ASPECTS OF KINETIC EVOLUTION 283 



selection. This, at least, would not wholly misrepresent the 

 facts of nature, for evolution accomplishes the results which it 

 has been customary to ascribe to selection. 



Unless evolution were going on the selective effects would not 

 appear. The older writers commonly made the confusion even 

 worse by assuming that adaptation and evolution are the same. 

 Adaptation is not evolution, but only a special kind or result of 

 evolution. Selection aids evolution to produce adaptation. 

 Translating again into scholastic language, evolution is the 

 efficient cause of adaptations, while selection is the occasional 

 cause or condition which conduces to adaptations. Adaptive 

 characters are brought into existence in the same way as other 

 characters, by the evolutionary motion of species. Adaptation 

 can be said to be caused by selection only as a pure abstraction, 

 when it refers merely to the deflection which environmental 

 obstacles have induced in the normal motion of the species. 



The confusion of ideas has not been limited to advocates of 

 natural selection, but is shared even by its most active opponents. 

 Thus Mivart, in a book written to show the inadequacy of the 

 selective theory of evolution, admits for selection a power which 

 it does not have : 



" ' Natural Selection,' simply and by itself, is potent to explain 

 the maintenance or the further extension and development of 

 favorable variations, which are at once sufficiently considerable 

 to be useful from the first to the individual possessing them. 

 But Natural Selection utterly fails to account for the conserva- 

 tion and development of the minute and rudimentary beginnings, 

 the slight and infinitesimal commencements of structures, how- 

 ever useful those structures may afterward become." 1 



As long as we fail to perceive that selection is not a cause of 

 evolution the issue remains uncertain. If selection is able to 

 cause even a little evolution it might, with time, cause much. 

 The " slight individual differences" may suffice for the work, 

 as Darwin claimed, and the practicability of a selective evolu- 

 tion appears to turn on such arguments as the amount of time 

 estimated by geologists and physicists from considerations even 

 more obscure than those of biology itself. Selection is not 



1 Mivart, St. George, 1871. On the Genesis of Species, New York ed., p. 35. 



