The part always has a tendency to reunite with its whole in order to escape from its imperfection.

One day the world will look upon research upon animals as it now looks upon research on human beings.

Therefore, O students, study mathematics and do not build without foundations.

Whoever does not respect life, does not deserve it.

Nothing can be loved or hated unless it is first known.

Let the painter composing narrative pictures take pleasure in wealth and variety, and avoid repeating any part that occurs in it, so that the uniqueness and abundance attract people to it and delight the eye of the observer. I say that a narrative painting requires (depending on the scene), wherever the eye falls, a mixture of men of diverse appearances, of diverse ages and dress, combined together with women, children, dogs, horses, buildings, fields, and hills.

We might say that the earth has the spirit of growth; that its flesh is the soil.