Is There a Problem About Persistence?

Abstract

In that little classic 'Identity, Ostension and Hypostasis' W. V. 0. Quine introduces the problem of identity over time in this way: 'Undergoing change as I do, how can I be said to continue to be myself? Considering that a complete replacement of my material substance takes place every few years, how can I be said to continue to be I for more than such a period at best? Quine goes on to mention Heraclitus's allegedly parallel problem regarding rivers-how can you step in the same river twice if new waters are ever flowing upon you? The real problem here is not the problem these questions pose but the problem of exhibiting and justifying some philosophical problematic which explains why we should not rest content with the most obvious and dismissive answers to these questions, e.g. 'It is just of the nature of persisting human beings and rivers that they are constituted by different matter at different times, not wholly and abruptly different matter of course, but not too different matter as between not too distant times'. Quine's questions seem answerable by such humdrum empirical observations. How can they be the occasion for high theory? (By the way, if one has a taste for even a little theory, one might worry how there can be-as Quine's second question suggests-a problem about my identity over longish periods involving continuous change, but no problem about my identity over the shorter periods which can be partially overlapped to make up such longish periods.) 'Identity, Ostension and Hypostasis' and subsequent Quinean classics like 'Worlds Away' do develop a problematic of identity over time, one which may be introduced as follows.2 Standing