A process is a kind of transitional movement — all processes take time, aim at a certain end, and are complete only when that end is attained. Any given part of a process is incomplete and different in kind from the other parts and from the whole. Pleasure, like the acts of seeing and hearing, is something complete (i.e., perfect) at any given moment of its existence; it cannot be improved by duration and is an end in itself. This shows that pleasure cannot be a process or the end of a process. Like sense perception or thought, it is a perfect, indivisible, and self-contained activity.