56 DOCTRINE OF EVOLUTION 



a real and a natural process. We see it everywhere 

 about us and we ourselves have come to be what we 

 are by a natural history of change. Can we consistently 

 deny that it is possible for a species to alter in the long 

 course of time when a few brief weeks are sufficient for 

 the new-laid egg of the fowl to develop into a fledgling ? 

 Many indeed strain at the gnat of the longer process 

 in the past when without hesitation they recognize the 

 real and obvious fact of individual development in a 

 brief period. 



I have said that development is a ''natural" process. 

 We employ this word for the familiar and everyday 

 occurrence or thing ; it does not imply that everything 

 is known about the object or phenomenon, because 

 science knows that complete and final knowledge is 

 impossible. We say that it is natural for rain to fall 

 to the earth, and we speak of the law of gravitation 

 according to which this takes place as a natural prin- 

 ciple, but it may not have occurred to many to inquire 

 what makes rain fall and why do masses of matter 

 everywhere behave toward one another in the consistent 

 manner described by the law in question. Sunshine 

 is natural, but we do not know why light travels as it 

 does from the sun to the earth, and this is another 

 question which, like the inquiry into the ultimate cause 

 of the familiar and natural phenomenon of gravitation, 

 has not yet been answered. But it is still regarded as 

 natural for the rain to fall and for the sun to shine. 

 In the same way does science view development, de- 

 noting it natural because it is an ordinary everyday 

 matter. And we are under no more obligation to postu- 

 late supernatural control for the changing forms in the 



