Mechanism and Purpose 411 



We have seen that there are many theories of evolution, 

 and that the earher ones for the most part introduced an 

 element of purpose — whether of an outside agency, or of 

 an internal one. In either case such an assumption leaves 

 us entirely in the dark when we seek to understand how 

 things work, or how events come to pass. We can see that 

 it is one thing to accept the explanation of rain, for example, 

 that it is designed to meet a certain need, or that it is provided 

 in order to carry out a certain purpose; but that it furnishes 

 a different understanding to explain the weather in terms of 

 changing temperature and humidity. The latter type of 

 explanation still leaves us in ignorance as to why water 

 vapor condenses to liquid as and when it does, or as to why 

 liquid changes to vapor at a certain temperature, or why the 

 atmosphere will hold only so much vapor and not more. 

 In short, the mechanistic view answers for us only questions 

 regarding the how, but cannot answer why. On the other 

 hand, the answers which men attempt to give to the ques- 

 tion " why? '^ do not lend themselves to scientific scrutiny 

 and further elaboration. They may satisfy because they are 

 reasonable, but they cannot be verified or tested. 



The scientist accepts the facts as given and seeks to find 

 the uniformities in the behavior of materials and forces; and 

 these uniformities we designate " laws." 



Law and Miracle 



We have been taught to think not only in terms of cause 

 and effect, but also in terms of continuity. We have been 

 impressed with the uniformity of " laws " in the universe 

 and are therefore wary of " explanations " that seem to vio- 

 late principles of consistency or unity. Evolution would 

 offer no difficulty if we were prepared to believe in mira- 

 cles, if we could believe, for example, that rabbits could 

 be born along with kittens from a mother cat; but such 

 miracles are unbelievable to one who knows the elementary 

 facts — and uniformities — of mammalian reproduction* 



