 alfo natural for us to believe what others 
 feriouily tell us. We truft the word of 
 a man of whofe veracity we have had ex- 
 perience ; but we alfo credit teftimony 
 previoufly to fuch experience ; for child- 
 ren, who have the leafl experience, are 
 the mod credulous. It is from having 
 had experience of the ^difhonefty of men, 
 and of the motives that tempt them to it, 
 that we come to difbelieve or to diftruft 
 what they fay. In general, when we 
 doubt a man's word, we have fome reafon 
 
 for 
 
( 6 3 1 
 
 for it. We think that what he fays is in- 
 credible in itfelf ; or, that there is fome 
 motive or temptation which inclines him 
 in the prefent cafe to violate truth ; or, 
 that he is not a competent judge of the 
 matter in which he gives teftimony ; or, 
 laftly, we diftruft him now, becaufe we 
 know him to have been a deceiver for- 
 merly. 
 
 Faith in teftimony often rifes to ab- 
 folute certainty. Of places and perfons 
 we never faw, and know nothing but 
 from the teftimony of others, we believe 
 many things as firmly as we believe our 
 own exiftence. This happens, when the 
 teflimonies of men concerning fuch places 
 and perfons, are fo many, and fo con- 
 fident, that it feems impoffible they 
 fliould be fictitious. — When a number of 
 perfons, not a&ing in concert, having no 
 intereft to difguife what is true, or to 
 
 affirm 
 
f 64 ) 
 
 affirm what is falfe, and competent judges 
 of what they teftify, concur in making 
 the fame report, it would be accounted 
 folly to difbelieve them, efpecially if what 
 they teflify be credible in itfelf. Even 
 when three, or when two witneffes, fepa- 
 rately examined, having had no oppor- 
 tunity to concert a plan beforehand, 
 concur in the fame declaration, we be- 
 lieve them, though we have had no ex- 
 perience of their veracity ; becaufe we 
 know, that in fuch a cafe their declara- 
 tions would not be confident, if they 
 were not true. — In regard to an impof- 
 fible thing, we mould not believe our 
 own fenfes, nor confequently human tef- 
 timony. Miraculous fa els, however, are 
 not to be ranked with impoilibilities. To 
 raife a dead man to life, to cure blind- 
 nefs with a touch, to remove lamenefs, 
 er a difcafe, by fpeaking a word, are 
 
 miracles : 
 
( 65 ) 
 
 miracles : but to divine power as eafy, as 
 to give life to an embryo, make the eye 
 an organ of fight, or caufe vegetation to 
 revive in the fpring. If it be afked, 
 what evidence is fufficient to eftablifh the 
 truth of miraculous events fuch as thefe, 
 we anfwer, that every event admits of a 
 proof from human teftimony, which it is 
 poffible for a fufficient number of com- 
 petent witnelfes to fee and to hear. 
 
 CHAP. IL 
 
 Of Proportions, and their Various Kinds. 
 
 A proposition is a judgment of the 
 mind expreifed in words. Now as our 
 judgments include at leait two ideas, one 
 of which is affirmed or denied of the 
 other 3 fo muft a proportion have terms 
 1 anfwer in 2 
 
( 66 ) 
 
 anfwering to thefe ideas. The idea, of 
 which we affirm or deny, and of courfe 
 the term expreffing that idea, is called 
 the subject of that proportion. The 
 idea affirmed or denied, as alfo the term 
 anfwering to it, is called the predi- 
 cate. Thus, in the proportion, God is 
 omnipotent^ — God is the fubjecr, it being of 
 him that we affirm omnipotence ; and 
 omnipotent is the predicate, becaufe we 
 affirm the idea, expreiTed by that word, 
 to belong to God. And that word, in 
 a proportion, which connects the fubjecT: 
 and predicate together, is called the 
 copula ; as in the above mentioned pro- 
 portion, where is is the copula, and llg- 
 nifi.es the agreement of the ideas of God 
 and omnipotence. But if we mean to 
 feparate two ideas, then, befides the co- 
 pula we mud alfo ufe fome particle of ne- 
 gation to exprefs this repugnance. Of 
 
 this 
 
f .67 ) 
 
 this kind, the proportion, man is not per- 
 feci, may ferve as an example ; where the 
 idea of perfeclion being intended to be fe- 
 parated from the idea of man, the nega- 
 tive particle not is inferted after the co- 
 pula, to fignify the difagreement between 
 the fubjeft and the predicate. But al- 
 though every proportion neceflarily con- 
 fids of thefe three parts, it is not alike 
 necefTary that they be all feverally exprefs- 
 ed in words ; becaufe the copula is often 
 included in the term of the predicate, as 
 when we fay he writes, which imports 
 the fame as he is writing. And, in the 
 Latin language, a fingle word has often 
 the force of a whole fentence ; where 
 ambulat, for example, is the fame as ilk 
 est ambulans ; amo, as ego Jam amqns. 
 Proportions are either affirmative 
 
 Or NEGATIVE, UNIVERSAL Or PARTI- 
 CULAR, ABSOLUTE 01* CONDITIONAL, 
 
 SIMPLE 
 
( 68 ) 
 
 SIMPLE Or COMPOUND, SELF-EVIDENT 
 Or DEMONSTRABLE, SPECULATIVE Or 
 PRACTICAL. 
 
 An affirmative proportion conne&s the 
 predicate with the fubjecl: ; as, a stone is 
 heavy : a negative feparates them ; as 
 God is not the author of evil. And as, in 
 all cafes, the predicate muft either be 
 connected with the fubjecl:, or feparated 
 from it, it is evident that all proportions 
 fall under thefe two divifions. 
 
 An univerfal proportion is a propo- 
 rtion which has for its fubjecl: fome gene- 
 ral term taken in its full extent ; fo that 
 the predicate agrees with all the indivi- 
 duals comprehended under it, if it be a 
 proper fpecies, — and with all the feveral 
 fpecies and their individuals, if it be what 
 is termed a genus. Thus, all animals 
 have a power of beginning motion, is .an 
 univerfal propofition ; animals, the fub- 
 jecl, 
 
( 6 9 ) 
 
 je<5t, being a general term without any 
 mark of limitation, and by confequence 
 taken in its full extent : hence the power 
 of beginning motion may be affirmed of 
 all the feveral fpecies of animals, as of 
 quadrupeds, birds, infects, fillies, &c. ; 
 and of all the individuals of which thefe 
 different fpecies confift, as of this hawk, 
 that horfe, and fo on with refpedt to the 
 reft. A particular propofition is one, 
 which has, in like manner, fome general 
 term for its fubject ; but with a mark of 
 limitation added, to denote that the pre- 
 dicate agrees with fome only of the in- 
 dividuals comprehended under it, if it be 
 a fpecies, — or with one or more, not 
 with all, of the fpecies belonging to it, 
 if it be a genus. Thus, fome stones are 
 heavier than iron ; fome men have an un- 
 common Jhare of prudence. Where the 
 
 fubject of a propofition is an individual, 
 
 it 
 
i 7° ) 
 
 it is called a singular proposition. 
 Of this nature are the following, Sir 
 Ifaac Newton was the inventor of find ions ; 
 This book contains many ufeful truths. And 
 fach proportions, though more particular 
 than thofe which are generally called (o, 
 come under the fame rule with univerfals ; 
 becaufe, in them, the fubject is taken in 
 its full extent. 
 
