ADAPTATION 179 



been invoked at every turn and step in biological inquiries. 

 It has been assumed that any result, bodily or mental, could 

 be attributed to Natural Selection. 



The following example, will illustrate the difference between 

 the ways a teleologistand an Evolutionist would regard the same 

 phenomenon, Rev. W. Kirby, in the second volume of his 

 Bridgewater Treatise, dealing with ihe history, habits and 

 instincts of animals (1835), says of the hermit crabs, " whose 

 abdomen being naked, and unprotected by any hard crust, their 

 Creator has given them an instinct, which teaches them to com- 

 pensate this seeming defect, by getting possession of some 

 univalve shell, suited to their size, which becomes their habi- 

 tation, and which they carry about with them as if they were its 

 proper inhabitants. These crabs are particularly formed for 

 the habit that distinguishes them." After describing several 

 points of structure in adaptation to their abode, Mr. Kirby 

 concludes, " This whole structure proves that they are formed 

 with this particular view of inhabiting shells of a very different 

 tribe of animals". 



An Evolutionist inverts this interpretation. The "crabs," 

 having chosen to live in shells for some reason or other, 

 possibly for concealment to catch their passing prey, just as 

 some fishes bury themselves in the mud for a similar purpose, 

 degeneration from disuse has set in, and the hinder part 

 has modified itself as to become adapted to the shell ; so 

 that now the hermit crabs cannot exist without such a pro- 

 tection. 



Design is always in anticipation of a use ; adaptation is 

 always the result of it whether it bring about degeneration or 

 enhancement ; usually both occur simultaneously. 



Hence under Evolution, as I have already stated, structure 

 is never made at first in anticipation of a future requirement ; 

 but when once established by use or adaptation, then it is 

 developed before its use can be employed, as in the forma- 

 tion of the eye of a mammal while as a foetus. 



Natural Selection does not hesitate to use teleological 



