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 VinciMusic cannot be called otherwise than the sister of painting, for she is dependent upon hearing, a sense second to sight, and her harmony is composed of the union of its proportional parts sounded simultaneously, rising and falling in one or more harmonic rhythms.
Leonardo da VinciAll our knowledge hast its origins in our perceptions … In nature there is no effect without a cause … Experience never errs; it is only your judgments that err by promising themselves effects such as are not caused by your experiments … Science is the observation of things possible, whether present or past; prescience is the knowledge of things which may come to pass.
Leonardo da Vinci