EARLT EVOLUTIONARY VIEWS. 27 



Aristotle. Unlike Plato, who laid special stress on 

 a priori reasoning as the source of true knowledge, 

 even in the natural and physical sciences, he insisted 

 on observation and experiment. " We must not," 

 he tells us in his " History of Animals," "accept a 

 general principle from logic only, but must prove its 

 application to each fact. For it is in facts that we 

 must seek general principles, and these must always 

 accord with facts. Experience furnishes the partic- 

 ular facts from which deduction is the pathway to 

 general laws." 



When we consider how happy the Stagirite was 

 in his generalizations from the meager facts at his 

 command, how remarkable was his prevision of 

 some of the most important results of modern 

 investigation, how he had not only a true concep- 

 tion of the modern ideas of Evolution, but had 

 likewise a clear perception of the principle of adap- 

 tation, when we remember that he was cognizant 

 of the analogies, and probably also of the homol- 

 ogies between the different parts of an organism, 

 that he was aware of the phenomena of atavism and 

 reversion and heredity, and that he foreshadowed 

 the theory of epigenesis in embryonic development, 

 as taught by Harvey long ages afterwards, when we 

 call to mind all these things, we are forced, I re- 

 peat, to conclude that the immortal Greek not only 

 fully understood the value of induction as an instru- 

 ment of research, but also that he was quite as suc- 

 cessful in its use, considering his limited appliances 

 for work, as was any one of his successors who lived 

 and labored in more favored times. 



