UC Santa Barbara

I defend abundant ontologies that include ordinary midsize composite objects—the things we seem to see, feel, and touch around us—and other composite objects like molecules and cells. To this end, I argue that in general, appeals to our best scientific theories support and do not undermine our beliefs in these objects. My main targets are those who appeal to the results of our best scientific theories to foster object skepticism, or who argue that object-free scientific theories are better than the original theories. I mount my defense in two ways. First, I defend our object beliefs against skeptical arguments rooted in appeals to evolutionary biology and the evolution of our own perceptual systems. Second, I advance an original argument that we should believe in composite objects because they are indispensable to our best scientific theories.In Chapter 1 I argue that eliminativists running evolutionary debunking arguments face a self-defeat problem: their conclusion undermines the scientific support for one of their premises, because evolutionary biology depends on our object beliefs. Using work on reductionism and multiple realizability from the philosophy of science, I argue that it will not suffice for an eliminativist debunker to simply appeal to a paraphrased version of evolutionary theory that does not mention or predict composite objects. In fact, the debunker must pay a high price in terms of parsimony to recoup the generality of the original, object-laden theory. An object debunker’s skeptical conclusion rests on the claim that our object beliefs are not best explained by the object facts, but rather by our evolved predispositions to perceptually represent the world as containing composite objects even if they don’t exist. In Chapter 2, I show that a hybrid externalist view of perceptual representation can provide a composite-friendly explanation of our object beliefs that meets the object debunker’s challenge. Such a view also avoids certain objections sometimes raised against externalist views, such as the possibility of illicit a priori reasoning about the external world or the inability to accommodate the possibility of reliable misrepresentations. In Chapter 3, I argue that we should believe in some composite objects because they are indispensable to our best sciences. This argument is based on arguments put forth in the philosophy of mathematics to support of beliefs in mathematical objects. I compare conventional theories like evolutionary biology to their object-free rivals in terms of the virtues involved in theory choice, and I conclude that because there are no scientific reasons for preferring such a composite-free theory, composites are indispensable for our best scientific theories, and we would need other, non-scientific reasons for rejecting them. In Chapter 4, I raise objections to a debunking argument put forth by the cognitive scientist Donald Hoffman and others, based on Hoffman’s Interface Theory of Perception. Appealing to experimental results in evolutionary game theory, Hoffman argues that our perceptual faculties evolved to guide fitness-enhancing behavior without giving us veridical perceptions of ordinary objects, spacetime, or causal interactions. I show that Hoffman’s argument is self-defeating in a similar manner to what I described in Chapter 1, and his attempts to get around this problem by appealing to a substrate-neutral Universal Darwinism that does not assume the existence of physical objects leads to a fatal dilemma.