Abstract

Since antiquity, philosophers have struggled to describe the instant of change in continuous time in a way that is both consistent with classical logic and also objective rather than arbitrary. A particularly important version of this problem arises, I argue, for substantial change, that is, any case in which a metaphysical substance comes into or goes out of existence. I then offer and defend an analysis of the instant of substantial change in continuous time that is consistent with classical logic and objective rather than arbitrary. My key assumption is that, necessarily, every substance ages at every instant at which it exists, from which I conclude that no substance has a first or a last instant of its existence if time is continuous. I also suggest that my solution offers some support for endurantism about substances.