FACT OF EVOLUTION TO THE PHILOSOPHY OF EVOLUTIONISM 359 



Philosophies of evolutionism, and they are as old as Hera- 

 clitus, are distinct from scientific evolutionary theory, and they 

 take various shapes and meanings depending upon their pri- 

 mary assumptions. After Darwin, however, the various ide- 

 ologies began to be framed in the context of evolutionary 

 science, and the names Spenser, Marx, James, Bergson, Le Roy, 

 Dilthey and Jaspers come to mind as representing some ex- 

 pression of a philosophy of evolutionism."^ It is, in a limited 

 sense, true to say that evolutionism, historicism and existen- 

 tialism are fundamentally identical expressions on different 

 levels of being: cosmic evolution, evolutionism; mankind's 

 evolution, historicism; personal evolution, existentialism. The 

 emergence of ideological expressions of evolutionism from the 

 scientific study of origins and prehistory, the outstanding fea- 

 ture of American evolutionary thought in the last decade 

 (crowned by the Darwin Centennial in 1959) , results from two 

 dangerous tendencies in scientific thought. 



Fundamental Errors 



The first of these is the unrestricted and uncritical use of the 

 scientific device of extrapolation. x4.t the Convention, Olson 

 warned against its dangers.'^ Simpson declared its limitations.^" 

 Piggott is severely critical of every form of extrapolation, 

 whether it be interpolation, interpretation, analogy or any 

 other form of filling in the gaps of our knowledge with " postu- 

 lates which fulfill an emotional need." ^^ Case, Le Gros Clark, 

 Gaffron and many others have tried to make explicit the limits 

 of this necessary device of scientific prehistory.*' But there is 

 no doubt that what often appears in text-books and the more 

 popular expressions of current thought on origins is far from 



'* The interrelationship of these ideologies is clearly traced in I. M. Bochenski, 

 Contemporary European Philosophy (Berkley, 1957) . 



'" EAD, I, 532. 



^°EAD,I, 121. 



^^EAD, II, 92. 



*^ E. C. Case, op. cit.; Le Gros Clark, The Fossil Evidence For Human Evolution, 

 loc. cit.; Gaffron, EAD, I, pp. 44-50. 



