It is often said that Leonardo drew so well because he knew about things; it is truer to say that he knew about things because he drew so well.

We can hardly imagine a state of mind in which all material objects were regarded as symbols of spirtual truths or episodes in sacred history. Yet, unless we make this effort of imagination, Medieval art is largely incomprehensible.

Changes in the structure of society are not brought about solely by massive engines of doctrine. The first flash of insight which persuades human beings to change their basic assumptions is usually contained in a few phrases.

You have no idea what portrait painters suffer from the vanity of their sitters.

Gargoyles were the complement to saints; Leonardo's caricatures were complementary to his untiring search for ideal beauty. And gargoyles were the expression of all the passions, the animal forces, the Caliban gruntings and groanings which are left in human nature when the divine has been poured away. Leonardo was less concerned than his Gothic predecessors with the ethereal parts of our nature, and so his caricatures, in their expression of passionate energy, merge imperceptibly into the heroic.

In time of war all countries behave equally badly, because the power of action is handed over to stupid and obstinate men.

Racial prejudices are indication of a disturbed and potentially unstable society.