Metaphysics of Persistence and Time.
- Change has been a pressing philosophical problem since the ancient Greeks, yet it is one of the most pervasive and undeniable phenomena. On the face of it, change is contradictory. The strict philosophical definition of “identity” as expressed in Leibniz's law is that two objects are identical only if they share all the same properties. The problem of change arises since a thing before a change ha... read mores different properties than the thing after the change. For example, in the morning I was sitting at home, in the afternoon I was standing in the library. In the morning I was a bent shape (since I was sitting) and in the afternoon I was straight shape (since I was standing). Applying Leibniz’s law to this case, it would appear that I am not the same thing in the morning as in the afternoon. This conclusion runs counter to our everyday understanding of change. Worse, the problem generalizes to all cases of change: if x changes, then x is the same identity before and after the change, and x has some property before the change that it lacks after (otherwise there is not really change), but by Leibniz’s law this entails a contradiction. There are two parallel problems of change, the first deals with material objects and the second with persons. In ordinary life, we interact with changing material objects all the time without worry. We treat objects like tables and chairs as things which can survive change, but the problem of change seems to undermine this idea. In regards to other problem of change, the idea that persons service change is essential to our conception of personhood. Jettison the identity of persons over time and then most of the attitudes we take, such as hope, blame, and regret lose their appropriateness. These attitudes only make sense if we think of persons as things which survive change. Submitted in partial fulfillment of the grant requirement of the Tufts Summer Scholars Program.read less