Conventional nudes based on classical originals could bear no burden of thought or inner life without losing their formal completeness.

Fine colour implies a unified relationship, in which each part is subordinate to the whole, and the transitions between them are felt to be as precious and beautiful as the colours themselves. In fact, the colours themselves must be continuously modified and broken as part of the transition.

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.

Only the bad artists of the nineteenth century were frightened by the invention of photography; the good ones all welcomed it and used it. Degas liked it not only because it provided an accurate record, but because the snapshot showed him a means of escape from the classical rules of design. Through it he learnt to make a composition without the use of formal symmetry.

The difference between what we see and a sheet of white paper with a few thin lines on it is very great. Yet this abstraction is one which we seem to have adopted almost instinctively at an early stage in our development, not only in Neolithic graffiti but in early Egyptian drawings. And in spite of its abstract character, the outline is responsive to the least tremor of sensibility.

Leonardo is the Hamlet of art history whom each of us must recreate for himself.

Over and above the political, economic, sociological, and international implications of racial prejudices, their major significance is that they place unnecessary burdens upon human beings.