- Man has always hoped to survive his bodily death, and it is a central tenet of many religions that such survival is a reality. It has been supposed by many that one form such survival might take is reincarnation in another body. Subscribers to this view include Pythagoras, Plato sometimes, and a large number of Eastern thinkers. Other thinkers have, of course, disputed that reincarnation is a fact, and some have even denied that it is a possibility. But seldom has it been claimed by its opponents that reincarnation is a logical impossibility.
- This, however, is the central contention of a recent article - "MacIntosh (J.J.) - Reincarnation and Relativized Identity". Reincarnation, Macintosh maintains, is a logical impossibility because '[g]iven only two very simple necessary truths about identity, plus elementary first-order modal logic1, we can show that reincarnation is impossible'. Anyone who denies this 'must reject one of the following: propositional logic, elementary modal logic2, the reflexivity of identity or modal3 substitution in Leibniz's Law4'.
- The particular logical truth with which, Macintosh claims, the possibility of reincarnation is in conflict is the principle of the necessity of identity, that if a = b then necessarily, a = b. Proofs of this principle are familiar to philosophers and logicians and Macintosh gives one in his article.
- I shall not be disputing the necessity of identity in what follows. However, I shall be disputing Macintosh's claim that the necessity of identity rules out the possibility of reincarnation. As we shall see, there are broadly two lines of thought to follow for one who wishes to maintain, consistently with the necessity of identity, the possibility of reincarnation:
- One line is to develop a theory of personal identity in terms of psychological continuity5 and/or connectedness which takes a ' best candidate ' form and to reject a principle I shall refer to as 'the Only x and y principle'.
- The other line is to accept the Only x and y principle, but still to maintain that psychological continuity6 provides a sufficient ground for identity. A proponent of this second line must endorse what I shall refer to as 'the multiple occupancy view' of certain situations described in the philosophical literature on personal identity.
- Both of these lines of thought have been well-developed in the philosophical literature on personal identity and each has eminent defenders.
Each line has certain implausibilities attaching to it, but neither line requires its proponents to reject the necessity of identity. Macintosh's argument is thus mistaken.
- The first line of thought is defended by, for example, Shoemaker, Parfit7 and Nozick, whilst
- The second is defended by David Lewis and John Perry.
Reply to "MacIntosh (J.J.) - Reincarnation and Relativized Identity".
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