Abstract

Theo C. Meyering, in “Mind Matters: Physicalism and the Autonomy of the Person,” takes yet a third approach to the issue of reduction. He states that “if (true, downward) mental causation implies nonreducibility [as Stoeger and Murphy argue] and physicalism implies the converse, it is hard to see how these two views could be compatible.” Meyering distinguishes three versions of reductionism: radical (industrial strength) physicalism; ideal (regular strength) physicalism, and mild or token physicalism. Radical physicalism asserts that all special sciences are reducible to physics in the sense that their laws can be deduced via bridge laws from those of physics. Ideal physicalism asserts that while it is practically impossible to reduce the special sciences, such reduction would be possible were there an ideally complete physics" (Note: This distinction parallels Stoeger’s recognition that epistemological reducibility is relative to the meaning of “laws of nature). Token physicalism is ontologically reductionist: there are no events that are not “token-identical” with some physical event or other (Note: See above, sec. 3.3). However, there are no identities between higher-level and lower- level types of events; consequently some events described by the special sciences have no physical explanation at all. All of these reductionist positions are to be contrasted with compositional (milder than mild) physicalism, which asserts that some higher-level events are not even token-identical with physical events because the higher-level event (say, a crash in the stock market) is constituted by innumerable physical particulars in all sorts of states and interactions. Meyering then surveys some of the existing arguments for the nonreducibility of the special sciences. One of the most important is the argument from multiple realizability. The claim is that economics, for example, is not reducible to physics because economic concepts (for example, monetary exchange) are “wildly multiply realizable” (for example, using coins, strings of wampum, signing a check). Thus, there can be no bridge laws and no reduction. Such an argument, however, only cuts against radical physicalism, not the weaker (and a priori more plausible) ideal physicalism. A stronger argument for the indispensability of special-science explanations is based on the role of functional explanations. For example, the functional description of aspirin as an analgesic is in some instances a more useful explanation of its causal role (relieving a headache) than is its description as the chemical level. Meyering’s own contribution focuses neither on multiple realizability of supervenient properties nor on multiple “fillers” of functional roles, but on “multiple supervenience.” In particular, a single subvenient state of affairs (for example, a cloud of free electrons permeating the metal of which a ladder is constructed) may realize a variety of supervenient dispositional properties (in this case, electrical conductivity, thermal conductivity, opacity). An explanation (say, of the cause of a deadly accident) requires reference to the dispositional property (electrical conductivity), not merely to the subvenient property. Meyering argues that it is this possibility of multiple supervenience, not multiple realizability, that gives arguments against reduction based on functional properties their real force. Downward causation, then, can be understood in terms of selective activation of one of several dispositional properties of a lower-level state, and thus can be assigned a stable place in our picture of how the world is organized without upsetting our conception of physics as constituting a closed and complete system of physical events.