 It has been already obferved, that all 
 propofitions are either affirmative or ne- 
 gative : it is equally evident, that, in 
 both cafes, they may be univerfal or par- 
 ticular. Hence arifes that celebrated four- 
 fold divifion of them, into universal 
 
 AFFIRMATIVE, UNIVERSAL NEGATIVE; 
 PARTICULAR AFFIRMATIVE, and PAR- 
 TICULAR negative. And, in forming 
 fyllogifms, it has become a cuftom, in 
 the fchools, to make ufe of the four 
 vowels, a, e, /, o 9 to denote thefe va- 
 rieties : 
 
( 7* ) 
 
 rieties : #, to denote an univerfal affir- 
 mative, as all good men are esteemed ; e 9 
 an univerfal negative, as, no man is in- 
 fallible ; /, a particular affirmative, as, 
 fome men are wife, o 9 a particular nega- 
 tive, as, fome men are not honest. 
 
 " Afferit a, negat e, verum generaliter 
 
 amba:" 
 " Afferit i, negat o, fed particulariter 
 
 ambo." 
 
 The diftinclion of propofitions into uni- 
 verfal and particular, is called their 
 quantity ; and into affirmative and ne- 
 gative, their quality. 
 
 Abfolute propofitions are thofe in 
 .which we affirm, that fome property is 
 infeparable from the idea of the fubject ', 
 as, lead is heavy. Conditional propo- 
 fitions are thofe in which the predicate is 
 not neceffarily connected with the fub- 
 
 jecr, 
 
( 72 ) • 
 
 je&, and can be affirmed of it on fome 
 condition only, diftinft from the idea of 
 the fubjecl: ; as, if a stone be expofed to the 
 rays of the fun, it will contracl a degree 
 of heat. And here we are to obferve, 
 that all conditional proportions confift of 
 two diftincl: parts : one, expreffing the 
 condition upon which the predicate agrees 
 , or difagrees with the fubjecl: ; as, in the 
 example before us, if a stone be expofed to 
 the rays of the fun : the other, joining or 
 disjoining faid predicate and fubjecl: ; as, 
 in the fame example, it will contracl a 
 degree of heat. The firft of thefe parts 
 is called the antecedent \ the fecond, the 
 confequent. 
 
 When a proportion has but one fub- 
 jecl: and one predicate, it admits of no 
 fubdivifion, and is faid to be fimple. 
 When it has more than one fubjecl:, or 
 more than one predicate \ or has feveral 
 
 fubjeets 
 
( 73 ) 
 
 fubjefts and predicates ; it is faid to be 
 compound. If it have one fubjecl and 
 more than one predicate, — or, vice verfa, 
 one predicate and more than one fubjecl:, 
 — it may, in the one cafe, be refolved 
 into as many fimple proportions as there 
 are predicates, — and, in the other, into 
 as many as there are fubje&s ; as will be 
 obvious from the following examples : 
 The praclice of /wearing in common ccnvcr- 
 fation, is abfurd, unmannerly, and im- 
 pious ; neither kings nor people are exempt 
 from death. Nor is it lefs evident, that 
 if a propofition confifts of feveral fubje&s 
 and predicates, it may be refolved into as 
 many fimple proportions, as there are 
 fubje&s and predicates. Compound pro- 
 portions are of two kinds ; copulative, 
 and disjunctive. A copulative propo- 
 rtion takes place, where the fubjecls and 
 predicates are fo joined together, that 
 K they 
 
( 74 ) 
 
 they may be all feverally affirmed or de- 
 nied of each other. Of this nature are 
 the examples which have been jufl given. 
 A disjunctive proportion compares feveral 
 predicates with the fame fubje£l 9 and af- 
 firms that one of them neceiTarily belongs 
 to it, but without determining which ; 
 as, this world either exists of itfelf or is 
 the work of fome allwife and powerful 
 caufe. It is the nature of all propofitions 
 of this clafs, that, upon determining the 
 particular predicate, the reft are of courfe 
 to be removed ; or, if all the predicates 
 but one be removed, that one neceiTarily 
 takes place : thus, in the example given 
 above, if we allow the world to be the 
 work of fome wife and powerful caufe, 
 we of courfe deny it to be felf-exiftent ; 
 or, if we deny it to be felf-exiflent, we 
 mud neceiTarily admit, that it was pro- 
 duced by fome wife and powerful caufe. 
 
 A pro- 
 
( 75 ) 
 
 A propofition is felf-evident, when, 
 without any invefligation or proof, the 
 truth of it is obvious at firfl view. When 
 we affirm, for inftance, that a fart of 
 any thing is lefs than the whole, or that 
 men exist , and other animals ; whoever 
 underflands the terms made ufe of, per- 
 ceives, at the firfl view, the truth of 
 what is afTerted ; nor can he, by any 
 efforts, bring himfelf to believe the con- 
 trary. A demonftrable propofition is one, 
 ' the truth of which is not immediately 
 perceived by the mind, but may be made 
 to appear by means of other propofitions 
 more known and obvious, whence it fol- 
 lows as an unavoidable confcquence. 
 
 A fpeculative propofition affirms or 
 denies fome property of its fubjecl, as 
 when it is affirmed, that the radii of a 
 circle are all equal. A practical propo 
 fition afferts that fomething may be don- 
 
 o 
 
( 76 ) 
 
 or effected ; as, that a right line may be 
 drawn from one point to another. And 
 from this lafl diftin&ion arifes a four- 
 fold divifion of mathematical proportions, 
 
 into SELF-EVIDENT SPECULATIVE, and 
 SELF-EVIDENT PRACTICAL J DEMON- 
 STRABLE SPECULATIVE, and DEMON- 
 STRABLE practical. Self-evident fpe- 
 culative propofitions are called axioms; 
 and felf-evident practical proportions, 
 postulates : demonftrable fpeculative 
 propofitions, theorems ; and demon- 
 ftrable practical propofitions, problems. 
 
 PART 
 
( 77 ) 
 
 PART III. 
 
 Of Reafoning. 
 
 The fubject of this part of Logick is 
 an extcnfive one; and to difcufs it fully 
 would require much time. We fliall con- 
 tent ourfelves with explaining what is 
 meant by reafoning, and giving fome ac- 
 count of various kinds of fyllogifms, which 
 are ac*ts of reafoning exprefTed in words. 
 To which we fliall fubjoin fuch of the 
 fophifms, or falfe arguments, as are the 
 mofl remarkable. 
 
 CHAP. 
 
( 78 ) 
 
 CHAP. I. 
 
 OfReafoning, and the Parts of which it 
 consists. 
 
 It has been already obferved, that, in 
 comparing two ideas together, it will 
 fometimes happen, that their agreement 
 or difagreement cannot be immediately 
 difcerned. In fuch cafes it becomes ne- 
 ceflary to look out for fome third idea, 
 that will admit of being compared with 
 them, feverally ; that is, firft with one 
 and then with the other : that, by fuch 
 comparifon, we may be enabled to fee, 
 how far the ideas, with which this third 
 is compared, do, themfelves, agree or 
 difagree. For it is a felf-evident truth, 
 
 that, 
 
 f That is, without fome medium* or proof. 
 
 \ 
 
( 79 ) 
 
 Mat, if two things agree with a third, 
 
 hey must agree with each other ; and that, 
 
 'f one of two things agree with a third, 
 
 and the other difagree with it, they must 
 
 difagree with each other. 
 
 From what has been faid, it appears, 
 that every act: of reafoning'necefTarily in- 
 cludes three diftinct judgments : two, 
 in which the ideas, the relations of which 
 we want to difcover, are feverally com- 
 pared with the middle idea ; and a third, 
 in which they are themfelves connected 
 or disjoined, according to the refult of 
 that comparifon. Now, as our judg- 
 ments, when put into words, are called 
 propofitions ; fo our acts of reafoning, 
 when exprefled by words, are termed 
 syllogisms. And hence it follows, that 
 as every act of reafoning implies three 
 feveral judgments, fo every fyllogifm muft 
 include three diftinct propofitions. And 
 
 when 
 
( 8o ) 
 
 when an aft of reafoning is thus put into 
 words, and appears in the form of a fyl- 
 logifm, the intermediate idea made ufe 
 of to difcover the agreement or difagree- 
 ment which we feek to inveftigate, is 
 called the middle term ; and the two 
 ideas themfelves, with which this third 
 is compared, go by the name of ex- 
 tremes. 
 
