Leonardo Da Vinci.
After all the cant which has been written about Leonardo I'd like to put forward some real, justifiable, thoughts on the subject of the man's philosophy.
Particularly, where his philosophical thoughts fall in relation to the history of philosophy.
His philosophical musings are rather odd in that, well, for a couple of reasons, the first being that he appears to have been totally convinced that a thing does not exist apart from all of the different ways in which it can appear to the eye.
That's sort of strange, but what's more curiouser, you could say, is that this Rennaisance man's philosophy is actually a mixture of medieval and rennaisance philosophy, not the pure sort of rennaisance philosophy found, for example, in Pico di Mirandola's works.
Specifically, Leonardo's thought seems to be a mixture of Neo-Platonism and the medieval platonism which proceeded from Plotinus, which became the source of philosophy for the west after the fall of the Roman empire, and which stayed in that position until Aquinas reintroduced Aristotle.
Even stranger is that the Medieval Platonists appear to have mattered more to Leonardo's thought than the Neo-Platonists, who were his contemporaries, did.
The results of this, though, are positive rather than negative; for the Neo-Platonists of the Rennaisance, in working out a humanistic philosophy based on those principles, fell into what G.K. Chesterton, in his biography of Aquinas, contended that the pre-Thomist Christian theorists went wrong on: constructing a very elaborate theoretical framework which, despite it's care, has little to do with the thinking and feeling reality of everyday life.
The Neo-Platonists, in talking about man in cosmic terms, tend to sever their connection with man as a mortal being incarnated in this world.
The Medieval philosophers who built on Plotinus, meanwhile, never lost that essential connection to the tangible, and that connection is what Leonardo grafts his Neo-Platonist ideas onto, making his presentation of the world as a series of images in some way coming from a final nature a more realistic presentation about how the world actual appears and feels to people.
One can both intellectually and practically understand where Leonardo is coming from, which, by the way, is what he declares his whole point to be in his remarks about the neccesity of learning from experience as opposed to just repeating what books have said about a subject.