All thoughts start from emotions.

One has no right to love or hate anything if one has not acquired a thorough knowledge of its nature. Great love springs from great knowledge of the beloved object, and if you know it but little you will be able to love it only a little or not at all.

First study the science, and then practice the art which is born of that science.

Mechanics is the paradise of the mathematical sciences because by means of it one comes to the fruits of mathematics.

Painting is poetry that is seen rather than felt, and poetry is painting that is felt rather than seen.

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.

Every action needs to be prompted by a motive.