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 VinciIt vexes me greatly that having to earn my living has forced me to interrupt the work and to attend to small matters.
Leonardo da VinciThe painter who draws merely by practice and by eye, without any reason, is like a mirror which copies every thing placed in front of it without being conscious of their existence.
Leonardo da Vinci