A special faculty is required to appreciate this beauty, which Winckelmann is inclined to call intelligence, or a delicate internal sense, free of all instinctive passions, of pleasure, and of friendship. Since it becomes a question of perceiving something immaterial, Winckelmann banishes colour to a secondary place. True beauty, he says, is that of form, a word which describes lines and contours, as though lines and contours could not also be perceived by the senses, or could appear to the eye without any colour. It is the destiny of error to be obliged to contradict itself, when it does not decide to dwell in a brief aphorism, in order to live as well as may be with facts and concrete problems. The "History" of Winckelmann dealt with historic concrete facts, with which it was necessary to reconcile the idea of a supreme beauty. His admission of the contours of lines and his secondary admission of colours is a compromise. He makes another with regard to the principle of expression. "Since there is no intermediary between pain and pleasure in human nature, and since a human being without these feelings is inconceivable, we must place the human figure in a moment of action and of passion, which is what is termed expression in art." So Winckelmann studied expression after beauty. He makes a third compromise between his one, indivisible, supreme, and constant beauty and individual beauties. Winckelmann preferred the male to the female body as the most complete incarnation of supreme beauty, but he was not able to shut his eyes to the indisputable fact that there also exist beautiful bodies of women and even of animals.