Physical object - Wikipedia Physical object From Wikipedia, the free encyclopedia Jump to navigation Jump to search For the concept in philosophy, see Object (philosophy). Identifiable collection of matter This article does not cite any sources. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. Find sources: "Physical object" – news · newspapers · books · scholar · JSTOR (July 2012) (Learn how and when to remove this template message) A bubble of exhaled gas in water In common usage, a physical object or physical body (or simply an object or body) is a collection of matter within a defined contiguous boundary in three-dimensional space.[citation needed] The boundary must be defined and identified by the properties of the material. The boundary may change over time. The boundary is usually the visible or tangible surface of the object. The matter in the object is constrained (to a greater or lesser degree) to move as one object. The boundary may move in space relative to other objects that it is not attached to (through translation and rotation). An object's boundary may also deform and change over time in other ways. Also in common usage, an object is not constrained to consist of the same collection of matter. Atoms or parts of an object may change over time. An object is defined by the simplest representation of the boundary consistent with the observations. However the laws of Physics only apply directly to objects that consist of the same collection of matter. In physics, an object is an identifiable collection of matter, which may be constrained by an identifiable boundary, and may move as a unit by translation or rotation, in 3-dimensional space. Each object has a unique identity, independent of any other properties. Two objects may be identical, in all properties except position, but still remain distinguishable. In most cases the boundaries of two objects may not overlap at any point in time. The property of identity allows objects to be counted. Examples of models of physical bodies include, but are not limited to a particle, several interacting smaller bodies (particles or other), and continuous media. The common conception of physical objects includes that they have extension in the physical world, although there do exist theories of quantum physics and cosmology which may challenge[how?] this. In modern physics, "extension" is understood in terms of the spacetime: roughly speaking, it means that for a given moment of time the body has some location in the space, although not necessarily a point. A physical body as a whole is assumed to have such quantitative properties as mass, momentum, electric charge, other conserving quantities, and possibly other quantities. An object with known composition and described in an adequate physical theory is an example of physical system. Contents 1 In common usage 2 Classical mechanics 3 Quantum mechanics 4 String theory 5 In psychology 6 In philosophy 7 See also 8 External links In common usage[edit] An object is known by the application of senses. The properties of an object are inferred by learning and reasoning based on the information perceived. Abstractly, an object is a construction of our mind consistent with the information provided by our senses, using Occam's razor. In common usage an object is the material inside the boundary of an object, in 3-dimensional space. The boundary of an object is a contiguous surface which may be used to determine what is inside, and what is outside an object. An object is a single piece of material, whose extent is determined by a description based on the properties of the material. An imaginary sphere of granite within a larger block of granite would not be considered an identifiable object, in common usage. A fossilized skull encased in a rock may be considered an object because it is possible to determine the extent of the skull based on the properties of the material. For a rigid body, the boundary of an object may change over time by continuous translation and rotation. For a deformable body the boundary may also be continuously deformed over time in other ways. An object has an identity. In general two objects with identical properties, other than position at an instance in time, may be distinguished as two objects and may not occupy the same space at the same time (excluding component objects). An object's identity may be tracked using the continuity of the change in its boundary over time. The identity of objects allows objects to be arranged in sets and counted. The material in an object may change over time. For example, a rock may wear away or have pieces broken off it. The object will be regarded as the same object after the addition or removal of material, if the system may be more simply described with the continued existence of the object, than in any other way. The addition or removal of material may discontinuously change the boundary of the object. The continuation of the objects identity is then based on the description of the system by continued identify being simpler than without continued identity. For example, a particular car might have all its wheels changed, and still be regarded as the same car. The identity of an object may not split. If an object is broken into two pieces at most one of the pieces has the same identity. An object's identity may also be destroyed if the simplest description of the system at a point in time changes from identifying the object to not identifying it. Also an object's identity is created at the first point in time that the simplest model of the system consistent with perception identifies it. An object may be composed of components. A component is an object completely within the boundary of a containing object. Classical mechanics[edit] In classical mechanics a physical body is collection of matter having properties including mass, velocity, momentum and energy. The matter exists in a volume of three-dimensional space. This space is its extension. Under Newtonian gravity the gravitational field further away than the furthest extent of an object is determined only by the mass and the position of the center of mass. Interactions between objects are partly described by orientation and external shape. In continuum mechanics an object may be described as a collection of sub objects, down to an infinitesimal division, which