 But, as thefe things are bed illuftrated 
 by examples, let us fuppofe, that we 
 have fet ourfelves to enquire, whether 
 men are accountable for their aclions. As 
 the relation between the ideas of man 
 and account ablenej s^ comes not within the 
 immediate view of the mind, our firft care 
 muft be, to find out fome third idea that 
 will enable us to difcover and trace it. 
 A very fmall meafure of reflection is fuf- 
 ficient to inform us, that no creature can 
 be accountable for his actions, unlefs we 
 
 fuppofe 
 
( 8i ) 
 
 fuppofe him capable of diftingufthing 
 thofe which are good from thofe which 
 are bad ; that is, unlefs we fuppofe him 
 pofTefled of reafon. Nor is this alone 
 fufficient. For what would it avail him 
 to diftinguiih good from bad actions, if 
 he had no freedom of choice, and could 
 not avoid the one and purfue the other ? 
 Hence it becomes neceffary to take in 
 both thefe coniiderations in the prefent 
 cafe. It is at the fame time equally evi- 
 dent, that wherever there is this ability 
 of diftinguifhing good from bad actions, 
 and purfuing the one and avoiding the 
 other, there alfo a creature is account- 
 able. We have then got a third idea, 
 with which accountabknefs is infeparably 
 connected, namely the idea of a creature 
 f off effed of reafon and liberty. Let us now 
 take this third or middle idea, and com- 
 pare it with the other idea in queition, 
 L namely 
 
( 82 ) 
 
 namely man ; and we all know by expe- 
 rience, that it may be affirmed of him. 
 Having thus, by means of the interme- 
 diate idea, formed two feveral judgments, 
 — that man is poffeffed of reafon and li- 
 berty , and that reafon and liberty imply ac- 
 countablenefs ; a third obvioufly and ne- 
 ceffarily follows, namely that man is ac- 
 countable for his actions . 
 
 Here then we have a complete aft of 
 reafoning, in which, according to what 
 has been already obferved, there are 
 three diftincT: judgments ; two, that may 
 be ftyled previous, in as much as they 
 lc?A to the other, and arife from compar- 
 ing the middle idea with the two ideas in 
 queilion ; and a third, which is a confe- 
 quence of thefe previous acts, and flows 
 from uniting the extreme ideas them- 
 felves. If now we put this reafoning 
 
 into 
 
( §3 ) 
 into due form, it exhibits what Logicians 
 call a fyllogifm, and runs thus. 
 
 Every creature, poffeffed of rcafon and 
 liberty, is accountable for his aclions : 
 
 Man is a creature poffeffed of rcafon and 
 liberty : 
 
 Therefore man is accountable for bis 
 aclions. 
 
 Of thefe three proportions, the two 
 firfl anfwer the two previous judgments, 
 in reafoning ; and are called the pre- 
 mises, becaufe they are placed before the 
 other: the third is termed the con- 
 clusion ; as being gained in confequencc 
 of what was after ted in the premifes. 
 Man and account ablencfs are tile extremes ; 
 and a creature poffeffed of rcafon and li- 
 berty, the middle term. 
 
 We may alfo obferve, that, as the 
 conclufion is made up of the extreme 
 terms of ';.v: fy'lo^ifm, fo that extreme, 
 
 which 
 
( 84 ) 
 
 which ferves as the predicate of the con- 
 clufion, goes by the name of the major 
 term ; and the other extreme, which 
 makes the fubject in the fame proportion, 
 is called the minor term. And again, 
 from this diftindtion between the extremes 
 arifes alfo a diftin&ion between the pre- 
 mifes ; where thefe extremes are feverally 
 compared with the middle term : that 
 propofition which compares the major 
 term, or the predicate of the conclufion, 
 with the middle term, being called the 
 major proposition ; the other, where- 
 in the fame middle term is compared with 
 the fubjecl: of the conclufion or minor 
 term, being called the minor propo- 
 sition. To which may be added, that, 
 when a fyllogifm is propofed in due form, 
 the major propofition is always placed 
 firft, the minor next, and the conclufion 
 
 M. 
 
 Thefe 
 
C 8 5 ) 
 
 Thefe things premifed, we may* define 
 reafoning to be, an acl or operation of the 
 mind, deducing fame propq/ition, the truth of 
 which was before unknown, from other pre- 
 vious ones that are either felf evident orfuch 
 as have been fully proved and establiJJjed. 
 Thefe previous proportions, in a fimple 
 aft of reafoning, are only two in number; 
 and, in order to afford an unqueflionable 
 conclufion, muft be intuitive propofitions. 
 When they are not fo, . previous fyllo- 
 gifms are required : in which cafe reafon- 
 ing becomes a complicated acl:, taking 
 in a variety of fucceffive fteps. If, for 
 example, in the major of the fyllogifm 
 given above, viz. Every creature poffeffed 
 of re af on and liberty is accountable for his 
 aclions, the connexion between the fub- 
 ject and predicate could not be perceived 
 by the mere attention of the mind to the 
 ideas themfelves, it is evident that this 
 
 propofition 
 
( 86 ) 
 
 propofition would no lefs require proof 
 than the conclufion deduced from it. In 
 this cafe, a new middle term mud be 
 fought for, to" trace the connexion here 
 fuppofed ; and this, of courfe, furnifhes 
 another fyllogifm ; by which having efta- 
 blifhed the propofition in queftion, we 
 are then, and not before, at liberty to 
 ufe it in any fucceedin'g act of reafoning. 
 And mould it fo happen, that, in the 
 fecond fyllogifm, there were ftill fome 
 previous propofition, the truth of which 
 did not appear at firft fight, we mud 
 then have recourfe to a third fyllogifm, 
 in order to lay open that truth to the 
 mind ; becaufe, fo long as the premifes 
 remain uncertain, the conclufion, built 
 upon them, rauft be fo too. And when, 
 by conducting our thoughts in this man- 
 ner, we at laft arrive at fome fyllogifm 
 where the previous propofitidns are in- 
 tuitive 
 
( 87 ) 
 
 tuitive truths, the mind then refts in full 
 fecurity ; as perceiving, that the feveral 
 conclufions, which it has palTed through, 
 fland upon the immoveable foundation of 
 felf-evidence, and, when traced to their 
 fource, terminate in it. 
 
 And here, if, after having thus un- 
 ravelled a demonstration, we take it the 
 contrary way, and obferve how the mind, 
 fetting out with intuitive proportions, 
 connects them together to form a con- 
 clufion ; how, by introducing this con- 
 clufion into another fyllogifm, it Mill ad- 
 vances one ftep farther ; and fo proceeds, 
 making every new difcoveryfubfervient 
 to future progrefs ; we (hall then perceive 
 clearly, that reafoning, in the higheft 
 exercife of that faculty, is no more than 
 an orderly combination of thofe fimple 
 acts which we have already fo fully ex- 
 plained. And we fhall alfo perceive, 
 
 that 
 
( 83 ) 
 
 that all the knowledge acquired by rea- 
 foning, how far foever we may carry our 
 difcoveries, is (till built upon our intuitive 
 judgments ; every difcovery of human 
 reafoning being the confequence of a fyl- 
 logifm, the premifes of which are felf- 
 evident proportions, — or of a train of 
 fyllogifms, which, when traced to their 
 fource, always terminate in them. 
 
 fa^str ecs£^&<+^^ H A R IL 
 
 Of Syllogifms. 
 
