Evaluating the evidence for multiple realization

Thomas W. Polger

pp. 457-472

in: Kenneth Aizawa, John Bickle (eds), Neuroscience and its philosophy, Synthese 167 (3), 2009.

Abstract

The belief that mental states are multiply realized is now nearly universal among philosophers, as is the belief that this fact decisively refutes the identity theory. I argue that the empirical support for multiple realization does not justify the confidence that has been placed in it. In order for multiple realization of mental states to be an objection to the identity theory, the neurological differences among pains, for example, must be such as to guarantee that they are of distinct neurological kinds. But the phenomena traditionally cited do not provide evidence of that sort of variation. In particular, examples of neural plasticity do not provide such evidence.