THE RENAISSANCE 107 



many of the men of the Renaissance. 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 

 conclusive. 



Leonardo approached science from the practical 

 side, and it is owing to this lucky fact that much of 

 his modern spirit is due. To meet the practical 

 necessities of his crafts, he began experimenting, 

 though in his later years the thirst for knowledge 

 overcame the love of art. It was needful for an 

 artist to understand the laws of optics and the structure 

 of the eye, the details of human anatomy, and the 

 flight of birds. As an engineer, both civil and military, 

 Leonardo was faced by problems which could only 

 satisfactorily be solved by an insight into the prin- 

 ciples of mechanics, both static and dynamic. Now 

 Aristotle's opinion was of small help in correcting a 

 picture out of drawing, in managing water for irriga- 

 tion, or in taking a fortified city. For these problems, 

 the behaviour of things as they were was of more 

 importance than the opinion of the encyclopaedic 

 Greek as to what they ought to be. 



But Leonardo was also a philosopher, and as a 

 philosopher he probably most affected the thought and 

 mental attitude of his contemporaries. The most 

 striking change we observe when comparing his mode 

 of thought with that of the preceding age, is his almost 

 complete emancipation from theological preconcep- 

 tions. Even Roger Bacon, with all his love of enquiry, 

 regarded theology as the true summit and end of all 

 knowledge, and doubted not that all learning would 

 prove consistent with the chief dogmas of his day. 



