We must doubt the certainty of everything which passes through the senses, but how much more ought we to doubt things contrary to the senses, such as the existence of God and the soul.
Leonardo da VinciWhen the thing taken into union is perfectly adapted to that which receives it, the result is delight and pleasure and satisfaction.
Leonardo da VinciYou will never have a greater or lesser dominion than that over yourself...the height of a man's success is gauged by his self-mastery; the depth of his failure by his self-abandonment. ...And this law is the expression of eternal justice. He who cannot establish dominion over himself will have no dominion over others.
Leonardo da Vinci