The label “pious” here means all those of medieval spirit. In the eyes of the grand master, the old beauty became a concern of the little and the weak. But not all agreed. To Dürer and Quinten Metsys and to Jan van Scorel, who is reputed to have kissed The Lamb of God, this old art is by no means dead. But in this instance Michelangelo precisely represents the Renaissance. His charges against Flemish art are exactly against the essential features of the late medieval mind: the vehement sentimentality, the inclination to regard every detail as an independent entity, to be totally absorbed by the variety and color of the seen object. The new Renaissance perception of art and life resists this. This new perception is, as always, only accessible to us at the expense of temporarily turning a blind eye on past beauty or truth.
An awareness of a conscious aesthetic appreciation and a verbal expression for it developed rather late. Admirers of art during the fifteenth century have at their disposal only the manner of expression we could expect of a burgher, caught in the instance of astonishment, for whom the very idea of artistic beauty has not yet dawned. Whenever the beauty of art penetrates his mind with its radiance and thrills him, he immediately converts the emotion either into a sense of being filled with God or into an awareness of the joy of life.
Denis the Carthusian wrote a treatise De venustate mundi et pulchritudine Dei. The title already tells us that true beauty is only for God to know; the world can only be venustus: pretty, lovely. The beauties of created things, he says, are only the outpouring of the highest beauty; a creation is deemed beautiful only insofar as it shares in the beauty of divinity and, by virtue of this fact, comes somewhat to resemble the highest. On the basis of this far-ranging and elevated aesthetic theory, for which Denis relies on the Pseudo-Areopagite, Augustine, Hugo of St. Victor, and Alexander of Hales, a pure analysis of all beauty could have been built. But the mind of the fifteenth century fails completely to meet the challenge. Denis even borrows his examples of earthly beauty, a leaf, the sea and its changing colors, the restless sea, from the fine minds of his twelfth-century predecessors, Richard and Hugo, members of the monastery of St. Victor. Whenever he is intent on an analysis of beauty itself, he remains entirely on the surface. Herbs are beautiful because they are green, stones because they sparkle, the human body, as well as the dromedary and the camel, because it is suited to its purpose. The world is beautiful because it is long and wide, the heavenly bodies because they are round and bright. In mountains we admire size; in rivers, length; in fields and forests, expanse; and in the earth itself, its immeasurable quantity.
Medieval thought always traces the idea of beauty back to the concepts of perfection, proportion, and splendor. “Nam ad pulchritudinem,” says Thomas Aquinas, “tria requiruntur. Primo quidem integritas sive perfectio: quae enim diminuta sunt, hoc ipso turpis sunt. Et debita proportio sive consonantia. Et iterum claritas: unde quae habent colorem nitidum, pulchra esse dicuntur.” Denis attempts to apply a similar yardstick. The results are somewhat clumsy; applied aesthetics are always a miserable matter. No wonder that the mind is incapable of dwelling on earthly beauty when tackling such an abstraction as the notion of beauty itself. Denis always veers to unseen beauty whenever he undertakes to describe the beautiful: to the beauty of the angels and the empyrean; or he seeks to find it in abstract things: the beauty of life is the conduct of life under the guidance and command of divine law, freed from the ugliness of sin. He does not speak of the beauty of art, not to mention that of music, which he could be most likely expected to have become aware of as having an aesthetic value in its own right.