 Syllogisms may be divided into 
 single and compound. Single fyllo- 
 gifms are thofe which confifl of three pro- 
 portions, and no more. Compound fyl- 
 logifms are thofe which confifl of more 
 
 than 
 
< 89 ) 
 than three proportions, and may be form- 
 cd into two or more fyllogifms. 
 
 Of [ingle Syllogifms. 
 
 Single fyllogifms may be divided into 
 feveral forts ; of which the mod import- 
 ant are simple or categorical, con- 
 ditional, and disjunctive. 
 
 Thofe are properly called Simple, or 
 Categorical, fyllogifms, which are made 
 \ip of three plain, fimple, or categorical 
 proportions ; in which the middle term is 
 joined with one part of the queflion in 
 the major proportion, and with the other 
 in the minor. 
 
 And here, to guard us againfl falfe in- 
 ferences, certain rules have been found 
 neceffary, which depend on the four fol- 
 lowing axioms. 
 
 i. Particular proportions are contain- 
 ed in univerfais, and may be inferred 
 M frcm 
 
( 9° ) 
 from them ; but univerfals are not con- 
 tained in particulars, and cannot be in- 
 ferred from them. 
 
 2. In all univerfal propofitions, the 
 fubjecl: is univerfal : in all particular pro- 
 pofitions, the fubjecT: is particular. 
 
 3. In all affirmative propofitions, the 
 predicate has no greater extenfion than 
 the fubjecT: ; for its extenfion is retrained 
 by the fubjecT: : and therefore it is always 
 to be efteemed as a particular idea. It 
 is by mere accident, if ever it be taken 
 univerfally ; and cannot happen, but in 
 fuch univerfal or fmguiar propofitions as 
 are reciprocal.! 
 
 4. The predicate of a negative propo- 
 rtion is always taken univerfally ; for, 
 in its whole extenfion, it is denied of 
 
 the 
 
 j- A proportion is faid to be reciprocal, when the 
 fubject and the predicate may mutually inter- 
 change their places with prefervation of the truth. 
 
C 9* ) 
 
 the fubjecl:. If we fay, no stone is vege- 
 table, we deny all forts of vegetation con- 
 cerning flones. 
 
 The rules are thefe. 
 
 1. The middle term must not be taken 
 twice particularly, but once at least uni- 
 verfally. For if the middle term be taken 
 for two different parts or kinds of the 
 fame univerfal idea, then the fubjefl: of 
 the conclufion, or minor extreme, is com- 
 pared with one of thefe parts, and the 
 predicate, or major extreme, with the 
 other part, and this will never fhow whe- 
 ther that fubjecl: and predicate agree or 
 difagree ; for there will then be four 
 diftincl: terms in the fyllogifm, and the 
 two parts of the queftion, that is the two 
 extremes, will not be compared with the 
 fame third idea. 
 
 2. The terms, in the ccnclufion, must 
 never be taken more univerfally than they 
 
 are 
 
( 9* ) 
 
 are in the premifes. The reafon is deriv- 
 ed from the firfl axiom, that generals can 
 never be inferred from particulars. 
 
 3. A negative conclufion cannot be prov- 
 ed by two affirmative premifes. For, when 
 the two terms of the conclufion are unit- 
 ed or agree with the middle term, it does 
 not by any means follow that they difagree 
 with one another. 
 
 4. If one of the premifes be negative ', the 
 conclufion must be negative. For if the 
 middle term be denied of either part of 
 the conclufion, it may mow that the 
 terms of the conclufion difagree, but it 
 can never mow that they agree. 
 
 5. If either of the premifes be particular ■, 
 the conclufion must be particular. This 
 may be proved from the firft axiom. 
 Thefe two lafl rules are fometimes united 
 in this fmgle fentence, the conclufion al- 
 ways follows the weaker part of the premifes* 
 
 For 
 
( 93 ) 
 
 For negatives and particulars are account- 
 ed inferior to affirmatives and univerfals. 
 
 6. From two negative premifes, nothing 
 can be concluded. For they feparate the 
 middle term both from the fubjec~t and the 
 predicate of the conclufion ; and when 
 two ideas difagree with a third, we can- 
 not infer that they either agree or dif- 
 agree with each other. 
 
 7. From two particular premifes, nothing 
 can be concluded. This rule depends chiefly 
 on the firft axiom. 
 
 In forming fyllogifms, efpecially thofe 
 of which we are now treating, we make 
 ufe of figure sand moods. By the Figure 
 of a fyllogifm, is meant the peculiar way 
 in which the middle term is connected 
 with the extremes. By the Moods be- 
 longing to a figure, are meant, the feve- 
 ral ways in which the proportions of one 
 fyllogifm may differ from thofe of another, 
 
 belonging 
 
( 94 ) 
 
 belonging to the fame figure, as to quan- 
 tity and quality; that is, as to their 
 being univerfal or particular, affirmative 
 or negative. 
 
 Figures are ufually reckoned three. 
 In thcjirst, the middle term is the fubjeft 
 of the major, and the predicate of the 
 minor, proportion. In the fecond^ it is 
 the predicate of both thefe propofitions ; 
 and, in the thirds the fubjeft. And that 
 this account of the figures might be the 
 better remembered, it has been expreffed 
 as follows : Sub prce, primse ; bis pra, 
 fecunda?; tertise, bis fub. 
 
 The moods, belonging to each of thefe 
 figures, are fignified by certain artificial 
 words, in which the confonants are ne- 
 glected, and the vowels only regarded ; 
 <z, denoting, as was before obferved, an 
 univerfal affirmative; e, an univerfal ne- 
 gative ; L a particular affirmative ; and 
 
 0, a 
 
( 95 ) 
 
 <?, a particular negative. And, to afTift 
 the memory in retaining thefe words, 
 they are comprifed in four iaiin verfes. 
 
 Barbara, Celarentj Darii, Ferio quoque, 
 
 prima?. 
 Cefare, Camestres, Festino, Baroco, fecunda?. 
 Tertia Darapti fibi vindicat atque Felapton, 
 Adjungens Difamis, Datifi 9 Bocardo, Fe- 
 
 rifon* 
 
 Bar- All wicked men are miferable : 
 ba- Tyrants are wicked men : 
 ra. Therefore tyrants are mifer- 
 able. 
 
 Ce- They who are always in fear 
 
 cannot be happy : 
 la- Covetous men are always in 
 
 fear : 
 rent. Therefore covetous men cannot 
 
 be happy. 
 
 Da. 
 
( 96 ) 
 
 Da- Whatfoever furthers our falvation 
 is good for us : 
 
 ri- Some afflictions further our fal- 
 vation : 
 
 i. Therefore fome afflictions are 
 good for us. 
 
 Fe- Nothing that must be repented of is 
 
 defirable : 
 
 ri- Sinful pleafures must be repented 
 of: 
 
 o. Therefore finful pleafures are not 
 
 defirable. 
 
 It is the excellence of this figure, that 
 all queftions may be proved by it, whe- 
 ther univerfal or particular, affirmative or 
 negative. 
 
 In the fecond figure alfo, there are four 
 
 moods -, but it admits of negative con- 
 
 clufions only. 
 
 Ce- 
 
C 97 ) 
 
 Ce- No praftice can be innocent, 
 which is inconsistent with the 
 Christian law of Charity ; f 
 
 sa- The praftice of reducing men, of 
 any colour, to a ftate of flavery, 
 is inconsistent with the Christian 
 law of Charity : 
 
 re. Therefore the practice of reducing 
 men, of any colour, to a ftate 
 of flavery, cannot be innocent. 
 
