Functionalism and Personal Identity
Fuller (Gary)
Source: Personalist Forum 8, #1 Supplement, 1992, 133-143
Paper - Abstract

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Philosophers Index Abstract

  1. What is the relation between functionalist accounts of mind and theories of personal identity?
  2. Sidney Shoemaker has suggested that functionalism does have implications for personal identity and that what it implies is a version of the psychological continuity1 theory of personal identity.
  3. I shall examine Shoemaker's interesting suggestion and argue that it fails.
  4. Functionalism, as a theory about the nature of mental states, has few interesting ramification for personal identity and does not favor a psychological theory over a physical theory.

Author’s Introduction
  1. Persons persist, or survive, over time. One of the central philosophical problems about persons, known among philosophers in the analytical tradition as the problem of personal identity, is that of saying what it is for a person to persist, or survive. The problem is to explain what personal identity involves, what constitutes personal identity. Despite recent interest among English-speaking thinkers in a much broader range of philosophical questions about persons than the traditional ones, the problem of personal identity remains central and will not go away.
  2. As in many areas in philosophy, the problem of personal identity is driven by examples. Two of the most important examples are those of amnesia and teleportation. Can a person survive the loss of all the experiential memories of her past life; or, more extreme, what about cases of total amnesia, brain-zap cases, in which as the result of a severe shock what is obliterated are all psychological features that are the result of learning and experience over the years? (See "Shoemaker (Sydney) - Personal Identity: a Materialist Account", pp. 86-88) Can a person survive the process, recently discussed by Parfit2 and others, of teleportation, in which she is beamed down from, say, the spaceship Enterprise to a nearby planet?
  3. For some time now, the main competitor theories of personal identity have been the psychological theory and the physical theory, although there are still a few thinkers, such as Swinburne, who hold something like a Cartesian ego, or soul-theory, in which personal identity is irreducible. The psychological theory and its main competitor, however, have in recent years become rather sophisticated. Certainly, few philosophers, if any, would accept a straightforward Lockean memory-theory or a simple body-theory. Recent psychological theorists, such as Parfit3 and Shoemaker, hold that much psychological continuity4 is required for personal identity, but are very tolerant about the kind of causal mechanism which explains the continuity. Physical theorists, such as Williams, Wiggins, and Unger, require much less psychological continuity5 but hold that this must be supported by the persistence of something like a body, or at least a brain.
  4. There really is no consensus on which of the two general accounts, the psychological or the physical, is right. And there seems to be no substitute for hard, honest toil in finding the answer6. It would be nice if someone could come up with a clear, simple argument that would settle the matter on one side or the other.
  5. One thing, however, on which everyone seems agreed is that the traditional mind/body problem has little relevance for the problem of personal identity. Psychological theorists of personal identity can of course be materialists and some physical theorists of personal identity may be mind/body dualists. Even within the materialist camp it is hard to see how one’s mind/body position, whether behaviorist, identity theorist, or functionalist, has any important ramifications for personal identity.
  6. Sydney Shoemaker is an exception. He thinks that at least one mind-body position, namely functionalism, does make a difference for personal identity. Indeed, he thinks that functionalism solves our problem about personal identity in favor of the psychological theory. His most explicit statement and elaboration of this view occurs in his contribution to "Shoemaker (Sydney) & Swinburne (Richard) - Personal Identity". Here are two relevant quotes:
    • What I propose … is to consider a widely held … theory about the nature of mental states, [namely, functionalism], a theory that has been held on grounds having nothing to do with personal identity, and to see what that theory implies about the nature of personal identity. What it implies seems to me to be a version of the psychological continuity7 view, and one which puts the notion of an "appropriate causal connection" in a new and interesting light. (91, my italics)
    • … there is, on the functionalist view, a very intimate connection between the question 'What is the nature of the various mental states?' and the question 'How must different mental states be causally connected in order to be "co-personal", i.e., to belong to one and the same person?' (948)
  7. If Shoemaker is right, this will be quite exciting. Without much work we will have found the simple argument we were looking for. Of course, the soundness of the argument will depend on the correctness of functionalism as an account of mental states. Luckily, however, the argument will depend only on the most general claims of functionalism that mental states are abstract, relational, and causal9.
  8. In what follows I shall examine seriously, and with some sympathy, Shoemaker's suggestion that functionalism implies (a version of) the psychological theory of personal identity. I shall argue that unfortunately Shoemaker's suggestion is false. Our initial reaction that mind-body theories are mostly irrelevant to personal identity was right. Functionalism about the nature of mental states, and even about the nature of persons, has few interesting ramifications for personal identity and certainly does not imply Shoemaker's version, or any version for that matter, of the psychological theory.
  9. The paper is divided into four sections.
    1. I give a brief account of functionalism and of the version of the psychological theory which Shoemaker favors and thinks is implied by functionalism.
    2. The notion of 'functional continuity' is introduced, and Shoemaker's thesis is reinterpreted as the claim that functionalism implies a functional continuity account of personal identity.
    3. I consider and reject the claim that functionalism implies that functional continuity is necessary for personal identity, and
    4. I consider and reject the corresponding sufficiency claim.



In-Page Footnotes

Footnote 6: I am thinking, for example, of detailed, and at times somewhat tedious, workings through of the great variety of cases involving change, removal, and replacement of parts of stones, cars, trees, computers, and, of course, brains.

Footnote 8: Shoemaker also thinks that functionalism has implications for the problem of the synchronic unity of mind as well as for the problem of personal identity over time (the diachronic problem), but I shall be concentrating here only on the latter problem.

Footnote 9: At least as part of an account of intentional mental states, these general claims are compatible even with many non-individualistic accounts of the content of mental states, and would be agreed upon by the majority of contemporary philosophers writing about these issues, with some exceptions such as Searle and perhaps Wiggins.


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