In his 1971 paper “Personal Identity”, Derek Parfit posits that it is possible and indeed desirable to free important questions from presuppositions about personal identity without losing all that matters. In working out how to do so, Parfit comes to the conclusion that “the question about identity has no importance” (Parfit, 1971, p. 4.2:3). In this essay, I will attempt to show that Parfit’s thesis is a valid one, with positive implications for human behaviour. The first section of the essay will examine the thesis in further detail and the second will assess how Parfit’s claims fare in the face of criticism.
Problems of personal identity generally involve questions about what makes ...view middle of the document...
Option 2 seems equally as unlikely. How do we decide if A lives on as B or C when each half of A’s brain is exactly similar? Both B and C have equally good reasons for claiming to survive as A so there is no non-arbitrary way to make a distinction between them.
Option 3 now appears to be the most plausible, but only, argues Parfit, if we give up the language of identity. If we do not, A is identical with both B and C. This means that B and C are also identical with each other, which violates the Transitivity Requirement. However, if we abandon the language of identity altogether, we can claim that A survives as B and C without claiming that A is B and C. A’s important psychological connections have been maintained in both B and C, without A being identical to B and C. It is important that we do not confuse survival with identity.
Parfit uses this division case to show that “everything that matters in ordinary survival (or nearly everything), therefore, is preserved in fission, despite the fact that the identity relation is not” (Shoemaker, 2014). What matters in survival need not be one-one.
Furthermore, Parfit uses the concept of fusion to show us that what does matter in survival can be a matter of degree. When A fuses together with B, only some (not all) of A’s characteristics and desires survive. This is also the case with B. We cannot say that A and B have failed to survive, nor can we say that each has survived completely intact. Unlike identity, what matters in survival is not all-or-nothing.
Q-Memory and Psychological Connectedness
Parfit has now shown us that what matters in survival need not be all-or-nothing or one-one. Identity is both all-or-nothing and one-one. Therefore, what matters in survival cannot be identity.
Parfit concedes that because identity is a one-one relation, there is indeed ground for speaking of identity where the relation of psychological continuity is also one-one. But where psychological continuity takes a “one-many or branching form” (Parfit, 1971, p. 4.2:7), we should abandon the language of identity. Therefore, for cases in which we are unable to speak of identity (because the psychological continuity relation is not one-one), psychological continuity will be just as important as identity.
The problem with psychological continuity, however, is that many of the relations involved (including memory relations) appear to presuppose identity. Parfit attempts to avoid this charge of circularity by using the concept of q-memory. Q-memories do not presume that the person having the q-memory and the person who actually had the experience are the same person, unlike ordinary memories which do presuppose identity. Parfit applies this same redesription to other relations of psychological continuity such as intention and responsibility.
Parfit returns to the idea of the importance of the psychological continuity relation in survival to introduce an even more important relation- psychological...