Now do you not see that the eye embraces the beauty of the whole world? It counsels and corrects all the arts of mankind... it is the prince of mathematics, and the sciences founded on it are absolutely certain. It has measured the distances and sizes of the stars it has discovered the elements and their location... it has given birth to architecture and to perspective and to the divine art of painting.
Leonardo da VinciHe who loves practice without theory is like the sailor who boards ship without a rudder and compass and never knows where he may cast.
Leonardo da VinciLearning acquired in youth arrests the evil of old age; and if you understand that old age has wisdom for its food, you will so conduct yourself in youth that your old age will not lack for nourishment.
Leonardo da VinciStudy me, reader, if you delight in me, because on very few occasions shall I return to the world, and because the patience for this profession is found in very few, and only in those who wish to compose things anew. Come, oh men, to see the miracles that such studies will disclose to nature.
Leonardo da Vinci