on Persistence

Next, persistence through time. I take the view that nothing endures identically through time. (Except universals, if such there be; their loci would coincide with relations of qualitative match, would indeed constitute these relations, so they would commit no violations of Humean Supervenience.) Persisting particulars consist of temporal parts, united by various kinds of continuity. To the extent that the continuity is spatiotemporal and qualitative, of course it supervenes upon the arrangement of qualities. But the continuity that often matters most is causal continuity: the thing stays more or less the same because of the way its later temporal parts depend causally for their existence and character on the ones just before. So the spatiotemporal boundaries of persisting things, for example people, can supervene on the arrangement of qualities, provided that causation does. (Philosophical Papers, volume II, xiii)