Physicalism

by

Andrew Melnyk

• LAST REVIEWED: 09 May 2023
• LAST MODIFIED: 24 November 2020
• DOI: 10.1093/obo/9780195396577-0267

Introduction

In the sense relevant to this article, physicalism (or materialism; the two terms are used interchangeably in the literature) is a comprehensive view about the nature of the world to the effect that every phenomenon whatever is, or is at bottom, physical. As such, it obviously raises issues about the place of phenomenal consciousness, intentionality, and morality—among other things—in a purely physical world. But it also raises issues that are independent of these familiar special cases, and it is to them that this article is devoted. One cluster of issues concerns how to formulate a thesis of physicalism that is neither obviously true nor obviously false, and significant if true. This has generally been thought to require specifying (1) a narrow sense of “physical,” perhaps linked to physics, and (2) some relation of being nothing over and above such that phenomena that are not physical in the narrow sense can be claimed to be nothing over and above phenomena that are physical in the narrow sense; candidates for such a relation are identity, supervenience, realization, and, most recently, grounding. A second cluster of issues concerns the implications of physicalism. Is physicalism a posteriori? Is it (if true at all) necessarily true? Can physicalism avoid commitment to physical reductionism? If so, how, and if not, then is that a problem for physicalism? Is physicalism consistent with the countless claims of causation and causal explanation made in the special sciences and in everyday life? (This last issue overlaps so much with the problems of mental causation, which have a vast literature of their own, that it is not addressed in the present article; the reader is directed to the separate article on mental causation.) A third cluster of issues concerns how in principle we could have, and whether in fact we do have, empirical evidence that physicalism is true—or of course that it is false. For example, is it true that for every (narrow sense) physical effect there is a sufficient physical cause, that is, that the causal closure of the physical holds? And if it does, then can a case for physicalism be built upon it? Can observed correlations between reported mental states (say) and brain states provide reason to think that mental states just are brain states? A fourth cluster of issues concerns alternatives to physicalism. Aside from traditional forms of mind-body dualism, what possible alternatives are there? For example, panpsychism holds that phenomenal properties are the intrinsic aspects of the properties known in physics through their causal or structural aspects. Is this a physicalist view or not? What scope is there for theses of pluralism, or of neutral monism?

General Overviews

There are no satisfactory general overviews of all the issues mentioned in the Introduction. Kim 1998, however, provides an excellent introduction to most of the main ones, and should be accessible to intermediate and advanced undergraduate philosophy students. Stoljar 2017 is a critical survey of—for the most part—the issues surrounding the formulation of physicalism; but it is aimed at a more sophisticated readership. Neither of these works brings any empirical material into their discussions. Oppenheim and Putnam 1958, though dated philosophically, usefully assembles empirical evidence (as available in 1958) for thinking that the world boils down to physics.

• Kim, Jaegwon. Mind in a Physical World: An Essay on the Mind-Body Problem and Mental Causation. Cambridge, MA: Massachusetts Institute of Technology Press, 1998.

  The world’s leading exponent of the metaphysics of mind, until his death in 2019, explores the role of supervenience and realization in formulating physicalism, plus the implications of physicalism for causation and reductionism.

• Oppenheim, Paul, and Hilary Putnam. “Unity of Science as a Working Hypothesis.” In Minnesota Studies in the Philosophy of Science. Vol. 2. Edited by Herbert Feigl, Michael Scriven, and Grover Maxwell, 3–35. Minneapolis: University of Minnesota Press, 1958.

  Classic paper arguing on empirical grounds that science is unified in the sense that all phenomena are reducible to physical phenomena; but the reducibility intended does not require that each special science phenomenon be type-identical with some physical phenomenon. Perhaps best viewed as implying eliminative physicalism.

• Stoljar, Daniel. “Physicalism.” In The Stanford Encyclopedia of Philosophy. Edited by Edward N. Zalta. Stanford, CA: Stanford University, 2017.

  Philosophically stimulating commentary on attempts to characterize “physical” in the narrow sense and to specify the relation of being nothing over and above.