In 1906, the French savant Pierre Duhem published a three-volume work on Leonardo as scientist under the innocuous title Études sur Leonard de Vinci. It was the work’s subtitle that struck a note of novelty: Ceux qu’il a lus et ceux qui l’ont lu (“Those he read and those who read him”). Leonardo, then as now, was celebrated as an artist, an inventor, an engineer, a universal wizard and, to appropriate the title of the current exhibition at the Metropolitan Museum of Art (until March 30), a master draftsman. One would take it for granted that he was literate, but how interesting could it be to know what his reading list was, or on whose list of required reading his writings appeared? Duhem’s book, however, was really a profound contribution to the history of science. It analyzed Leonardo’s debts to medieval scientists like John Buridan, Albert of Saxony and Nicolas Oresme, and then went on to the scientific impact of Leonardo’s writings on subsequent investigators. It was no part of Duhem’s intention to diminish Leonardo’s originality as a scientist but rather to redeem the Middle Ages as a chapter in the history of scientific thought. It had been a historical commonplace to view the long interval between Archimedes and Galileo as a period of unrelieved ignorance and superstition. Duhem, a distinguished physicist and a great philosopher of science, was also a believing Catholic, and it was his aim to prove that Catholicism had played an importantly supportive role in the development of knowledge. He showed that Leonardo was carrying forward programs of research in mathematics, mechanics and biological science that had a long and remarkable medieval development. And he demonstrated that Leonardo, far from jotting down his observations on whatever came along, had a systematic scientific agenda that bears comparison with that of such later thinkers as Descartes, and that his various treatises contributed to research carried on well after his death.
The rebirth implied by the concept of the Renaissance had reference to classical learning. It was more or less self-promotion that demanded an interval of darkness between the fall of Rome and the rebirth of its culture in Tuscany. What Duhem established was that Leonardo mediated between the great investigators of the medieval period and those that were to come after him. And to a very large extent, one can construct a Duhemian picture of Leonardo’s place in the history of art–a parallel narrative which shows that even where Leonardo was most original, he was also in effect in conversation with his predecessors, and his successors in conversation with him. Like Duhem’s, this would not have the aim of diminishing his achievement as an artist but, since art comes from art as much as science comes from science, explaining it historically. Indeed, the Met’s exhibition has exactly this format. One could almost paraphrase Duhem’s subtitle: Ceux qu’il a vus, et ceux qui l’ont vu. The show begins with those whom Leonardo learned from, and ends with those who learned from him.
There is little doubt that it is valuable to situate Leonardo in the history of art in this way. Consider the article on Leonardo in the celebrated eleventh edition of the Encyclopedia Britannica, by then-Slade Professor of Fine Arts at Cambridge, Sidney Colvin. “By his own instincts he was an exclusive student of nature…. He was the first painter to recognize the play of light and shade as among the most significant and attractive of the world’s appearances.” But just as many of Leonardo’s observations were intended to confirm ideas he acquired from Albert of Saxony and others, the “play of light and shade” that he made his own was taught him by Andrea del Verrocchio, to whom he was apprenticed. So it is entirely appropriate that the exhibition begin with a drawing of Verrocchio’s, which shows that sfumato–a technique for depicting the way light and dark softly and almost indiscernibly grade into each other, convey the roundedness of a form–was already a matter of studio practice when Leonardo was in his teens. It was thus not something he learned by studying nature but that he acquired from his master. It could be true that the way it was used by Leonardo stamped him as a pupil of Verrocchio. But sfumato was not a workshop mannerism–it was a discovery, like perspective. It was a way of showing the shape in three dimensions of volumes through light and shadow, just as perspective is a way of showing how objects recede in space. The decision to present things in these terms was one of the marks of the Renaissance. To show things the way the eye sees them defined the artistic culture in which Leonardo worked. But it is not a matter of culture that the eye sees the world the way it does. That, as we say, is hard-wired. Because it was a cultural agenda to “conquer appearance,” the history of art in the Renaissance is like the history of science when viewed as a progress. “In early modern Europe,” the philosophical historian of science Thomas Kuhn wrote, “painting was regarded as the cumulative discipline.” That medieval art did not conform to this agenda was counted by Renaissance writers like Vasari as palpable evidence that it belonged to the Dark Ages.