THE PROBLEM OF CHANGE Things change—I was in my office five minutes ago, and now I’m here. Worse, things change intrinsically: I was standing, now I sit. If I change intrinsically, then my current self is distinguishable from my past self; and by Leibniz law, that identicals are indiscernible, my present self is not identical to my past self. So we now have to find some other relation than ‘=’ to capture the relation between my present and past selves. What is this relation of ‘personal...