In fact, whatever exists in the universe, in essence, in appearance, in the imagination, the painter has first in his mind and then in his hands ... it lies in his power to create them . . .

Even the richest soil, if left uncultivated will produce the rankest weeds.

A clever man without wisdom is like a beautiful flower without fragrance.

There are three classes of people: those who see, those who see when they are shown, those who do not see.

Of several bodies, all equally large and equally distant, that which is most brightly illuminated will appear to the eye nearest and largest.

Avoid the precepts of those thinkers whose reasoning is not confirmed by experience.

The vine that has grown old on an old tree falls with the ruin of that tree, and through that bad companionship must perish with it.