interact with each other by forces which may be described internally by pressure and mechanical stress. Quantum mechanics[edit] In quantum mechanics an object is a particle or collection of particles. Until measured, a particle does not have a physical position. A particle is defined by a probability distribution of finding the particle at a particular position. There is a limit to the accuracy with which the position and velocity may be measured. A particle or collection of particles is described by a quantum state. These ideas vary from the common usage understanding of what an object is. String theory[edit] In particle physics, there is a debate as to whether some elementary particles are not bodies, but are points without extension in physical space within space-time, or are always extended in at least one dimension of space as in string theory or M theory. In psychology[edit] In some branches of psychology, depending on school of thought, a physical object has physical properties, as compared to mental objects. In (reductionistic) behaviorism, objects and their properties are the (only) meaningful objects of study. While in the modern day behavioral psychotherapy it is still only the means for goal oriented behavior modifications, in Body Psychotherapy it is not a means only anymore, but its felt sense is a goal of its own. In cognitive psychology, physical bodies as they occur in biology are studied in order to understand the mind, which may not be a physical body, as in functionalist schools of thought. In philosophy[edit] Further information: Ontology and Metaphysics A physical body is an enduring object that exists throughout a particular trajectory of space and orientation over a particular duration of time, and which is located in the world of physical space (i.e., as studied by physics). This contrasts with abstract objects such as mathematical objects which do not exist at any particular time or place. Examples are a cloud, a human body, a weight, a billiard ball, a table, or a proton. This is contrasted with abstract objects such as mental objects, which exist in the mental world, and mathematical objects. Other examples that are not physical bodies are emotions, the concept of "justice", a feeling of hatred, or the number "3". In some philosophies, like the idealism of George Berkeley, a physical body is a mental object, but still has extension in the space of a visual field. See also[edit] Abstract object theory Deformable body Human body Rigid body Non-physical entity External links[edit] Media related to Physical objects at Wikimedia Commons v t e Metaphysics Metaphysicians Parmenides Plato Aristotle Plotinus Duns Scotus Thomas Aquinas Francisco Suárez Nicolas Malebranche René Descartes John Locke David Hume Thomas Reid Immanuel Kant Isaac Newton Arthur Schopenhauer Baruch Spinoza Georg W. F. Hegel George Berkeley Gottfried Wilhelm Leibniz Christian Wolff Bernard Bolzano Hermann Lotze Henri Bergson Friedrich Nietzsche Charles Sanders Peirce Joseph Maréchal Ludwig Wittgenstein Martin Heidegger Alfred N. Whitehead Bertrand Russell G. E. Moore Jean-Paul Sartre Gilbert Ryle Hilary Putnam P. F. Strawson R. G. Collingwood Rudolf Carnap Saul Kripke W. V. O. Quine G. E. M. Anscombe Donald Davidson Michael Dummett D. M. Armstrong David Lewis Alvin Plantinga Héctor-Neri Castañeda Peter van Inwagen Derek Parfit Alexius Meinong Ernst Mally Edward N. Zalta more ... Theories Abstract object theory Action theory Anti-realism Determinism Dualism Enactivism Essentialism Existentialism Free will Idealism Libertarianism Liberty Materialism Meaning of life Monism Naturalism Nihilism Phenomenalism Realism Physicalism Platonic idealism Relativism Scientific realism Solipsism Subjectivism Substance theory Truthmaker theory Type theory Concepts Abstract object Anima mundi Being Category of being Causality Causal closure Choice Cogito, ergo sum Concept Embodied cognition Essence Existence Experience Hypostatic abstraction Idea Identity Information Insight Intelligence Intention Linguistic modality Matter Meaning Memetics Mental representation Mind Motion Nature Necessity Notion Object Pattern Perception Physical object Principle Property Qualia Quality Reality Relation Soul Subject Substantial form Thought Time Truth Type–token distinction Universal Unobservable Value more ... Related topics Axiology Cosmology Epistemology Feminist metaphysics Interpretations of quantum mechanics Mereology Meta- Ontology Philosophy of mind Philosophy of psychology Philosophy of self Philosophy of space and time Teleology Theoretical physics Category  Philosophy portal v t e Into matter Object > Molecule > Atom > Subatomic particle (Composite particle Elementary particle) Retrieved from "https://en.wikipedia.org/w/index.php?title=Physical_object&oldid=994299037" Categories: Concepts in metaphysics Concepts in physics Mechanics Ontology Physical objects Main topic articles Hidden categories: Articles with short description Short description is different from Wikidata Articles lacking sources from July 2012 All articles lacking sources All articles with unsourced statements Articles with unsourced statements from June 2019 Wikipedia articles needing clarification from June 2013 Commons category link is on Wikidata Navigation menu Personal tools Not logged in Talk Contributions Create account Log in Namespaces Article Talk Variants Views Read Edit View history More Search Navigation Main page Contents Current events Random article About Wikipedia Contact us Donate Contribute Help Learn to edit Community portal Recent changes Upload file Tools What links here Related changes Upload file Special pages Permanent link Page information Cite this page Wikidata item Print/export Download as PDF Printable version In other projects Wikimedia Commons Languages العربية Беларуская Беларуская (тарашкевіца)‎ भोजपुरी Български Català Чӑвашла Čeština Dansk Deutsch Eesti Ελληνικά Español Esperanto فارسی Français 한국어 हिन्दी Hrvatski Italiano Latina Latviešu Lëtzebuergesch Magyar Na Vosa Vakaviti Nederlands 日本語 Norsk bokmål Polski Português Русский Simple English Slovenčina Slovenščina کوردی Srpskohrvatski / српскохрватски Suomi Svenska Türkçe Українська Tiếng Việt Võro 吴语 粵語 中文 Edit links This page was last edited on 15 December 2020, at 00:38 (UTC). 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