The difference between what ...

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.
 See image
 Kenneth Clark

Quotes from the same author

Great works of art can be produced in barbarous societies - in fact the very narrowness of primitive society gives their ornamental art a peculiar concentration and vitality. At some time in the ninth century one could have looked down the Seine and seen the prow of a Viking ship coming up the river. Looked at today in the British Museum, it is a powerful work of art; but to the mother of a family trying to settle down in her little hut, it would have seemed less agreeable - as menacing to her civilisation as the periscope of a nuclear submarine.
 See image
 Kenneth Clark
Just as a classical dancer repeats the same movements again and again, in order to achieve a greater perfection of line and balance, so Degas repeats the same motifs - it was one of the things that gave him so much sympathy with dancers.
 See image
 Kenneth Clark
No nude, however abstract, should fail to arouse in the spectator some vestige of erotic feeling, even if it be only the faintest shadow - and if it does not do so it is bad art and false morals.
 See image
 Kenneth Clark
No nude, however abstract, should fail to arouse in the spectator some vestige of erotic feeling... The desire to grasp and be united with another human is so fundamental a part of our nature that our judgement of what is known as 'pure form' is inevitably influenced by it, and one of the difficulties of the nude as a subject for art is that these instincts cannot be hidden.
 See image
 Kenneth Clark
Ingres was one of those artists to whom the outline was something sacred and magical, and the reason is that it was the means of reconciling the major conflict in his art, the conflict between abstraction and sensibility.
 See image
 Kenneth Clark