 Ca- Every man of ft rift honour 
 would difdain to enrich himfilf 
 at his neighbour's expenfe : 
 
 mes- No gamefter difdains to enrich 
 himfelf at his neighbour's ex- 
 penfe : 
 
 tres. Therefore, no gamefter is a 
 man of ftrift honour. 
 
 N Fes- 
 
 f " Whatsoever ye would that men ihould do to 
 you, do ye even fo to them." Matt, vii 12. 
 
( 98 ) 
 
 Fes- No' fins are excufable : 
 
 tu Anger, upon fome occafions, is 
 excufable : 
 
 no. Therefore anger, upon fome oc- 
 cafions, is not a fin. 
 
 Ba- Every true patriot will feek to 
 promote peace and concord among 
 . his fellow citizens : 
 
 ro. Some who profefs to be patriots 
 do not feek to promote concord 
 and peace among their fellow 
 citizens : 
 
 co. Therefore fome who profefs to be 
 -patriots, are not true patriots. 
 
 In the third figure there are fix moods ; 
 and the conclufion is always particular. 
 
 Da- All good christians fliall be faved : 
 
 rap- All good christians have finned : 
 
 ti. Therefore fome that have finned 
 
 fhall be faved. 
 
 Fe- 
 
( 99 ) 
 
 Fi- No hypocrites are pleafing to 
 God. 
 
 lap- All hypocrites feem to be reli- 
 gious : 
 
 Ton. Therefore fome who feem to be 
 religious are not pleafing to 
 God. 
 
 Di- Some felfifo and turbulent men y 
 make very violent prctenfions 
 to patriotifm : 
 
 sa- All felfijh and turbulent men arc 
 deftitute of any real love for 
 their country : 
 
 mis. Therefore fome who arc deftitute 
 of any real love for their coun- 
 try, make very violent prcten- 
 fions to patriotifm. 
 
 Da- 
 
( ™° ) 
 
 Da- All honest men are entitled to our 
 love and efleem : 
 
 ti- Some honest men differ very wide- 
 ly from us in their fentiments 
 on religion and politicks : 
 
 si. Therefore fome, who differ very 
 widely from us in their fenti- 
 ments on religion and- poli- 
 ticks, are entitled to our love 
 and efteem. 
 
 Bo- Some wars are not to be a- 
 
 voided : 
 car- All wars produce blood-fhed : 
 
 do. Therefore fome blood-fhed is not 
 to be avoided. 
 
 Fk- No affiicllons are pleafant : 
 ri- Some dffliclions are good for us : 
 son. Therefore fome things that are 
 good for us are not pleafant. 
 
 The 
 
( ioi ) 
 
 The fpecial rules of the three figures 
 are thefe. In the firft, the major propo- 
 rtion must always be univerfal, and the 
 minor affirmative. In the fecond, the ma- 
 jor must alfo be vniverfal, and one of the 
 premifes, together with the conclufion, must 
 be negative. In the third, the minor must 
 be affirmative, and the conclufion always 
 particular. 
 
 There is alfo a fourth ; in which the 
 middle term is the predicate of the major 
 proportion, and the fubject of the minor. 
 But this, being a very indirect and ob- 
 lique manner of concluding, is never ufed 
 in the fciences, or in common life ; and 
 is, confequently, ufelefs. 
 
 A Conditional or Hypothetical fyl- 
 logifm is a fyllogifm of which the major 
 is a conditional or hypothetical propo- 
 fition ; as 
 
 v 
 
( 102 ) 
 
 If there be a God he ought to be worfhip- 
 ped: 
 
 But there is a God : 
 
 Therefore he ought to be worfhipped. 
 
 And here it is to be obferved, that, in 
 all propofitions of this kind, the antece- 
 dent mud always contain fome certain 
 and genuine condition, which neceffarily 
 implies the confequent ; for otherwife the 
 propofition itfelf will be falfe, and there- 
 fore ought not to be admitted into our 
 reafonings. Hence it follows, that, when 
 any conditional propofition is affumed, if 
 we admit the antecedent of that propo- 
 fition, we mull at the fame time neceffarily 
 admit the confequent ; but if we reject 
 the confequent, we mutt in like manner 
 neceifarily reject the antecedent. It ap- 
 pears then, that, in conditional fyllo- 
 gifms, there are two ways of arguing 
 which lead to a certain and unavoidable 
 
 conclufion. 
 
C *°3 ) 
 
 concluflon. i. From the admijfion of the 
 antecedent, to the admijfion of the confc- 
 quent : which conftitutes the mood or 
 fpecies of hypothetical fyllogifms, diftin- 
 guifhed in the fchools by the name of the 
 modus ponens ; in as much as by it 
 the whole conditional proportion is esta- 
 blijhed. And, of this mood, the fyllo- 
 gifm given above is an example. 2. From 
 the removal of the confequent to the removal 
 of the antecedent : which conftitutes the 
 mood or fpecies called by Logicians the 
 modus tollens, becaufe by it both an- 
 tecedent and confequent are rcjccled ; as 
 appears by the following example. 
 
 If the fun be rifen, the night is past : 
 
 But the night is not past : 
 
 Therefore the fun is not rifen. 
 
 Thefe two fpecies take in the whole 
 clafs of conditional fyllogifms, and include 
 all the poffible ways of arguing that lead 
 
 by 
 
( *04 ) 
 
 by them to a legitimate conclufion ; be- 
 caufe we cannot here proceed by a con- 
 trary procefs of reafoning, that is, from 
 the removal of the antecedent to the re- 
 moval of the confequent, or from the 
 eftablifhing of the confequent to the efta- 
 blifhing of the antecedent. For although 
 the antecedent always exprefTes fome real 
 condition, which, once admitted, necef- 
 farily implies the confequent, yet it does 
 not follow that there is therefore no other 
 condition ; and if fo, then, after remov- 
 ing the antecedent, the confequent may 
 flill hold, becaufe of fome other con- 
 dition which implies it. When we fay, 
 If a stone be expofedfor some time to the rays 
 of the fun i it will contra cl a degree of heat ; 
 the proportion is certainly true, and, ad- 
 mitting the antecedent, we mud admit 
 the confequent. But as there are other 
 ways by which a (tone may contract a de- 
 gree 
 
( '°5 ) 
 
 gree of heat, it will not follow, from 
 the abfence of the before mentioned con- 
 dition, that therefore the confequent can- 
 not take place. In other words, we can- 
 not argue, But this stone has not been ex- 
 pofed to the rays of the fun ; therefore it has 
 not eontracled a degree of heat ; in as much 
 as there are other ways, by which heat 
 might have been contracted by it. — And 
 as we cannot argue from the removal of 
 the antecedent to the removal of the con- 
 fequent, no more can we argue from the 
 admifTion of the confequent to the ad- 
 mhTion of the antecedent. Becaufe as 
 the confequent may flow from a variety 
 of caufes, the allowing of it does not de- 
 termine the precife caufe, but only that 
 there mufl have been fome one of them. 
 Thus, in the foregoing propofition, If a 
 stone be expofed for fome time to the rays of 
 thefun, it will contracl a degree of heat , — 
 O admitting 
 
( Jo6 ) 
 
 admitting the confequent, namely that it 
 has contracted a degree of heat, we are 
 not therefore bound to admit the ante- 
 cedent, that it has for fome time been ex- 
 pofed to the rays of the fun ; in as much as ' 
 there are other caufes whence that heat 
 may have proceeded. — Thefe two ways 
 therefore of arguing, hold not in con- 
 ditional fyllogifms : except indeed, where 
 the antecedent exprefles the only condi- 
 tion ; which is a cafe that happens but 
 feldom, and cannot be extended to a ge- 
 neral rule. 
 
