LEONARDO AND MODERN SCIENCE 75 



as a change, he would go out into the fields and gaze at the stars, 

 or at the earthshine which he could see inside the crescent of the 

 moon; or else, if it were daytime, he would pick up fossils or 

 marvel at the regularities of plant structure, or watch chicks break- 

 ing their shells. . . . Was it not uncanny? Fortunate was he to 

 be born at a time of relative toleration. If he had appeared a cen- 

 tury later, when religious fanaticism had been awakened, be sure 

 this immoderate curiosity would have led him straight to the stake. 



But remarkable as Leonardo's universality is, his earnestness 

 and thoroughness are even more so. There is not a bit of dilet- 

 tantism in him. If a problem has once arrested his attention, he 

 will come back to it year after year. In some cases, we can actually 

 follow his experiments and the hesitations and slow progress of 

 his mind for a period of more than twenty-five years. That is not 

 the least fascinating side of his notes; as he wrote them for his 

 own private use, it is almost as if we heard him think, as if we 

 were admitted to the secret laboratory where his discoveries were 

 slowly maturing. Such an opportunity is unique in the history of 

 science. 



Just try to realize what it means : Here we have a man of con- 

 siderable mother-wit, but unlearned, unsophisticated, who had 

 to take up every question at the very beginning, like a child. 

 Leonardo opened his eyes and looked straight upon the world. 

 There were no books between nature and him; he was untram- 

 melled by learning, prejudice, or convention. He just asked him- 

 self questions, made experiments and used his common sense. The 

 world was one to him, and so was science, and so was art. But 

 he did not lose himself in sterile contemplation, or in verbal gen- 

 eralities. He tried to solve patiently each little problem separately. 

 He saw that the only fruitful way of doing that is first to state the 

 problem as clearly as possible, then to isolate it, to make the neces- 

 sary experiments and to discuss them. Experiment is always at the 

 bottom; mathematics, that is, reason, at the end. In short, the 

 method of inductive philosophy which Francis Bacon was to ex- 



