THE EVOLUTION IDEA 133 



point to which observation should be directed was 

 not the past but tlie present mutabihty of spe- 

 cies, and further, that this mutabihty was simply 

 tlie variation of individuals on an extended scale. 

 Thus Variation was brought into prominence as 

 the point to which observation should be directed. 

 This is one of the contributions of the natural 

 philosophers to the history of the evolution the- 

 OTV. It seems to have sprung up afresh out of 

 the advances in biology of the previous century, 

 for it was something which is not found among 

 the Greeks. It was Bacon who pointed out the 

 evidence for Variation in animals and plants, 

 and the bearing of this upon the production of 

 new species and upon the gradations of life. 

 Leibnitz took a second step in indicating that the 

 evolution of life was a necessary part of a sys- 

 tem of cosmic philosophy, and although wholly 

 at sea in his theory of Evolution, he added to the 

 evidence for it by giving examples of gradations 

 of character between living and extinct forms, as 

 proofs of the universal gradation or connection 

 between species. Thus among these philosophers 

 we are astonished to find pointed out the grada- 

 tions of animal types, the facts of variation, and 

 the bearing of these facts upon the production of 

 new species, also the analogy between artificial 

 selection practised by man in producing new 

 forms and the production of new forms in Na- 

 ture. 



