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.
Raphael Mengs, the painter, was an intimate friend of Winckelmann and associated himself with him in his search for a true definition of the beautiful. His ideas were generally in accordance with those of Winckelmann. He defines beauty as "the visible idea of perfection, which is to perfection what the visible is to the mathematical point." He falls under the influence of the argument from design. The Creator has ordained the multiplicity of beauties. Things are beautiful according to our ideas of them, and these ideas come from the Creator. Thus each beautiful thing has its own type, and a child would appear ugly if it resembled a man. He adds to his remarks in this sense: "As the diamond is alone perfect among stones, gold among metals, and man among living creatures, so there is distinction in each species, and but little is perfect." In his _Dreams of Beauty_, he looks upon beauty as "an intermediate disposition," which contains a part of perfection and a part of the agreeable, and forms a _tertium quid_, which differs from the other two and deserves a special name. He names four sources of the art of painting: beauty, significant or expressive character, harmony, and colouring. The first of these he finds among the ancients, the second with Raphael, the third with Correggio, the fourth with Titian. Mengs does not succeed in rising above this empiricism of the studio, save to declaim about the beauty of nature, virtue, forms, and proportions, and indeed everything, including the First Cause, which is the most beautiful of all.