 A Disjunctive fyllogifm is a fyllogifm 
 of which the major is a disjunctive pro- 
 portion ; as in the following example. 
 
 The world is either felf existent, or the 
 work of y ome finite, or of fome infinite being i 
 
 But it is not fef -existent, or the work of 
 , a finite being : 
 
 Therefore it is the work of an infinite being. 
 A Now 
 
< ic 7 ) 
 Now a disjunctive Proportion is that, 
 in which, of feveral predicates, we affirm 
 one neceflarily ro belong to the fubject, 
 to the exclufion of all the reft ; but leave 
 that particular one undetermined.- Hence 
 it follows, that as foon as we determine 
 the particular predicate, all the reft are 
 of courfe to be" rejected ; or if we reject 
 all the predicates but one, that one nc- 
 ceflarily takes place. When therefore, 
 in a disjunctive Syllogifm, the feveral pre- 
 dicates are enumerated in the major, if 
 the minor eftabliflies any one of thefe 
 predicates, the conclufion ought to re- 
 move all the reft ; or if, in the minor, all 
 the predicates but one are removed, tiie 
 conclufion muft neceflarily eftablifh that 
 one. Thus, in the disjunctive fyllogifm 
 given above, the major affirms one of 
 three predicates to belong to the earth \ 
 namely, that it is felf-exis lent, or that it is 
 
 the 
 
( io8 ) 
 
 the work of *a finite, or that it is the work of 
 an infinite being: two of thefe predicates are 
 removed in the minor ; nzmdyfelf -exist- 
 ence, and the work of a finite being : hence 
 the conclufion neceffarily afcribes to it the 
 third predicate, and affirms that it is the 
 work of an infinite being. If now we give 
 the fyllogifm another turn, fo that the 
 minor may establifh one of the predi- 
 cates, by affirming the Earth to be the 
 production of an infinite being; then the 
 conclufion muft remove the other two ; 
 by affirming it to be neither felf-exist- 
 ent, nor the work of a finite being. Thefe 
 are the forms of reafoning in this fpecies 
 of fyllogifms ; the juftnefs of which ap- 
 pears at firfl fight : and that there can 
 be no other, is evident from the very na- 
 ture of a disjunctive proportion. 
 
 Of 
 
( *°9 ) 
 
 Of Compound Syllogifms. 
 
 A compound fyllogifm, confifts, as was 
 before obferved, of more than three pro- 
 portions, and may be refolved into two 
 or more fyllogifms. The chief of thefe 
 are the Epichirema, Dilemma, Pro- 
 syllogism, Sorites, and Induction 
 of particulars. 
 
 Epichirema is a fyllogifm, in which we 
 prove the major, or the minor, or both, 
 before we draw the conclufion. As, 
 
 Sicknefs may be good for us ; becaufe it 
 brings us to confidcr our ways : 
 
 But we are- uneafy under ficknefs ; as 
 appears from cur fighs, groans, and com- 
 plaints : 
 
 Therefore we are fometimes uneafy under 
 what is good for us, 
 
 A Dilemma is an argument, by which 
 we endeavour to prove the abfurdity or 
 
 falfehood 
 
I no ) 
 
 falfehood of fome alTcrtion. In order to 
 this, we affume a conditional proportion, 
 the antecedent of which is the afTertion 
 to be difprotfed, and the confequent a 
 disjunctive proportion, enumerating all 
 the poflible fuppofitions upon which that 
 afTertion can take place. If then it appear, 
 that all thefe fuppofitions ought to be re- 
 jected, it is plain that the antecedent or 
 afTertion itfelf mud be rejected alfo. 
 When, therefore, fuch a proportion is 
 made the major of any fyllogifm, if the 
 minor rejects all the fuppofitions contain- 
 ed in the confequent, it follows necef- 
 farily, that the conclufion mufl reject the 
 antecedent ; which, as has been faid, is 
 the afTertion to be difproved. Hence it 
 appears, that we may define a dilemma 
 to be a conditional or hypothetical fyllo- 
 gifm, where the confequent of the major 
 is a disjunctive proportion, which is 
 
 wholly 
 
( III ) 
 
 wholly taken away or removed in the 
 minor. It follows, that a dilemma is an 
 argument in the modus to/lens of condi- 
 tional fyllogifms. And it is plain, that, 
 if the antecedent of the major be an affir- 
 mative propofition, the conclufion will be 
 negative ; but if it be a negative propo- 
 fition, the conclufion will be affirmative. 
 
 The following is an example. 
 
 If God did not create the world perfcel 
 in its kind ; it must have proceeded, either 
 from want of inclination, or want of power : 
 
 But it could not have proceeded, either 
 from want of inclination, or want of power : 
 
 Therefore it is abfurd to fay, that God 
 did not create the world perf eel in its kind. 
 
 A dilemma may be faulty three ways. 
 i. When what is affirmed or denied, in 
 the minor, concerning the feveral fuppo- 
 fitions in the confequent of the major, is 
 falfe. 2. When all the poffible fuppo- 
 
 fitiens 
 
( M» ) 
 
 fitjons upon which the affertion, contain- 
 ed in the antecedent, can take place, are 
 not fully enumerated in the confequent. 
 3. When the argument may be retorted 
 with equal force againfl: him who ufes it. 
 
 A Profyllogifm is a form of reafoning, 
 in which two or more fyllogifms are fo 
 connected together, that the conclufion 
 of the former is the major or minor of the 
 following. 
 
 Blood cannot think : 
 
 But the foul of man thinks : 
 
 Therefore the foul of?nan is not blood. 
 
 The foul of a brute is blood : 
 
 Therefore the foul of man is different from 
 the foul of a brute, 
 
 A Sorites is a way of arguing, in which 
 feveral proportions are fo linked together 
 that the predicate of one becomes con- 
 tinually the fubjecl of the next following ; 
 until at laft a conclufion is formed, by 
 
 bringing 
 
( "3 J 
 
 bringing together the fubject of the firft 
 proportion, and the predicate of the laft -, 
 as in the following example. 
 
 There can be no enjoyment of -property , 
 
 without government : 
 
 No government, without a magistrate : 
 
 No magistrate, without obedience : 
 
 And no obedience where every one acls 
 
 as he pleafes : 
 
 Therefore there can be no enjoyment of 
 
 property, where every one acls as he pleafes. 
 
 Reafoning by Induction is, when we 
 infer univerfally concerning any idea, 
 what we have before affirmed or denied 
 feparately, of all its feveral parts or fub- 
 divifions. Thus if we fuppofe the whole 
 race of animals fubdivided into men, 
 beads, birds, infects, and fifhcs, and then 
 reafon concerning them in this manner, — 
 All me\i have the power of beginning motion ; 
 P all 
 
( "4 ) 
 
 all beasts have this power ; all birds ; all 
 infecls ; all Jijhes : therefore all animals 
 have the -power of beginning motion ; — the 
 argument is an Indu&ion. The truth of 
 the conclufion, in this way of reafoning, 
 depends upon the parts and fubdivifions 
 being fully enumerated. 
 
