To me it seems that those sciences are vain and full of error which are not born of experience, mother of all certainty, first-hand experience which in its origins, or means, or end has passed through one of the five senses. And if we doubt the certainty of everything which passes through the senses, how much more ought we to doubt things contrary to these senses – ribelli ad essi sensi – such as the existence of God or of the soul or similar things over which there is always dispute and contention. And in fact it happens that whenever reason is wanting men to cry out against one another, which does not happen with certainties. For this reason we shall say that where the cry of controversy is heard, there is no true science, because the truth has one single end and when this is published, argument is destroyed for ever.

Hippolyte Taine wrote in 1866: "There may not be in the world an example of another genius so universal so incapable of fulfilment so full of yearning for the infinite so naturally refined so far ahead of his own century and the following centuries. Leonardo is revered for his technological ingenuity. There are compositions for paintings studies of details and drapery studies of faces and emotions of animals babies dissections plant studies rock formations whirlpools war machines helicopters and architecture.

He conceptualised a helicopter a tank concentrated solar power a calculator and the double hull and he outlined a rudimentary theory of plate tectonics. Leonardo is revered for his technological ingenuity. Among his works the Mona Lisa is the most famous and most parodied portrait and The Last Supper the most reproduced religious painting of all time with their fame approached only by Michelangelo's The Creation of Adam.