Personal Identity and the Extended Mind

In this dissertation, I argue that the Extended Mind hypothesis is correct, that its truth suggests a Parfitian view of personal identity, and that psychological views of personal identity in general are committed to some version of the Extended Mind hypothesis.;In the course of arguing for these views, I develop some new ideas about the distinction between original and derived content, as well as the Chinese Room thought experiment. Specifically, I argue that most content is original, not derived as most would think. In fact I go so far as to argue that the act of reading text in one's native language, with facility, counts as a use of the content of that text as original rather than derived. Regarding the Chinese Room thought experiment, I argue that neither the person in the Chinese Room nor the Chinese Room itself are computationally equivalent to a computer following a program for understanding Chinese. This means almost all discussion over the thought experiment gets off on the wrong foot from the beginning.;A recurring theme throughout the work involves the question of whether concepts with no causal implications can serve as useful distinction markers in the pursuit of scientific explanations. I argue that they cannot, but this argument goes against the majority view. The imaginary creature Swampman is often used as an illustration of the opposite view--that causally identical entities can nevertheless be distinct according to a good scientific ontology. For this reason, I spend a chapter talking about Swampman, arguing that though the majority view is correct in a way, its implications should be taken to have only epistemological import, not ontological import. Swampman is in fact of the same ontological type as a human being, but should any good biologist knowingly encounter Swampman in the wild, the biologist must treat him as though he were not human. This is not a very serious matter, since Swampman is merely an imaginary creature. For real creatures in the real world, the epistemological distinctions and ontological distinctions cut nature identically.