Online research in philosophy

According to a prominent line of thought, we can be physicalists, but not reductive physicalists, by holding that mental and other ‘higher-level’ or ‘nonbasic’ properties — properties that are not obviously physical properties — are all physically realized. Spelling this out requires an account of realization, an account of what it is for one property to realize another. And while several accounts of realization have been advanced in recent years,1 my interest here is in the ‘subset view,’ which has often been invoked explicitly in defense of nonreductive physicalist positions.2 The subset view holds that property realization consists in the powers of one property having as a subset the powers of another; ..

The realization relation is commonly explicated via, or identified with, the causal role playing relation. However, the realization relation does not formally match the causal role playing relation. While realization is a relation between a base realizer property and a single higher level realized property, I argue that the causal role playing relation as typically defined is a relation between a base property and two higher-level role properties. Advocates of using causal role playing to explicate realization must therefore decide which of the two kinds of role property they identify with realized properties; I argue that neither choice is good, and the fact that one must make a choice is worse. A search for a new way of defining realization is in order.

This paper interprets and criticizes some of the views presented in Sydney Shoemaker’s book, Physical Realization (Oxford University Press, 2007), on the topic of how mental properties are realized by physical properties, given that, on his view, human persons are not even token-identical with human bodies.

It is commonly believed that there is a fundamental incompatibility between multiple realization and type identity in the philosophy of mind. This claim can be challenged, however, since a single neural type may be realized by different microphysical types. In this case, the identity statement would connect the psychological and the neural type, while the neural type, in turn, could be multiply realized by different microphysical types. Such a multiple realization of higher level types occurs quite frequently even within physics and it should be acceptable for physicalism in general.

Thomas Polger and Laurence Shapiro argue that Carl Gillett's much publicized dimensioned theory of realization is incoherent, being subject to a reductio. Their argument turns on the fact that Gillett's definition of realization makes property instances the exclusive relata of the realization relation, while his belief in multiple realization implies its denial, namely, that properties are the relata of the realization relation on occasions of multiple realization. Others like Sydney Shoemaker have also expressed their view of realization in terms of property instances, yet they too have accepted the multiple realizability of properties. Thus I am interested in the more general issue raised by Polger and Shapiro's argument. Specifically, I show how to supplement a theory of realization with a category-inclusive auxiliary assumption, which avoids the stated reductio. I then offer a few reasons to justify the proposed category-inclusive view of realization, making some comparisons to supervenience and causation along the way.

Abstract: There has recently been controversy over the existence of 'multiple realization' in addition to some confusion between different conceptions of its nature. To resolve these problems, we focus on concrete examples from the sciences to provide precise accounts of the scientific concepts of 'realization' and 'multiple realization' that have played key roles in recent debates in the philosophy of science and philosophy of psychology. We illustrate the advantages of our view over a prominent rival account ( Shapiro, 2000 and 2004 ) and use our work to rebut recent objections to the long-standing claim that psychological properties are multiply realized. For we use scientific evidence, in combination with our more precise theoretical framework, to show that we have strong reason to believe that psychological properties are indeed multiply realized both at the biochemical and neuronal levels.

Let thin properties be properties shared by coincident entities, e.g., a person and her body, and thick properties ones that are not shared. Thick properties entail sortal properties, e.g., being a person, and the associated persistence conditions. On the first account of realization defined here, the realized property and its realizers will belong to the same individual. This restricts the physical realizers of mental properties, which are thick, to thick physical properties. We also need a sense in which mental properties can be realized in thin physical properties shared by a person and her body. Defining this in turn requires defining a sense in which the instantiations of sortal properties and of thick properties are realized in micro-structural states of affairs. A fourth notion of realization is needed to allow for the possibility of coincident entities that share a sortal property, e.g., coincident persons.

Thomas Polger and Lawrence Shapiro (or P&S) have recently (2008) criticized ?causal-mechanist? views of realization that dominate research in the philosophy of mind and metaphysics of science. P&S offer the internal criticism that any account of realization focusing upon property instances, as views of causal-mechanist realization routinely do, must lead to incoherence about multiple realization. P&S's argument highlights important issues about property instances that have recently been neglected, as well as raising a challenge to the standard approach to understanding the non-causal relations between properties and their instances in the sciences. In response, I clarify some important background issues about property instances and their relations to properties which show why P&S's main argument fails. In addition, I provide a second reason to doubt their argument by highlighting reasons to think that instances, as well as properties, are plausibly sometimes multiply realized in the sciences.

Some scientists and philosophers have claimed that there is a converse to multiple realizability. While a given higher-level property can be realized by different lower-level properties (multiple realizability), a given lower-level property can in turn serve to realize different higher-level properties (this converse I dubbed the unfortunately obscure "constructival plasticity" to emphasize the constructive metaphysics involved when realizing properties generate realized properties in the stated way). I begin by defining multiple realizabilty in a formal way, then turn to the relation in question. By my analysis, for the converse claim to be true, a lower-level property G1 that realizes a higher-level F must be taken in conjunction with some other base condition G2 so that a difference in G2 allows G1 to determine some other higher-level property E but not F (otherwise there would be violations of supervenience). The realization law thus has the form: (G1 & G2) => F. As such, the base property G1 is insufficient by itself to produce F. It is an insufficient but necessary part of a sufficient condition. I also point out that this makes the realization base property an INUS condition, if combined with multiple realizability. Specifically, if F is multiply realized by properties other than the pair G1 and G2, then G1 is an insufficient but necessary part of an unnecessary but sufficient condition.