Learning acquired in youth arrests the evil of old age.

Just as iron rusts from disuse, and stagnant water putrefies, or when cold turns to ice, so our intellect wastes unless it is kept in use.

The supreme misfortune is when theory outstrips performance

As regards this vice, we read that the peacock is more guilty of it than any other animal. For it is always contemplating the beauty of its tail, which it spreads in the form of a wheel, and by its cries attracts to itself the gaze of the creatures that surround it. And this is the last vice to be conquered.

Avoid the precepts of those thinkers whose reasoning is not confirmed by experience.

You do ill if you praise, but worse if you censure, what you do not understand.

A deaf and dumb person who sees two men in conversation - may nevertheless understand from the attitudes and gestures of the speakers, how well their discussion is getting along.