 Laftly, in reafoning, efpecially where 
 it makes a part of common converfation, 
 we ufe a fort of Elliptical fyllogifms called 
 enthymemes, confiding of the conclu- 
 fion and one of the premifes ; the other, 
 which, in thefe cafes, is not only an evi- 
 dent truth, but alfo familiar to the minds 
 of all men, being fuppreffed. As, for 
 example, 
 
 Every man is mortal : 
 Therefore every king is mortal : 
 
 God is our creator : 
 
 Therefore he must be worfhipped* 
 
 Thefe 
 

 t "5 ) 
 
 Thefe fyllogifms appear to be imper- 
 fect, as confiding each of but two propo- 
 rtions : yet are they, in reality, com- 
 plete ; except that, in the firfl, the minor, 
 every king is a man, — and, in the fecond, 
 the major, our creator is to be worfhipped^ 
 — are omitted, and left to the reader to 
 fupply, — as a proportion fo evident, and 
 at the fame time fo familiar, that it can- 
 not efcape him. But thefe belong to the 
 head of fingle fyllogifms. 
 
 To this chapter, which treats of various 
 kinds of fyllogifms, it may not be impro- 
 per to add fome account of feveral forts 
 of arguments, which are ufually diflin- 
 guifhed by Latin names. For as thefe 
 names will occafionally occur, in books 
 
 and 
 
f 116 ) 
 
 and in converfation, it will be of ufe to 
 underfland what is meant by them. 
 
 Demonflrations a priori are thofe 
 which prove the effect from the caufe : 
 as, The fcripture is infallible ; becaufe it is 
 the word of God who cannot lie. Demon- 
 ftrations a posteriori, on the contrary, 
 are thofe which prove the caufe from the 
 effect : as, All the works of God are ufeful 
 and well contrived : therefore the Creator 
 is wife and good. 
 
 The ARGUMENTUM DUCENS IN AB- 
 
 surdum has been already explained. 
 We mall only add that it is fometimes 
 called reductio ad absurdum, and a 
 
 proof PER IMPOSSIBILE. 
 
 ' When we infer, that a certain propo- 
 rtion is true, becaufe another has been 
 proved to be true which is lefs probable, 
 this is. called an argument ex minus 
 
 PROBABILI AD MAGIS. 
 
 When 
 
( U 7 ) 
 
 When we argue from the certainty of 
 a thing in the fame circumftances, we are 
 faid to argue ex pari. 
 
 When we prove the truth of any pro- 
 portion, upon which, if proyed, our op- 
 ponent had agreed to admit the truth of 
 the propofition in queftion, this is an ar- 
 gument EX CONCESSO. 
 
 When an argument is taken from the 
 nature of things and addreffed to the rea- 
 fon of mankind, it is called argumentum 
 
 ad JUDICIUM. 
 
 When it is borrowed from fome con- 
 vincing tcflimony, it is argumentum 
 
 AD PIDEM. 
 
 When it is drawn from any infufficient 
 medium whatfoever, in confidence that 
 our oppofer has not Ikill to refute or an* 
 fwer it, this is argumentum ad igno- 
 
 RANTIAM. 
 
 When 
 
( "8 ) 
 
 When we prove a thing to be true, or 
 falfe, from the profefTed opinion of the 
 perfon with whom we difpute, it is named 
 
 ARGUMENTUM AD HOMINEM. 
 
 When the argument is brought from 
 the fentiments of fome wife, grave, or 
 good men, whofe authority we reverence 
 and hardly dare oppofe, it is called ar- 
 
 GUMENTUM AD VERECUNDIAM, Or AD 
 MODESTIAM. 
 
 When we expofe a man to hatred by 
 alleging that his opinion has been held 
 by fome hereticks or wicked men, calling 
 him a Socinian, a Jacobin, or the like, 
 
 it is ARGUMENTUM AB INVIDIA DE- 
 DUCTUM. « 
 
 And, laflly, when an argument is bor- 
 rowed from any topicks which are fuited 
 to engage the inclinations or paffions of 
 the hearers on the fide of the fpeaker, 
 rather than to convince their judgments, 
 
 this 
 
( "9 ) 
 
 this 1S ARGUMENTUM AD PASSIONES, Or 
 
 if it be made publickly, ad populum. 
 
 CHAP. III. 
 
 Of Sophifms, 
 
 Sophisms are falfe arguments that 
 have the appearance of being true. 
 
 The mod remarkable of them are re- 
 duced by Logicians to the following 
 heads. 
 
 i. Ignorantia elenchi, or a mif- 
 take of the queftion. As if, the queftion 
 being put, whether excefs of wine be hurt- 
 ful to thofe who indulge in it, any one 
 mould argue, that wine revives the fpirits, 
 gives a man courage, and makes him 
 more flrong and a&ive ; and then take 
 it for granted, that the point in debate 
 
 is 
 
C I2 ° ) 
 
 is fully determined. But what, it mig^ht 
 be anfwered, is all this to the purpofe ? 
 Wine, drank in moderation, may have 
 all thefe good effects which you afcribe 
 to it ; but the queflion is not, what are 
 the effects of wine drank in moderation, 
 but what are the effects of it when drank 
 to excefs. 
 
 2. Petitio principii, or a fuppo- 
 fition of what is not granted ; as, 
 
 There is nofahation out of the church : 
 Protestants are out of the church : 
 Therefore , Protestants cannot be five d. 
 
 The minor is here taken for granted, 
 which is by no means to be allowed. 
 
 3. A circle is, when we prove one 
 of the premifes by the conclufion, and the 
 conclufion by the premifes. 
 
 As if one were to reafon thus : 
 
 The 
 
( 12' ) 
 
 The church being infallible, what Jhe 
 testifies must be believed : 
 
 But the church testifies, that the fcrip- 
 tures are the word of God. 
 
 Therefore, that the fcriptures are the 
 Word of God, must be believed. 
 — and on being afked how it appears 
 that the church is infallible, fhould un- 
 dertake to prove it, as follows : 
 
 What the fcriptures teach us, is not to be 
 questioned : 
 
 But the fcriptures teach us, that the 
 church is infallible : 
 
 Therefore the infallibility of the church 
 is not to be questioned. 
 
 In this way we might prove any thing. 
 
 4. Non causa pro causa, or the 
 affignation of a falfe caufe : as if any one, 
 when an infectious difeafe is imported into 
 a city, fhould impute the misfortune to 
 the anger of God. 
 
 Q 5. Fal- 
 
( 122 ) 
 
 5* FalIvAcia accidentis ; when we 
 argue from what is true by accident, to 
 what is true in the nature of things. So 
 if opium, or the peruvian bark, has been 
 ufed imprudently, or unfuccefsfully, fo 
 as to do injury ; fome abfolutely pro- 
 nounce againit the ufe of the bark, or of 
 opium, on all occafions, and are ready to 
 call them poifons. 
 
 6. The next fophifm borders on the 
 former ; and is, when we argue from 
 that which is true in particular circum- 
 flances, to prove the fame thing true ab- 
 folutely and abftracledly from all circum- 
 ilances : this is called, in the fchools, a 
 
 fophifm A DICTO SECUNDUM QUID, AD 
 DICTUM SIMPLICITER ; as, 
 
 That which is bought in the fhambles is 
 eaten for dinner : 
 
 Raw meat is bought in the (hambles : 
 Therefore raw meat is eaten for dinner. 
 
 This 
 
( «*3 ) 
 This fort of fophifm has its reverfc, 
 when we argue a dicto simpliciter 
 
 AD DICTUM SECUNDUM QUID; 01", tO 
 
 exprefs it in Englifh, from that which is 
 true fimply and abfolutely, to prove the 
 fame thing true in all particular circum- 
 flances : as if a traitor mould arpue from 
 
 o 
 
 the fixth commandment, Thou [halt not 
 kill, to prove that he himfelf ought not 
 to be hanged. 
 
 7. There are alfo fophifms of com- 
 position and division. 
 
 A fophifm of compofition is, when 
 we infer any thing concerning ideas in x 
 compounded fenfe, which is only true In 
 a divided fenfe ; as, 
 
 Christ made the blind to fee, and the deaf 
 to hear : 
 
 Therefore he performed contradicliom. 
 
