  The problem can be made sharper by reflection upon the law of the indiscernibility of identicals. If a thing-at-\(t_{1}\) were identical with a thing-at-\(t_{2}\), then they should share all their properties. What sort of identity is it, if not that? But if the properties at different times are incompatible, then a contradiction follows. Because they emphatically took the view that contradictions are never true, the great Buddhist logicians Dharmakirti (C7th CE) and his commentator Dharmottara (C8–9th CE), who had certainly read their Aristotle, deduced that identity over time does not exist (see Scherbatsky (1930) vol 2). This is the Buddhist doctrine of moments, essentially an ontology of instantaneous temporal slices. The doctrine of the momentariness of existence is felicitously in accord with the core Buddhist doctrine of the impermanence of all things. The doctrine of moments might seem to be an unnecessarily strong application of impermanence, certainly unnecessary for soteriological purposes, were it not for the evident strength of the argument in its favour, not to mention its accord with the spacetime ontology of modern physics. On the other hand, it is of course psychologically very difficult to believe that one’s own self, as something genuinely self-identical, has not endured from moment-to-moment in the past. Even so, the thesis of the momentariness of human existence has had a recent defender in Derek Parfit (1984), who asks what sort of principle could unify the temporal stages sufficiently closely to be worth calling identity. He argues that none could, and proposes that internalising the momentariness of our lives has a beneficial effect on how we should face our deaths.