CHAPTER XII 



Determinate Variation and Selection ^ 



A few remarks may be allowed on the subject dis- 

 cussed in the reports of the papers of Professors Osborn 

 and Poulton on ' Organic Selection ' in the issue of 

 Science for October 15, 1897.2 



§ I. Determinate Variation 



I. Professor Osborn's use of the phrase * determinate 

 variation ' seems ambiguous, and the ambiguity is the 

 more serious since it seems to me to prejudice the main 

 contention involved in the advocacy of organic selec- 

 tion. The ambiguity is this : he seems to use determi- 

 nate variation as synonymous with determi^tate evolution^ 

 He says that determinate variation is generally accepted, 

 and attributes that view to Professor Lloyd Morgan and 

 to myself. But it is only determinate evolution that I, for 

 my part, am able to subscribe to ; and I think the same 

 is true of Professor Morgan. 



* Determinate evolution ' means a consistent and uniform 

 direction of progress in evolution, however that progress 

 may be secured, and whatever the causes and processes at 



1 From Science, November 19, 1897 (with additions). 



* Cited in Appendix A. 



8 See his discussion, Science, October 15, pp. 583-584, especially p. 584, 

 column I, and paragraph 2 of column 2. 



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