228 EVOLUTION OF THE SCIENTIFIC INVESTIGATOR. 



('\t'iil of modcni times. Px'fore this event the intellert was hoiiml down 

 by a sehohisticisni which re<i'ar(le(l knowledge as a rounded whole, 

 the ]jai'ts of which were w ritten in books and carried in the minds of 

 learned men. The student was taught from the l)eginning of his 

 work to look u])on authority as the foun(hition of his beliefs. The 

 ohler the authority the greater the Aveight it carried. So eifective 

 was this teaching that it seems never to have occurred to individual 

 men that they had all the opportunities ever enjoyed l)y Aristotle of 

 discovering truth, with the added advantage of all his knowledge to 

 begin Avith. Advanced as was the development of formal logic, that 

 practical logic was wanting which could see that the last of a series 

 of authorities, every one of which rested on those which i)receded it, 

 could never form a surer foundation for any doctrine than that sup- 

 plied by its original propounder. 



The result of this view of knowdedge was, that although during 

 the fifteen centuries following the death of the geometer of Syracuse 

 great universities were founded at which generations of professors 

 expounded all the learning of their time, neither professor nor student 

 ever suspected what latent jjossibilities of good were concealed in the 

 n)ost familiar operations of nature. Everyone felt the wind blow, 

 saw watei' boil, and heard the thunder crash, but never thought of 

 investigating the forces here at play. Up to the middle of the 

 fifteenth century the most acute observer could scarcely have seen 

 the dawn of a new era. 



In view of this state of things, it nmst be regarded as one of the 

 most remarkable facts in evolutionary history that four or five men, 

 Avhose mental constitution was either typical of the ne^v order of 

 things or wdio w^^re poAverful agents in bringing it about, were all 

 born during the fifteenth century, four of them at least at so nearly 

 the same time as to l)e contem]:»()raries. 



Leonardo da Vinci, Avhose artistic genius has charmed succeeding 

 generations, was also the first practical engineei- of his time, and tlu' 

 first man after Archimedes to make a substantial advance in develo})- 

 ing the laws of inolion. That the woidd was not prei)ared to make 

 use of his scientific discoveries does not detract from the significance 

 which must attach to the jn'riod of his birth. 



Shortly after him was born the great navigator whose bold si)irit 

 Avas to make known a new world, thus gi\ing to connnercial enter- 

 prise that impetus Avhich was so poweid'ul an agent in bi-inging about 

 a revolution in the thoughts of men. 



The birth of Columbus was soon followed by tiiat of Copernicus, 

 the first after Aristai'chus to demonstrate the true system of the 

 world. In him more than in any of his contemporaries do Ave see the 

 struggle betAveen the old forms of thought and the neAv. It seems 

 almost pathetic, and is certainly most suggestive of the general A'iew 



