Perspective is nothing more than a rational demonstration applied to the consideration of how objects in front of the eye transmit their image to it, by means of a pyramid of lines. The Pyramid is the name I apply to the lines which, starting from the surface and edges of each object, converge from a distance and meet in a single point.

When that which loves is united to the thing beloved it can rest there; when the burden is laid down it finds rest there. There will be eternal fame also for the inhabitants of that town, constructed and enlarged by him.

Demetrius was wont to say that there was no difference between the words and speech of the unskilled and ignorant and the sounds and rumblings caused by the stomach being full of superfluous wind. This he said, not without reason, for, as he held, it did not in the least matter from what part of them the voice emanated, whether from the lower parts or the mouth, since the one and the other were of equal worth and importance.

Nature is full of infinite causes that have never occurred in experience.

An artist who lacks the power of self-criticism accomplishes but little. It is good if your work stands higher than your own opinion of it; bad if it is on the same level. But it is a great disaster if your work stands lower than your judgment of it.

Learning acquired in youth arrests the evil of old age.

He who cannot establish dominion over himself will have no dominion over others.