In classic Steve fashion, he would agree to something, but it would never happen,” said Lack. “He would set you up and then pull it off the table. He… - Walter Isaacson

Kenneth Clark referred to Leonardo’s “inhumanly sharp eye.” It’s a nice phrase, but misleading. Leonardo was human. The acuteness of his observational skill was not some superpower he possessed. Instead, it was a product of his own effort. That’s important, because it means that we can, if we wish, not just marvel at him but try to learn from him by pushing ourselves to look at things more curiously and intensely. 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.

The family adopted a motto: “Live dangerously — carefully.

Blind respect for authority is the greatest enemy of truth.