Free Da Vinci's Ghost by Toby Lester

natural philosophy, he decided, would be resolutely empirical: he would get his hands dirty. The scholastics considered such an approach ignorant and ignoble, but he didn’t care. “They will say ,” he wrote, “that because I have no book learning, I cannot properly express what I desire to treat of. But they do not know that for their exposition my subjects require experience rather than the words of others.”
    It’s not clear exactly how or when Leonardo began thinking this way. But by the time he struck out on his own as an artist he’d already started. In notes that survive from the early 1480s, for example, when testing out a new pen he scribbled variations on the phrase
“Dimmi”
( “Tell me ”). “Tell me … tell me whether … tell me how things are … tell me if there was ever.” These are the tics of an increasingly hungry mind.
    He began asking such questions of others, too. In one note, which dates from about 1481 and is written alongside sketches of a sundial, a pneumatic or hydraulic water clock, and various geometrical figures, he lists eight Florentines whom he seems to want to consult. Of those eight, three have yet to be identified, one is a painter, and the remaining four are men whose areas of expertise hint at the rapidly diversifying range of Leonardo’s curiosities. The first, Carlo Marmocchi, was anastronomer and geographer whose quadrant (or treatise
The Quadrant
) Leonardo noted an interest in; the second, whom Leonardo called Benedetto of the Abacus, was a well-known local mathematician; the third, Paolo dal Pozzo Toscanelli, was one of the great sages of fifteenth-century Florence; and the fourth, Joannes Argyropoulos, was a hugely influential Byzantine scholar who had fled to Italy after the fall of Constantinople in 1453.
    It’s no surprise that Leonardo was drawn to Toscanelli and Argyropoulos. Each was nearing the end of an illustrious life, and both had reputations as men who could teach Leonardo a great deal. During his exile, Argyropoulos had been pivotal in helping the humanists of Florence translate and reassess the works of Aristotle, whose broad range of writings on natural philosophy had been studied only very selectively in Europe during the Middle Ages, by Christian scholars interested only in those parts of his work that would help buttress their theology and metaphysics. Toscanelli, for his part, would have been a hugely appealing figure to Leonardo. A widely respected authority on subjects as varied as astronomy, geography, linear perspective, mathematics, and optics, and a friend of artists, humanists, and scholastics alike, he exerted a long and powerful influence on Florentine intellectual and cultural life. His circle included not only Alberti, Verrocchio, and Marsilio Ficino, the dean of the Florentine Neoplatonists, but also Brunelleschi—inside whose dome, in about 1468, he constructed a giant gnomon that for centuries afterward was used to make precise observations of the sun’s wanderings. Today, however, he’s best known for something else: the letter he wrote to a Portuguese friend in 1474,proposing that the best way to reach the Far East from Europe was not to sail east, under Africa, but west, across the uncharted Atlantic. Several years later, that letter would catch the attention of Christopher Columbus, who in turn would write to Toscanelli to ask for more information—and the brief correspondence the two men entered into supposedly helped convince Columbus to set sail in 1492. All of which leads to a remarkable thought: in the year or two before his death, in 1482, Toscanelli may have dispensed advice to both Leonardo da Vinci and Christopher Columbus.
    Needless to say, Leonardo’s investigations into natural philosophy consumed vast amounts of time and energy, and, inevitably, his productivity as an artist suffered. (Given the almost infinitely expanding nature of his interests and investigations, however, the wonder really is not that he