Panofsky, Galileo As A Critic Of The Arts, the original, not the shortened one. The first section.

footnotes—which take up almost as much space as the text—stripped for simplicity, though they're no less fun to read. Greek words marked (...)

The greek passion for debate, legal or not, produced, as early as the fifth century B.C., a peculiar genre of literature, called (... ) in Greek and altercatio, concertatio, dialogus, disputatio or conflictus in Latin; in English, something like "contest" or "debate" would seem to be the most appropriate equivalent. What we witness is, as a rule, not an internecine battle between absolute good and absolute evil (as in the struggle between the Virtues and the Vices, Reason and Lust, Faith and Heresy); rather it is a competition for superiority between two—or, occasionally, more than two— relative values, a competition that may end with a reasonable compromise or even a happy reconciliation.

The contestants may be Virtue and Pleasure but also The Cook and The Pastry Baker, Homer and Hesiod, or Poetry and History but also Lentils Boiled Whole and Lentils Pureed. And in the Hellenistic age, when Plato's theory of ideas was reinterpreted so as to glorify rather than disparage the "imitative arts", the arena was entered by Painting and Sculpture. In Lucian's Dream, Sculpture (...) wages, but loses, a battle against Refined Culture (...); in Dio Chrysostom’s Olympic, Phidias, claiming for sculpture the ”power of the symbol” (...) and the ability to produce ”what cannot be compared to any mortal human being”, wins an imaginary argument with Homer; and in the Introduction to Philostratus’ Imagines we hear the echo of a debate between Sculpture and Painting, the author deciding in favor of the latter. 

In the Western Middle Ages, contest literature was passionately cultivated  in Latin as well as in the vernacular languages, and the number and kind of contestants were varied ad infinitum. Wine competes with Water or Beer; Winter with Summer; The Mountain with The Valley; The Swan with The Crow; The Cleric with the Layman, Peasant or Knight; Worldly Glory with Pious Renunciation; Fortune with Philosophy; The Body with The Soul. Even the case of natural love vs. what the State Department calls "deviationism"—outlined in Plato's Phaedrus and circumstantially developed, from opposite points of view, by Plutarch and Lucian—was kept alive and was amusingly restated in a rhymed debate between Helen of Troy (supported by Nature) and Ganymede (supported by Philology), which ends with the betrothal of the disputants. However, what disappeared from the scene of mediaeval contest literature were the visual arts. Once painting and sculpture had been demoted to the status of artes mechanicae (which adjective was held to derive from Latin moechus, bastard, rather than from Greek (...), their rivalry with each other was no longer of interest while the possibility of their competing with their aristocratic sisters, the liberal arts, was excluded on principle: the Bataille des Sept Arts was a tournament in which mere burghers were not permitted to participate.

It was not until about 1400—when Brunelleschi and Ghiberti competed for the bronze doors of the Baptistry, when Donatello was an apprentice, and when Masaccio was born—that Cennino Cennini came forward with the contention that painting had a legitimate claim to recognition as a liberal art. His reasoning was rather naive: the painter, he says, is equal to the poet in that he can produce imaginary beings as well as reproduce real ones. But his position, expressing a fundamental change in attitude, came to be generally accepted. The privilege obtained by painting was gradually extended to what was later to be called the "Fine Arts"; and for a sixteenth century thinker  it was, again, more natural to illustrate the meaning of Plato's ideas by "that image of a perfectly beautiful body" which lives in the mind of an artist than by the archetype impressed upon the mind of a philosopher.

No sooner, however, had painting and sculpture been promoted to the rank of Art with a capital "A" than they began to fight each other for superiority. In the North, not as yet inclined to theorize about the arts, a certain rivalry between painting and sculpture may reflect itself in those simulated statues which challenge the genuine productions of sculpture in the altarpieces of the Master of Flémalle, Jan van Eyck and their followers. In Italy, it came into the open about 1430. Leone Battista Alberti, the first art theorist in the full sense of the word, clearly alludes to it when he suggests that sculpture and painting, though different in means and aims, were equal in rank and should keep the peace,  and thereafter the competition between the two sister arts remained the favorite topic of contest literature in many lands and for several centuries. A climax was reached in Leonardo da Vinci's "Paragone" where painting carries the offensive deep into the territory of the liberal arts, claiming to be superior not only to sculpture but also to music and poetry. And by the middle of the sixteenth century the discussion about the relative merits of painting and sculpture, by now a kind of intellectual pastime, even gave rise to what is perhaps the earliest public opinion poll: in 1546, preparatory to two lectures published three years later, a Florentine humanist, Benedetto Varchi, elicited statements from a great number of important artists, including  Michelangelo, Benvenuto Cellini and Pontormo, each of them loyally defending his own profession. 

This "Paragone" literature has some importance in that it fomented such notions as "sculptural" and "pictorial," "volume" and "space," "one view composition" and "multiview composition," notions which, when the quarrel for superiority had subsided in favor of a calm appraisal of possibilities and limitations, were to become the basic concepts of what we call "stylistic analysis." But on the whole texts of this kind cannot be said to make inspiring reading. Few l~ter writers went beyond the arguments put forward by Leonardo da Vinci, adopting and, very rarely, amplifying them when they were painters or friends of painting, attempting to refute them when they were sculptors or friends of sculpture. There is, however, one glorious exception: a letter of no less illustrious an author than Galileo Galilei.