A wise man whispers to me that the pleasures of the wise are true and pure; all others are a shadow only.

Let us examine this: Is not pleasure opposed to pain, and is there not a mean state which is neither?
When a man is sick, nothing is more pleasant to him than health.

But this he never found out while he was well.

In pain he desires only to cease from pain; on the other hand, when he is in an ecstasy of pleasure, rest is painful to him.

Thus rest or cessation is both pleasure and pain.