Our task in this chapter is to investigate in more detail the dualist conception of the soul as an individually existing thing, whose existence is independent of the existence of the body. We shall consider what answers a dualist might give to two related questions: (1) Under what conditions would a particular disembodied soul after my death be my soul? (2) What would fundamentally distinguish different disembodied souls from one another? Question (1) will form the topic of section ii, and question (2) will form the topic of section iii. But since they both in fact involve the concepts of identity and distinctness, we shall begin by trying to elucidate these. There are a number of points and distinctions to be introduced. Some of them may seem insignificant, but will later turn out to be of the highest importance. (Indeed our ultimate objective will be to construct, in section iii, a proof of the non-existence of the soul.)
(A) Qualitative vs Numerical Identity
Notice to begin with that there are two very different kinds of use of the words ‘same’ and ‘identical’. Thus the question ‘Is this the same car as was involved in the robbery?’ is easily seen to be ambiguous. Is it being asked whether the car in question is similar to (is of exactly the same kind as) the one which was involved in the robbery? Or is it being asked whether it is the very same car? I propose to use the terms ‘qualitative identity’ (or ‘qualitative sameness’) and ‘numerical identity’ (or ‘numerical sameness’) to mark this distinction.