CHAPTER IV 
IS ORGANIC EVOLUTION AN ESTABLISHED PRINCIPLE? 
H. H. NEwMAan 
1. Is there definite proof of organic evolution ? 
2. If so, what is the nature of the proof? 
3. What are the evidences of evolution, and in what ways do these 
bear witness that evolution has occurred and is still occurring ? 
Before presenting in any detail the several bodies of data that 
constitute the ‘‘evidences of evolution,” let us anticipate a little by 
attempting to answer the three questions just propounded. 
1. Reluctant as he may be to admit it, honesty compels the 
evolutionist to admit that there is no absolute proof of organic 
evolution. But, for that matter, there is no absolute proof of any- 
thing that depends on records of past events. We have no absolute 
proof that Caesar or Napoleon once lived, or fought, or conquered. 
All we have are the accounts left by the historians which we accept 
without question because they are the products of human thought and 
imagination. There is no absolute proof for either of the more or less 
directly opposed theories of the origin of the material universe: the 
“nebular hypothesis” of Laplace, and the “planetesimal hypothesis”’ 
of Chamberlin and Moulton. Both of these theories rest upon 
exactly the same types of evidences as does the theory of organic evolu- 
tion, viz., the amassing of facts which appear to be explicable on the 
assumption that the one or the other theory is true. If all of the facts 
are in accord with it, and none are found that are incapable of being 
reconciled with it, a working hypothesis is said to have been advanced 
to the rank of a proved theory. As yet it is impossible to say that 
either of these theories as to the origin of the universe has been proved. 
Yet there is much less popular opposition to the acceptance of these 
theories as facts than there is to the general theory of organic evolu- 
tion. Similarly, there are certain widely accepted theories of the 
origin of the present conditions of the earth’s crust, and its liquid and 
gaseous envelopes. The accepted theory, as given us by Hutton and 
especially by Lyell, is essentially an evolutionary theory and depends 
for its proof on almost exactly the same types of evidence as does that 
57 
