THE 



AMERICAN NATURALIST 



Vol. LIII. May-June, 1919 No. 626 



ADAPTATION AND THE PEOBLEM OF ORGANIC 

 PURPOSEFULNESS"! 



DR. FRANCIS B. SUMNER 



I. The Reality of the Problem 

 Despite tlie ^'revolutions of thought," which succeed 

 one another with rather bewildering rapidity these days, 

 we may occasionally listen with profit to the voice of a 

 past generation. And I can not believe that we are yet 

 in a position to wholly reject Herbert Spencer's well- 

 known characterization of life as a "continuous adjust- 

 ment of internal relations to external relations." Now 

 it is this process of adjustment to which we give the name 

 adaptation, and the special structures or functions by 

 which the adjustments are carried out are called adapta- 

 tions. 



By earlier biologists and philosophers these facts of 

 adaptation and adaptedness were regarded as among the 

 most fundamental phenomena of life. It was facts such 

 as these that furnished ammunition for Paley and a 

 whole succession of natural theologians. It was these 

 which Lamarck sought to explain by his theory of evolu- 

 tion through functional activity, and which Darwin at- 

 tributed to the action of natural selection. And it is in 

 this same realm of facts that the vitalists find their rea- 



1 In its main outlines, this paper was written about Ihv year. a-o. It was 

 submitted for publication February, 191 S, and .iinf thou h:i< tm,lrr-oiir 

 relatively little revision. For this reason, ado<|uate rrr.Mvn<-.. !ia< not Imvu 



