One thing that struck me at an exhibit of Leonardo's notebooks is how totally wrong he was about so many things. It wasn't mentioned in the exhibit but for every one thing he was correct about, it seemed like there were many many, dozens perhaps, that he was completely incorrect about. Some of the ideas seem preposterous now, although it's difficult to view them appropriately as they would have been at the time.

This could be seen positively or negatively. One way of spinning it is that he was persistent in exploring ideas. Another way, though, is that something -- mythmaking, hype, his art, whatever it is -- has allowed history to ignore the fact that he seemed to have been wrong more often than he was right, along the lines of a broken clock being right twice a day.

In either case, I think there's something to be said for some kind of cultural and social context playing a strong role in how all of this is interpreted. A different person in the wrong place or wrong time might have been interpreted as a crackpot.