The Mechanism of Adaptation 333 



It is a mistake to suppose that Lamarckism explains the 

 real origin of adaptations; it maintains that individually 

 acquired adaptations are inherited and thus become racial, 

 but it attempts no other explanation of the origin of indi- 

 vidual adaptations than is to be found in "desire," "need," 

 or "will." The beneficial character of the response of an 

 organism to changes in its environment and to use, disuse, 

 and needs remains as much of a mystery as ever. Lamarck- 

 ians who have attempted to explain acquired adaptations 

 have generally appealed to some mysterious principle, such 

 as unconscious purpose, entelechy, elan vital, or vitalism as 

 contrasted with mechanism; thus the search for the causes 

 of acquired adaptations is removed from the field of scien- 

 tific inquiry. Lamarckism is thus fundamentally non-mech- 

 anistic, and it is not surprising that vitalists and obscuran- 

 tists generally should favor the Lamarckian philosophy. 



In order to explain racial adaptations, Lamarckism begins 

 with the unproved and discredited assumption that individ- 

 ually acquired adaptations are inherited, and in attempting 

 to explain the origin of individual adaptations it ends in a 

 fog of obscurantism or in a bog of mysticism. 



2. Darwinism 



Darwinism, on the other hand, rejects the possibility 

 of the inheritance of such individual or acquired adapta- 

 tions and maintains that there is no genetic connection be- 

 tween racial and individual fitness. It holds that all racial 

 adaptations are due to (i) multifarious variations (muta- 

 tions) among offspring and (2) the elimination by natural 

 selection of those that are poorly adapted. It will be seen 

 that all adaptations that are for the good of the species 

 rather than of the individual admit of no other natural ex- 

 planation, for such adaptations could not have arisen from 



