BIOLOGY AND PROGRESS 201 



any theory, collected facts on a wholesale scale, 

 more especially with respect to domesticated pro- 

 duction, by printed inquiries, by conversation with 

 skillful breeders and gardeners, by extensive 

 reading. When I see the list of books of all kinds 

 which I read and abstracted, including whole series 

 of Journals and Transactions, I am surprised at 

 my own industry. I soon perceived that selection 

 was the keynote of man's success in making useful 

 races of animals and plants. But how selection 

 could be applied to organisms living in a state 

 of nature remained for some time a mystery," 



If we separate the scientific method into its 

 parts, a clearer notion of how it operates and how 

 we may operate it, is obtained. These parts are 

 cause, effect, classification. 



1. The scientific method Implies that the hap- 

 penings of to-day are the outgrowth and continua- 

 tion of some previous happenings which it is cus- 

 tomary to speak of as causes. A metaphysical 

 first cause has no place in the scientific method 

 simply because it is something that is unknown. 

 When a happening Is repeatedly found to be asso- 

 ciated with an equally constant result. It Is spoken 

 of as the cause of the result. In the refinements 

 of analysis It Is proper to ask why It is a cause, 

 whether It Is the only cause, or what causes are 

 associated in producing a given result. 



2. When a given fact Is observed to be a cause 



