CHAPTER XXXV 

 THEORIES OF EVOLUTION 



Pre-Darwinian Science. — Although Darwinism and 

 evolution are popularly believed to be synonymous terms, 

 the general notion is actually older than the Christian 

 Era. In the writings of the Greek philosophers the idea 

 is occasionally expressed, usually in very vague language 

 unsupported by facts, to account for the origin and 

 development of the universe, including the organic world. 

 A notable exception appears in the case of Aristotle (384- 

 322 B.C.). In the realm of biology he classified over five 

 hundred animals, understood adaptation, recognized the 

 meaning of physiological division of labor, studied em- 

 bryology, and advanced the science of living things to the 

 position it held for sixteen hundred years. Aristotle also 

 believed that inorganic matter evolved into a soft mass, 

 living but unorganized, from which higher species gradu- 

 ally developed as a result of an internal impelling force. 

 In certain important respects his theory resembles that 

 held by the modern biologist. 



After the time of Aristotle, both science and the desire 

 to find a natural explanation for the origin of things 

 underwent a decline lasting until the 12th century. 

 Toward the close of this period the writings of the Greek 

 philosophers were translated by the Arabs, who, under 

 their influence, founded the first universities that had 

 existed for centuries. As a result of this intellectual 

 awakening, a large number of students arose who pro- 

 foundly influenced scientific thought, and directly or in- 

 directly laid the foundations of modem science. 



The Influence of Darwin's Work. — During the 



420 



