Being engulfed in practice without delicate knowledge related to it, is in many ways like entering a ship without knowing where it is headed.
Leonardo da VinciI say that the power of vision extends through the visual rays to the surface of non-transparent bodies, while the power possessed by these bodies extends to the power of vision.
Leonardo da VinciThose who, in debate, appeal to their qualifications, argue from memory, not from understanding.
Leonardo da Vinci