Every action needs to be prompted by a motive. To know and to will are two operations of the human mind. Discerning, judging, deliberating are acts of the human mind.
Leonardo da VinciJust as eating against one's will is injurious to health, so studying without a liking for it spoils the memory, and it retains nothing it takes in.
Leonardo da VinciIf you cause your ship to stop and place the head of a long tube in the water and place the outer extremity to your ear, you will hear ships at a great distance from you.
Leonardo da VinciAvoid the precepts of those thinkers whose reasoning is not confirmed by experience.
Leonardo da Vinci