CHAPTER VIII 



A Factor in Evolution : Organic Selection ^ 



In several recent publications ^ some considerations are 

 developed, from different points of view, which tend to 

 bring out a certain influence at work in organic evolution 

 which we may venture to call a 'factor.' The object of 

 the present paper is to gather into one sketch an outline 

 of the view of the process of evolution which these 

 different publications have hinged upon. 



The problems involved in a theory of organic evolution 

 may be gathered up under three great heads : Ontogeny 

 or the individual's development, Phylogeny or the evolu- 

 tion of species, and Heredity. The general consideration, 

 the ' factor ' which it is proposed to bring out, is operative 

 in the first instance, in the field of Ontogeny ; I shall con- 

 sequently speak first of the problem of Ontogeny ; then of 

 that of Phylogeny, in so far as the topic dealt with makes 

 it necessary ; then of that of Heredity, under the same 

 limitation ; and finally, give some definitions and con- 

 clusions. 



1 From the American Naturalist, June and July, 1896, article entitled ' A 

 New Factor in Evolution.' Slightly revised as to terminology mainly, in 

 accordance with the recommendations of the biological authorities of the 

 writer's Dictionary of Philosophy {sub verbis). 



2 Preceding papers in this work. This essay was written to gather together 

 the various points of view of the earlier papers, hence the frequent quotations 

 from them. 



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