CHAPTER VI 



NATURAL-PHILOSOPHICAL SYSTEMS AFTER ARISTOTLE 



Aristotle' s folloivers 



WHEN Aristotle fled from Athens he left his school in the hands of 

 Theophrastus, who had been his faithful friend and follower ever 

 since his student days with Plato. Though ten years younger than 

 his master, Theophrastus was an old man when he assumed the leadership of 

 the Lyceum, but he lived much longer and for more than thirty years presided 

 with honour over the education of the pupils. Already under Aristotle he had 

 paid special attention to the study of botany and he continued to work in 

 this science in the spirit of his master. His two treatises on plants are to 

 botany what Aristotle's works were to zoology. Furthermore, there is extant 

 a "history of physics" by him, which has always been the main source of 

 our knowledge of the ideas of the ancient natural philosophers. He also 

 wrote a zoological work, which has been lost, but on the whole it seems to 

 have contained nothing essentially new that is not found in Aristotle. 



On the other hand, Theophrastus' successor, Strato, developed Aris- 

 totle's theory along entirely fresh lines. Unfortunately the present age is 

 acquainted with his point of view only through the references of other 

 authors, but from these it is clear that he was a truly independent thinker. 

 Born at Lampsacus in Asia Minor, he became a disciple of Theophrastus at 

 an early age, and after the latter's death held his professorship for eighteen 

 years. His numerous writings, now lost, dealt particularly with problems of 

 natural science and procured him the title of "the physicist." In contrast to 

 Aristotle he denied the existence of a dominant intelligence outside the uni- 

 verse; he imagined that the forces that govern the course of events dwell in 

 things themselves and operate by natural necessity. Further, the soul of 

 man he believed to be a force inhabiting the body, expressing itself as motion, 

 and having the brain for its organ. On the other hand, he seems to have at- 

 tacked Democritus' theory of the atoms and infinite space and considered 

 the whole world to be finite. 



Strato's successors appear to have been men of little importance, and 

 although Aristotle's school survived down to the sixth century after Christ, 

 it nevertheless ceased to act as a guiding light in science; its teachers and 

 pupils became for the most part involved in specialized investigations into 

 grammar, literature, and ethics, and the keen interest in the natural sciences 



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