On Alberti's "sign": vision and composition in quattrocento painting - Leon Battista Alberti's commentary 'On Painting'

Alberti's rule of composition places surfaces at the confluence of two key aspects of painting. Surfaces are at once the "prime parts" of the pictorial work and the smallest visible components of the depicted bodies (II.35). These two aspects of the surfaces have a well-established pedigree within Aristotelian philosophy. A passage from Aristotle's On Interpretation (16a4-b25), a required text for a bachelor's degree in fifteenth-century universities, discusses what a "prime part" is in an expressive system.(10) Aristotle explains that words are the prime parts of speech, because they fulfill the function of speech, which is to direct the mind to concepts, while their component parts - that is, syllables - do not. Conversely, two passages from Metaphysics (1041b9-33 and 1043b4-6), a more advanced but also widely read text, describe what a component is. According to Aristotle, components are the material parts out of which things are formed. These components are necessary for the thing to exist, but by themselves, detached from the composite whole, the components do not fulfill the function of the thing that they compose. He gives as examples a syllable, a house, and flesh. Syllables are composed of letters; houses, of some building material, such as bricks; and flesh, of the material elements (earth, air, water, and fire). If the letters of a syllable, the bricks of a house, or the elements of flesh are separated from one another, the syllable, the house, or the flesh would cease to exist, but the letters, bricks, and elements would remain. Separated from one another, however, letters alone do not serve as the sounds of speech; bricks alone do not provide shelter; and the elements alone do not constitute the flesh of a human being. Only by virtue of being composed do the components fulfill the function of the whole.

By treating composition as a stylistic principle, Baxandall obscures one of Alberti's most remarkable critical insights. None of the various parties to the quattrocento dispute cited by Baxandall questioned the primacy of words in speech. Alberti's definition of composition gives surfaces the same primacy in painting that words have in speech. This analogy between words and surfaces is, to my knowledge, unprecedented and suggests that surfaces are the prime parts of painting for the same reason that words are the prime parts of speech. As Aristotle maintains, words are the prime parts of speech because they fulfill the expressive function of speech, while their component parts - the syllables - do not. If the component parts of bodies are the four elements - earth, air, water, and fire - then the component parts of paintings are the materials that make up its pigments, mediums, grounds, and supports. Yet the surfaces of which Alberti speaks are not the material surfaces of the pictorial work of art (nor the material surfaces of real, natural bodies). Rather, as component parts of depicted bodies, these surfaces are already products of the representational process. For only in the context of a representational work do the material components of painting fulfill their expressive function by taking on the visual qualities of depicted bodies, say, by appearing fleshlike. Conversely, it may properly be said that the artist composes members out of surfaces, bodies out of members, and the completed work out of bodies, only if surfaces are thought somehow to provide the fleshlike material for the members, bodies, and historia. Alberti designates depicted surfaces, not pigments, the "prime parts" of painting because depicted surfaces are the smallest units that fulfill the expressive function of painting, which is directing the eyes and minds of viewers to the depicted objects. Alberti's rule of composition, then, invests depicted surfaces with a visual and logical priority within painting. As the prime units of the pictorial work and the smallest components of the depicted bodies, surfaces are where representation begins. By making composition the focus of his art of painting, Alberti draws attention to, and explains the significance of, this defining feature of Renaissance art.