Leonardo was following a practice that had become popular in Renaissance Italy of keeping a commonplace and sketch book, known as a zibaldone (Location 1755)
Francesco di Giorgio from Siena.8 Thirteen years older than Leonardo, he was another exemplar of an artisan who combined art, engineering, and architecture. He had begun as a painter, moved as a young man to Urbino to work as an architect, returned to Siena to run the underground aqueduct system, and was a sculptor in his spare time. He was also interested in military weaponry and fortifications. In other words, he was the Leonardo of Siena. (Location 2325)
Ideas are often generated in physical gathering places where people with diverse interests encounter one another serendipitously. That is why Steve Jobs liked his buildings to have a central atrium and why the young Benjamin Franklin founded a club where the most interesting people of Philadelphia would gather every Friday. At the court of Ludovico Sforza, Leonardo found friends who could spark new ideas by rubbing together their diverse passions. (Location 2517)
“Before you make a general rule of this case, test it two or three times and observe whether the tests produce the same effects.”7 (Location 2718)
The empirical method used by Bacon emphasized a cycle: observations should lead to a hypothesis, which should then be tested by precise experiments, which would then be used to refine the original hypothesis. Bacon also recorded and reported his experiments in precise detail so that others could independently replicate and verify them. (Location 2751)
In his notebook, he described his method—almost like a trick—for closely observing a scene or object: look carefully and separately at each detail. He compared it to looking at the page of a book, which is meaningless when taken in as a whole and instead needs to be looked at word by word. Deep observation must be done in steps: “If you wish to have a sound knowledge of the forms of objects, begin with the details of them, and do not go on to the second step until you have the first well fixed in memory.”23 (Location 2813)
There is a paradox, which goes back to Zeno in the fifth century BC, involving the apparent contradiction of an object being in motion yet also being at a precise place at a given instant. Leonardo wrestled with the concept of depicting an arrested instant that contains both the past and the future of that moment. He compared an arrested instant of motion to the concept of a single geometrical point. The point has no length or width. Yet if it moves, it creates a line. “The point has no dimensions; the line is the transit of a point.” Using his method of theorizing by analogy, he wrote, “The instant does not have time; and time is made from the movement of the instant.” (Location 2826)
Guided by this analogy, Leonardo in his art sought to freeze-frame an event while also showing it in motion. “In rivers, the water that you touch is the last of what has passed, and the first of that which comes,” he observed. “So with time present.” He came back to this theme repeatedly in his notebooks. “Observe the light,” he instructed. “Blink your eye and look at it again. That which you see was not there at first, and that which was there is no more.”27 (Location 2832)
Known as a paragone, from the Italian word for “comparison,” such a discourse was a way for artists and scholars to attract patrons and elevate their social status during the Italian Renaissance. This was another field in which Leonardo, with his love of both stagecraft and intellectual discussion, could excel as an ornament of the court. (Location 3968)
I think not. Look longer at the picture. It vibrates with Leonardo’s understanding that no moment is discrete, self-contained, frozen, delineated, just as no boundary in nature is sharply delineated. As with the river that Leonardo described, each moment is part of what just passed and what is about to come. (Location 4284)
Each moment incorporates what came right before and what is coming right after. (Location 7583)