 Two and three are even arid odd : 
 Five are two and three : 
 Therefore five is even and odd. 
 
 A 
 
( 124 ) 
 
 A fophifm of divifion is, when wre 
 infer the fame thing concerning ideas in 
 a divided fenfe, which is only true in a 
 compound fenfe. As, 
 
 Five is one number : 
 
 Two and three are Jive : 
 
 Therefore two and three are one number. 
 
 Lafliy, Sophifms arife alfo from the 
 ambiguity of words ; and indeed feveral 
 of the former fallacies might be reduced 
 to this head. As if one fliould argue 
 thus, 
 
 A church is a building of stone : 
 
 A religious affembly is a church : 
 
 Therefore a religious affembly is a build- 
 ing of stone. 
 
 Befides the fpecial defcription of true 
 fyllogifms and fophifms already given, 
 and the rules by which the one are form- 
 ed 
 
( "5 ) 
 
 cd and the other refuted ; there are thefe 
 two general methods of reducing all fyl- 
 logifms whatever to a ted of their truth 
 or falfehood. 
 
 i . One of the premifes must contain the 
 conclufion ^ and the other must Jhew that the 
 conclufion is contained in it. 
 
 For the illuftration of this, let us take 
 the following example : 
 
 Whofoever is a Jlave to his natural in- 
 clinations is miferable : 
 
 A wicked man is a Jlave to his natural 
 inclinations : 
 
 Therefore a wicked man is miferable. 
 
 Here it is evident, that the major pro- 
 portion contains the conclufion ; for, 
 under the general character of a Jlave to 
 natural inclinations ', a wicked man is con- 
 tained or included ; and the minor propo- 
 rtion declares it : whence a conclufion is 
 
 evidently 
 
( "« ) 
 
 evidently deduced that the wicked man is 
 miferable. 
 
 2. As the terms in every fyllogifm dre 
 ufually repeated twice ^fo they must be taken 
 precifely in the fame fenfe in both places. 
 
 For the greater part of the miftakes, 
 which arife in forming fyllogifms, is de- 
 rived from fome little difference in the 
 fenfe of one of the terms in the two parts 
 of the fyllogifm wherein it is ufed. • 
 
 // is a fin to kill a man : 
 
 A murderer is a man : 
 
 Therefore it is a fin to kill a murderer* 
 
 Here the word kill in the firfh propo- 
 rtion fignifies to kill unjuftiy, or without 
 a law ; in the conclufion, it is taken ab- 
 folutely for putting a man to death in 
 general ; and therefore the inference is 
 not good. 
 
 What I am is a man : 
 
 Tou are not what I am : 
 
 Therefore you are not a man* 
 
 Here 
 
( **7 ) 
 
 Here what I am in the major propo- 
 rtion, is taken fpecially, for my nature ; 
 but, in the minor propofition, the fame 
 words are taken individually, for my 
 per/on : therefore the inference mufl be 
 falfe ; for the fyllogifm does not take the 
 term what I am both times in the fame 
 fenfe. 
 
 He who fays, you are an animal \ fays 
 true : 
 
 But he who fays, you are a goofe, fays, 
 you are an animal : 
 
 Therefore he who fays, you are a goofe, 
 fays true. 
 
 In the major propofition the word 
 'animal is the predicate of an incidental 
 propofition ; which incidental propofition 
 being affirmative renders the predicate of 
 it particular, according to the third axiom. 
 And confequently the word animal there, 
 fignifies only human animality. In the 
 
 minor 
 
( "8 ) 
 
 minor propofition the word animal for the 
 fame reafon fignifies the animality of a 
 goofe ; therefore it becomes an ambigu- 
 ous term, and unfit to build a conclufion 
 upon. 
 
 PART IV. 
 
 Of Method. 
 
 We have now done with the three 
 firfl operations of the mind. There is 
 yet a fourth ; which regards the difpofal 
 and arrangement of our thoughts in fuch 
 a manner as that their mutual connection 
 and dependence may be clearly feen ; and 
 this is what Logicians call method. 
 
 In unfolding any part of human know- 
 ledge, the relations of things do not al- 
 ways 
 
C I2 9 ) 
 
 ways immediately appear, upon compar- 
 ing them with one another. Hence we 
 have recourfe to intermediate ideas, and 
 by means of them are furnifhed with 
 thofe previous propofitions that lead to 
 the conclufion we are in quefl of. And 
 if it fo happen, that the previous propo- 
 fitions themfelves are not fufficiently evi- 
 dent, we endeavour by new middle terms 
 to afcertain their truth ; ftill tracing things 
 backward, in a continued feries, until at 
 length we arrive at fome fyllogifm where 
 the premifes are firft and felf-evident prin- 
 ciples. This done, we become perfectly 
 fatisfied as to the truth of all the conclu- 
 fions we have paffed through, in as much 
 as they are now feen to Hand upon the 
 firm and immoveable found ad on of our 
 intuitive perceptions. And as we arrived 
 at this certainty by tracing our conclufions 
 backward to the original principles from 
 R which 
 
I '3° ; 
 
 which they are deduced ; fo we may at 
 any time renew it by a direft contrary 
 procefs, if, beginning with thefe prin- 
 ciples, we carry the train of our thoughts 
 forward, until they lead us, by a con- 
 nected chain of proofs, to the very lad 
 conclufion of the feries. 
 
 Hence it appears, that, in difpoiing and 
 putting together our thoughts (either for 
 our own ufe, — that the difcoveries which 
 we have made may at all times be open 
 to the review of our minds ; or for the 
 communicating or unfolding of thefe dif- 
 coveries to others), there are two ways of 
 proceeding, equally within our choice. 
 For we may fo propofe the truths relating 
 to any part of knowledge, as they pre- 
 fented thcmfelves to the mind in rhe man- 
 ner of inveftigation ; carrying on the feries 
 of proofs in a reverfe order, until they at 
 laft terminate in firft principles : or, be- 
 ginning 
 
( **• ) 
 
 ginning with thefe principles, we may 
 take the contrary way ; and from them 
 deduce, by a direcl train of reafoning, 
 all the feveral proportions we want to 
 eftablifh. This diverfity, in the manner 
 of arranging our thoughts, gives rife to 
 the two-fold divifion of method eftablifh- 
 ed by logicians. For method, according 
 to their ufe of the word, is nothing elfe 
 than the order and difpofition of our 
 thoughts relating to any fubjccl:. When 
 truths are fo difpofed and put together, 
 as they were or might have been difcover- 
 ed, this is called the analytic method^ or 
 the method of ' rcfolution ; in as much as it 
 traces things backward to their fource, 
 and refolves knowledge into its firA and 
 original principles. When, on the other 
 hand, truths are deduced from thefe firfl: 
 principles, and connected according to their 
 mutual dependence, in (o much that the 
 
 truths 
 
( *3 2 ) 
 
 truths firfl in order tend always to the 
 demonflration of thofe that follow, this 
 conflitutes what we call the fynthetick me- 
 thod, or method of compofition. The firfl 
 of thefe has alfo obtained the name of the 
 method of invention ; becaufe it obferves 
 the order in which our thoughts fucceed 
 one another in the invention or difcovery 
 of truth : the other again is often deno- 
 minated the method offcience ; in as much 
 as in laying our thoughts before others, 
 we generally chufe to proceed in the fyn- 
 thetick manner, deducing them from their 
 fir ft principles. 
 
 THE END, 
 

 (rtrtt 
 
 /a'**} 
 
 CiJ 
 
 L , , Li 
 
■* 
 
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