Anyone who conducts an argument by appealing to authority is not using his intelligence; he is just using his memory.

When you look at a wall spotted with stains...you may discover a resemblance to various landscapes, beautiful with mountains, rivers, rocks, trees. Or again, you may see battles and figures in action, or strange faces and costumes, and an endless variety of objects which you could reduce to complete and well-drawn figures.

The function of muscle is to pull and not to push, except in the case of the genitals and the tongue.

Among the great things which are found among us the existence of Nothing is the greatest.

I abhor the supreme folly of those who blame the disciples of nature in defiance of those masters who were themselves her pupils

Now do you not see that the eye embraces the beauty of the whole world? It counsels and corrects all the arts of mankind... it is the prince of mathematics, and the sciences founded on it are absolutely certain. It has measured the distances and sizes of the stars it has discovered the elements and their location... it has given birth to architecture and to perspective and to the divine art of painting.

The desire to know is natural to good men.