78 HISTORY AND SIGNIFICANCE OF SCIENCE 



1519) embodies the spirit of the period. Whether one man 

 can ever again grasp the learning of his day as Leonardo did 

 is doubtful, in view of the present extension of knowledge. 

 But in any era such a man would exert widespread influence. 

 Known mainly as an artist, he was preeminent also as a man 

 of science, an architect, and an engineer. For us, his im- 

 portance lies in his apprehension of the scientific method and 

 in his unique personality. Of him it has been well said, "He 

 was not a scholastic, and neither was he a blind follower of 

 classical authority, as were many of the men of the Renais- 

 sance. To him, observation of nature and experiment were 

 the only true methods of science. Knowledge of the ancient 

 writers, useful as a starting point, could never be conclu- 

 sive." He grasped the fundamental concept that true science 

 begins with observation. "Those sciences are vain and full 

 of errors, he tells us, which are not born from experience, 

 the mother of all certainty, and which do not end with 

 one clear experiment. Science gives certainty, and science 

 gives power. Those who rely on practice without science 

 are like sailors without rudder or compass." Could there 

 be a clearer statement of the nature and value of science 

 even in the twentieth century? 



As indicative of his grasp of fundamentals in scientific 

 method and fact, may be cited his understanding of the 

 nature of fossils and of the changes by which mountains have 

 been upraised, together with the effects of erosion. For 

 example, he says that the Po will eventually lay dry land in 

 the Adriatic as in the past it has deposited a great part of 

 Lombardy. For Leonardo, nature was devoid of magic 

 and subject to immutable necessity. If his fragmentary 

 notes, apparently taken with a view to publication in ency- 

 clopaedic form had become accessible, it is hard to tell what 

 force they might not have exerted in the advancement of 

 science. 6 It is of interest, in view of his renown as an artist, 



6 Among many remarkable passages is the following upon the saltness of the 

 sea. After considering various explanations notably those of Pliny, Leonardo 



