406 FOUNDATIONS OF BIOLOGY 



Mendelian formula takes place. Such is the deeply hidden 

 modicum of truth in the old preformation theories! 



7. Organic Evolution 



A question which has interested and perplexed thinking 

 men of all times is how things came to be as they are to-day. 

 The historian of human affairs attempts to trace the sequence 

 and relationship of events from the remote past to the pres- 

 ent. Similarly, the geologist endeavors to formulate the 

 history of the Earth; arid the biologist, the history of plants 

 and animals on the Earth. All recognize that the present is 

 the child of the past and the parent of the future, and that 

 past, present, and future, though causally related, are never 

 the same. It was the Greek natural philosophers who pro- 

 jected this idea of history into science and attempted to 

 substitute a naturalistic explanation of the Earth and its 

 inhabitants for the established theogonies, and thus started 

 the uniformitarian trend of thought which culminated in the 

 establishment of organic evolution during the past century. 



Aristotle held substantially the modern idea of the evolu- 

 tion of life from a primordial mass of living matter to the 

 higher forms, 'and placed Man at the head of animal creation. 

 "To him belongs the God-like nature. He is preeminent by 

 thought and volition. But although all are dwarf-like and 

 incomplete in comparison with Man, he is only the highest 

 point of one continuous ascent." And evolution is still going 

 on the highest has not yet been attained. In looking for 

 the effective cause of evolution Aristotle rejected the hy- 

 pothesis of EMPEDOCLES (495-435 B.C.), which embodied in 

 crude form the idea of the survival of the fittest, and substi- 

 tuted secondary natural laws to account for the apparent 

 design in nature. This was a sound induction by Aristotle 

 from his necessarily limited knowledge of nature, but had he 



