In his Phaedo, he sought to avoid this perishability, which would be a true annihilation, by attempting to prove that a simple being cannot cease to be at all because, since it cannot be diminished and thus lose more and more of its existence, and so be gradually transformed into nothing (since it has no parts and thus no plurality in itself), there would be no time at all between a moment in which it is and another moment in which it is not, which is impossible.