But nothing can continue to give us uninterrupted pleasure, because our nature is not simple, but contains a second element which makes us mortal beings; 211 so that if the one element be active in any way, this is contrary to the nature of the other element, but when the two elements are in equilibrium, what we do seems neither painful nor pleasant; for if there were a being whose nature were simple, the same activity would be always most pleasant to him. And on this account God always enjoys one simple pleasure; for besides the activity of movement, there is also activity without movement, and rest admits of truer pleasure than motion. But change is “the sweetest of all things,” as the poet says, because of a certain badness in us: for just as it is the bad man who is especially apt to change, so is it the bad nature that needs change; for it is neither simple nor good.

We have now considered continence and incontinence, and pleasure and pain, and have explained what each is, and how some of them are good and some bad. It remains to consider friendship.