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In philosophy, physicalism is the ontological thesis that "everything is physical", that there is "nothing over and above" the physical,〔See Smart, 1959〕 or that everything supervenes on the physical.〔 Physicalism is a form of ontological monism—a "one substance" view of the nature of reality as opposed to a "two-substance" (dualism) or "many-substance" (pluralism) view. Both the definition of "physical" and the meaning of physicalism have been debated. Physicalism is closely related to materialism. Physicalism grew out of materialism with the success of the physical sciences in explaining observed phenomena. The terms are often used interchangeably, although they are sometimes distinguished, for example on the basis of physics describing more than just matter (including energy and physical law). Common arguments against physicalism include both the philosophical zombie argument〔 and the multiple observers argument,〔 that the existence of a physical being may imply zero or more distinct conscious entities. == Definition of physical == The use of "physical" in physicalism is a philosophical concept and can be distinguished from alternative definitions found in the literature (e.g. Popper defined a physical proposition to be one which can at least in theory be denied by observation〔). A "physical property", in this context, may be a metaphysical or logical combination of properties which are physical in the ordinary sense. It is common to express the notion of "metaphysical or logical combination of properties" using the notion of supervenience: A property ''A'' is said to supervene on a property ''B'' if any change in ''A'' necessarily implies a change in ''B''.〔See Bennett and McLaughlin, 2011〕 Since any change in a combination of properties must consist of a change in at least one component property, we see that the combination does indeed supervene on the individual properties. The point of this extension is that physicalists usually suppose the existence of various abstract concepts which are non-physical in the ordinary sense of the word; so physicalism cannot be defined in way that denies the existence of these abstractions. Also, physicalism defined in terms of supervenience does not entail that all properties in the actual world are type identical to physical properties. It is, therefore, compatible with multiple realizability.〔See Putnam, 1967〕 From the notion of supervenience, we see that, assuming that mental, social, and biological properties supervene on physical properties, it follows that two hypothetical worlds cannot be identical in their physical properties but differ in their mental, social or biological properties.〔 Two common approaches to defining "physicalism" are the theory-based and object-based approaches. The theory-based conception of physicalism proposes that "a property is physical if and only if it either is the sort of property that physical theory tells us about or else is a property which metaphysically (or logically) supervenes on the sort of property that physical theory tells us about".〔 Likewise, the object-based conception claims that "a property is physical if and only if: it either is the sort of property required by a complete account of the intrinsic nature of paradigmatic physical objects and their constituents or else is a property which metaphysically (or logically) supervenes on the sort of property required by a complete account of the intrinsic nature of paradigmatic physical objects and their constituents". Physicalists have traditionally opted for a "theory-based" characterization of the physical either in terms of current physics,〔See e.g., Smart, 1978; Lewis, 1994.〕 or a future (ideal) physics.〔See e.g., Poland, 1994; Chalmers, 1996; Wilson, 2006.〕 These two theory-based conceptions of the physical represent both horns of Hempel's dilemma〔Andrew Melnyk should apparently be credited with having introduced this name for Hempel's argument. See Melnyk, 1997, p.624〕 (named after the late philosopher of science and logical empiricist Carl Gustav Hempel): an argument against theory-based understandings of the physical. Very roughly, Hempel's dilemma is that if we define the physical by reference to current physics, then physicalism is very likely to be false, as it is very likely (by pessimistic meta-induction〔see Vincente, 2011〕) that much of current physics is false. But if we instead define the physical in terms of a future (ideal) or completed physics, then physicalism is hopelessly vague or indeterminate.〔See Hempel, 1969, pp.180-183; Hempel, 1980, pp.194-195.〕 While the force of Hempel's dilemma against theory-based conceptions of the physical remains contested,〔For a recent defence of the first horn see Melnyk, 1997. For a defence of the second, see Wilson, 2006.〕 alternative "non-theory-based" conceptions of the physical have also been proposed. Frank Jackson (1998) for example, has argued in favour of the aforementioned "object-based" conception of the physical.〔See Jackson, 1998, p.7; Lycan, 2003.〕 An objection to this proposal, which Jackson himself noted in 1998, is that if it turns out that panpsychism or panprotopsychism is true, then such a non-materialist understanding of the physical gives the counterintuitive result that physicalism is, nevertheless, also true since such properties will figure in a complete account of paradigmatic examples of the physical. David Papineau〔See Papineau, 2002〕 and Barbara Montero〔See Montero, 1999〕 have advanced and subsequently defended〔See Papineau and Montero, 2005〕 a "via negativa" characterization of the physical. The gist of the via negativa strategy is to understand the physical in terms of what it is not: the mental. In other words, the via negativa strategy understands the physical as "the non-mental". An objection to the via negativa conception of the physical is that (like the object-based conception) it doesn't have the resources to distinguish neutral monism (or panprotopsychism) from physicalism.〔See e.g., Judisch, 2008〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「physicalism」の詳細全文を読む スポンサード リンク
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