Physicalism and Metaphysical Naturalism

by

D. Gene Witmer

• LAST REVIEWED: 15 December 2022
• LAST MODIFIED: 30 March 2015
• DOI: 10.1093/obo/9780195396577-0258

Introduction

Much of contemporary metaphysical work is motivated in some way by the desire to accommodate what the natural sciences, especially physics, have taught us about the world. This motivation has drawn many philosophers to endorse doctrines variously described as physicalism, materialism, or naturalism. “Physicalism” and “materialism” are often treated as interchangeable names for a single doctrine that may be crudely expressed as the claim that everything that exists is physical. By contrast, “naturalism” is widely acknowledged to be ambiguous between at least two sorts of positions. Epistemological naturalism is the view that knowledge is best gained (perhaps: can only be gained) via the methods of science (perhaps: the methods of natural science). Metaphysical naturalism is often thought of as making a global ontological claim akin to physicalism—perhaps the claim that everything that exists is natural, where some explication of “natural” is evidently crucial. (“Naturalism” without qualification shall here be understood as referring to the metaphysical doctrine.) It is often suspected on the part of non-naturalists that a self-declared naturalist is really just a physicalist under a different label. Both doctrines are thought to have significant consequences for our understanding of the world, especially human aspects of the world and the nature of mentality. They may also have implications for our understanding of moral properties, abstract objects, the possibility of knowledge, and other familiar items of philosophical investigation. A global metaphysical theory of this sort induces what are known (following Frank Jackson in From Metaphysics to Ethics; see Jackson 1998, cited under Central Monographs) as “placement location problems”: the problem of locating in a wholly physical or natural world those things that seem not to be wholly physical or natural. Debates about these metaphysical doctrines often focus on the prospects for solving such placement problems, where a failure may justify an elimination of the thing in question or a rejection of the global doctrine. Other debates focus on the proper formulation and understanding of the doctrines (e.g., what is meant by calling an entity physical?), whether and how it might be justified (e.g., what in the development of natural science could justify the claim that everything is natural?), and its implications for science and the proper treatment of placement problems (e.g., does physicalism require all sciences to reduce to physics?).

General Overviews

While physicalism and naturalism influence an enormous amount of philosophical work, general overviews are mostly confined either to portions of larger works where the main focus lies elsewhere or entries in philosophical companions or guides. There are many of the latter to be found in the recent proliferation of handbooks, companions and similar volumes, especially those focusing on mind, metaphysics, or philosophy of science. Three of those may be spotlighted here. Stoljar’s “Physicalism” (Stoljar 2009) and David Papineau’s “Naturalism” (Papineau 2009) both appear as entries in the online Stanford Encyclopedia of Philosophy, and the Continuum Companion to Metaphysics includes Witmer 2012 as a guide to both. By way of books, Stoljar 2010 is a less ecumenical monograph that provides an excellent introduction and overview, and Ritchie 2008 serves as a textbook addressing both epistemic and metaphysical varieties of naturalism. It is also advisable to get a partial overview of the issues surrounding physicalism by surveying the development of the mind-body problem since the middle of the 20th century, as that discussion has done much to influence the more general metaphysical discussions.

• Kim, Jaegwon. Philosophy of Mind. 3d ed. Boulder, CO: Westview, 2010.

  NNNAn introductory text that focuses primarily on the mind-body problem, especially good for its discussion of type identity and functionalist accounts. May fruitfully be read with an eye toward physicalism as a general thesis about all phenomena, not just the mind.

• Papineau, David. “Naturalism” In The Stanford Encyclopedia of Philosophy. Edited by Edward N. Zalta. Stanford, CA: Stanford University, 2009.

  NNNA review of several positions associated with naturalism without an attempt to provide a definition of naturalism itself. Metaphysical issues reviewed include the status of normative, mathematical, and modal facts and whether they can be located in a natural world.

• Ritchie, Jack. Understanding Naturalism. Stocksfield, UK: Acumen, 2008.

  NNNA concise textbook on naturalism, covering both epistemic and metaphysical varieties. The fourth and fifth chapters focus primarily on metaphysics, including discussion of a non-physicalist metaphysical naturalism. A usefully ecumenical, wide-ranging work.

• Stoljar, Daniel. “Physicalism” In The Stanford Encyclopedia of Philosophy. Edited by Edward N. Zalta. Stanford, CA: Stanford University Press, 2009.

  NNNA survey focused largely but not exclusively on questions of formulation, including attention to supervenience, identity, a priori versus a posteriori varieties of physicalism, and the key question as to how “physical” is to be understood.

• Stoljar, Daniel. Physicalism. New York: Routledge, 2010.

  NNNA systematic overview touching on all major issues regarding physicalism. Suitable as an introduction while also making a signal contribution to the literature, arguing that no formulation both makes sense of philosophical debates about physicalism while being adequate to the intuitive understanding of the doctrine.

• Witmer, D. Gene. “Naturalism and Physicalism.” In The Continuum Companion to Metaphysics. Edited by Neil A. Manson and Robert W. Barnard. New York: Continuum, 2012.

  NNNA substantial guide providing an overview of both physicalism and metaphysical naturalism, reviewing both questions of formulation and justification for both doctrines. Includes a diagnostic strategy for understanding talk of naturalism as a metaphysical thesis.