Some pleasures, distinguished from the rest specifically or according to their sources, are to be chosen _per se_ (III.).
He then attempts to define pleasure.

It is something perfect and complete in itself, at each successive moment of time; hence it is not motion, which is at every moment incomplete.

Pleasure is like the act of vision, or a point, or a monad, always complete in itself.

It accompanies every variety of sensible perception, intelligence, and theorizing contemplation.

In each of these faculties, the act is more perfect, according as the subjective element is most perfect, and the object most grand and dignified.