14 Darwin, and after Darwin. 



know the natural causes of many diseases ; but yet 

 no one nowadays thinks of reverting to any hypo- 

 thesis of a supernatural cause, in order to explain the 

 occurrence of any disease the natural causation of 

 which is obscure. The science of medicine being in 

 so many cases able to explain the occurrence of 

 disease by its hypothesis of natural causes, medical 

 men now feel that they are entitled to assume, on the 

 basis of a wide analogy, and therefore on the basis of 

 a strong antecedent presumption, that all diseases are 

 due to natural causes, whether or not in particular 

 cases such causes happen to have been discovered. 

 And from this position it follows that medical men 

 are not logically bound to entertain any supernatural 

 theory of an obscure disease, merely because as yet 

 they have failed to find a natural theory. And so it 

 is with biologists and their theory of descent. Even 

 if it be fully proved to them that the causes which 

 they have hitherto discovered, or suggested, are in- 

 adequate to account for all the facts of organic nature, 

 this would in no wise logically compel them to vacate 

 their theory of evolution, in favour of the theory of 

 creation. All that it would so compel them to do 

 would be to search with yet greater diligence for the 

 natural causes still undiscovered, but in the existence 

 of which they are, by their independent evidence in 

 favour of the theory, bound to believe. 



In short, the issue is not between the theory of a 

 supernatural cause and the theory of any one parti- 

 cular natural cause, or set of causes such as natural 

 selection, use, disuse, and so forth. The issue thus 

 far or where only \hefact of evolution is concerned 

 is between the theory of a supernatural cause as 



