Alteration can therefore be perceived only in substances, and arising or perishing per se cannot be a possible perception unless it concerns merely a determination of that which persists, for it is this very thing that persists that makes possible the representation of the transition from one state into another, and from non being into being, which can therefore be empirically cognized only as changing determinations of that which lastsY If you assume that something simply began to be, then you would have to have a point of time in which it did not exist.