33 Problems of Organic Adaptation 



and biologists to find an explanation for adaptation. One 

 need only enumerate the "supernatural design" of theolo- 

 gians, the "perfecting principle" of Aristotle and Nageli, 

 the "indwelling soul" of Plato and Bruno, the "active teleo- 

 logical principle" of Kant, the "unconscious purpose" of 

 Hartmann, the "vital activity" or "vitalism" of Bunge, 

 Wolff, and Virchow, the "will" of Schopenhauer, the "elan 

 vital" of Bergson, the "entelechy" of Driesch, the "archaes- 

 thetism" of Cope, the "desire" or "need" of Erasmus Dar- 

 win and Lamarck, and finally Charles Darwin's "natural 

 selection," to indicate over what a wide field these attempted 

 explanations have ranged. All of these proposed explana- 

 tions may be classified as natural or supernatural, or more 

 accurately as mechanistic or vitalistic. The former presup- 

 pose only natural forces and processes in the regular se- 

 quence of cause and effect; the latter assume that some form 

 of will or purpose is present as an uncaused cause which lies 

 outside the field of scientific inquiry. 



If for the present we pass over those views which attempt 

 no casual explanation, but merely restate the mystery in 

 terms of supernatural design, perfecting principles, or entel- 

 echies, and those which find the causes of adaptations in 

 unknown laws of variation or of physiological response, 

 there remain two attempted explanations of organic fitness 

 which may be known by the general terms of Lamarckism 

 and Darwinism, though at present neither of these systems 

 represents accurately the views of the man whose name it 

 bears. 



/. Lamarckism 



Lamarckism attempts to explain racial adaptations as the 

 result of the inheritance of individual or acquired adapta- 

 tions; it is assumed that the beneficial responses which are 

 called forth in individuals by external stimuli are handed 



