THE 



POPULAR SCIENCE 

 MONTHLY. 



OCTOBER, 1887. 



WHAT IS EVOLUTION?* 



By Professor JOSEPH LE CONTE. 



EVERY one is familiar with the main facts connected with the 

 development of an egg. We all know that it begins as a micro- 

 scopic germ-cell, then grows into an egg, then organizes into a chick, 

 and finally grows into a cock ; and that the whole process follows some 

 general, well-recognized law. Now, this process is evolution. It is 

 more it is the type of all evolution. It is that from which we get 

 our idea of evolution, and without which there would be no such word. 

 Whenever and wherever we find a process of change more or less re- 

 sembling this, and following laws similar to those determining the 

 development of an egg, we call it evolution. 



Evolution as a, process is not confined to one thing, the egg, nor as 

 a doctrine is it confined to one department of science biology. The 

 process pervades the whole universe, and the doctrine concerns alike 

 every department of science yea, every department of human thought. 

 It is literally one half of all science. Therefore, its truth or falseness, 

 its acceptance or rejection, is no trifling matter, affecting only one small 

 corner of the thought-realm. On the contrary, it affects profoundly 

 the foundations of philosophy, and therefore the whole domain of 

 thought. It determines the whole attitude of the mind toward Nature 

 and God. 



I have said evolution constitutes one half of all science. This may 

 seem to some a startling proposition. I stop to make it good. 



Every system of correlated parts may be studied from two points 

 of view, which give rise to two departments of science, one of which 

 and the greater and more complex is evolution. The one concerns 

 changes within the system by action and reaction between the parts, 



* From advance sheets of Professor Le Conte's work on " Evolution and its Relation 

 to Religious Thought," in preparation by D. Appleton & Co. 

 vol. xxxi. 46 



