Mind, Matter, and Nature

5. Problems for Materialism

132 Chapter 5 Problems for Materialism In our last chapter we considered several philosophical approaches to psychological states that are at least consistent with materialism. On the one hand we considered eliminative materialism and logical behaviorism, but as we found those to be rather problematic, we will leave them aside in this chapter. On the other hand, we considered that various versions of the identity theory and functionalism enjoy a great deal more plausibility, and hereafter when I speak of materialism, I will have these sorts of positions in mind.1 What these latter theories commonly claim is that when something has a sensation or thought, that token of a psychological state is a token of a physical state. According to token-identity theorists and functionalists, but not type-identity theorists, other tokens of that psychological type might have been realized by tokens of another neurophysiological state type (or possibly a nonphysical state type), and to explain this they use the notion of superve1 . As we discussed in the last chapter, we should be careful when speaking about functionalism in the same breath as materialism, because functionalism is not a materialist theory per se (though it is consistent with materialism). 133 Problems for Materialism nience. Thus, whether he advances a classic type-identity theory, token-identity theory, or some version or other of functionalism, the materialist claims that an organism’s (or a machine’s) having a sensation or thought need not involve nonphysical properties or substances. In this chapter, we will consider objections from philosophers who believe that these various materialist theories fail, because they all leave something essential out of the account of sensation, thought, and moral-intellectual agency; that is, there is some aspect of sensation, thought, or agency that is left unaccounted for by the materialist theories, and consequently we cannot say (at least for now) that psychological beings in the actual world are just physical beings. In what follows, we will first consider objections to materialism based on the qualitative nature of sensations. We will then consider objections based on the intentional nature of thought, and finally we will consider objections to materialism based on the nature of moral and intellectual agency. Note, however , that these objections do not necessarily amount to a rejection of naturalism, but only of materialism. As we shall see in the following chapter, there are versions of naturalism that concede that psychological states are neither strictly reducible to nor supervenient on physical states while claiming that psychological states can nevertheless be explained by underlying physical phenomena. Before we turn to nonmaterialist, naturalist positions, we first need to discuss whether there is any good reason to reject materialism. Qualia Arguments—Bats, Cloistered Neuroscientists, and Zombies Thomas Nagel points out that “if physicalism is to be defended , the phenomenological features [of psychological states] must be given a physical account.”2 The materialist must then 2. Thomas Nagel, “What Is It Like to Be a Bat?” reprinted in The Philosophy of Mind: Classical and Contemporary Readings, ed. David Chalmers (Oxford: Oxford University Press, 2002), 220. Originally printed in Philosophical Review 83, no. 4 (1974): 435–50; Nagel 134 Problems for Materialism construct an entirely physical story about sensations, but, “when we examine their subjective character it seems that such a result is impossible,” because every sensation “is essentially connected with a single point of view, and it seems inevitable that an objective , physical theory will abandon that point of view.”3 Nagel argues from the fact that the first-person perspective of sensations can be neither denied nor captured in any physical account. Philosophers call the qualitative and subjective aspects of sensations “qualia” (the plural of the Latin quale for “quality”), so objections to materialism like Nagel’s are often called qualia arguments. He makes his case by appeal to the experiential life of the bat. Bats, as Nagel points out, are mammals with a very sophisticated perceptual apparatus, and there can be no doubt that they have experience , that is, there is some way that it is like to be a bat, in the sense that there is no way that it is like to be a stone. There is such a thing as bat awareness or bat feelings. Bats are primarily aware of the world through echolocation (a sort of biological sonar system); they locate prey and navigate by echoes rebounding off objects from the high frequency sounds the...