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.

The good painter must paint two things: a person and the essence of his soul.

Wisdom is the daughter of experience

Iron rusts from disuse; water loses its purity from stagnation... even so does inaction sap the vigor of the mind.

...The world wouldn't be the world, without trouble.

Whoever despises the high wisdom of mathematics nourishes himself on delusion and will never still the sophistic sciences whose only product is an eternal uproar.

A luminous body will appear more brilliant in proportion as it is surrounded by deeper shadow.