Since pleasure and pain are in some way the causes of virtue and vice, it is necessary to determine the nature of pleasure. There are three popular views on the subject:
- That all pleasures are bad, either in themselves or incidentally, and that pleasure and the good by definition cannot be identical.
- That some pleasures are good, but most are bad (a view expressed by Plato in the Philebus).
- That even if all pleasures are good, it is impossible for pleasure to be the highest good (another view expressed by Plato in the Philebus).