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THE AMERICAN NATURALIST [Vol. XLVII 



analyze our problems, the evidence offered in the opposite 

 direction is just as conspicuously positive and consists 

 of cases which have already been subjected to relatively 

 complete analysis. As Cowles 1 has pointed out, there has 

 never been any retrogression in these matters; all phe- 

 nomena now explained non-teleolgically were once ex- 

 plained teleologically, but no non-teleological explanation 

 once attained, has ever been replaced by one involving 

 purpose. Under these circumstances, a pragmatic judg- 

 ment must be rendered, at least tentatively, in favor of 

 the position here taken, that teleological thinking should 

 have, and will at length have, no place in our science at all. 



Conclusion. — I think it is to be concluded from the con- 

 siderations here set forth that there is nothing known of 

 the nature of living things which should lead the bio- 

 logical sciences to base their inquiries on any other 

 methods or modes of thought than those employed in the 

 sciences of the non-living. In both its aspects, passive 

 and active, the dominance of the concept of adaptation, 

 which now distinguishes our science from the non-bio- 

 logical ones, is related to the comparatively youthful 

 stage of development so far attained by biology, and not 

 to any observed character of the living objects with which 

 we deal. It seems obvious that biology is advancing 

 slowly but steadily along the path already traversed by 

 the other natural sciences, and I think our present opera- 

 tions may best be guided by the hypothesis that all these 

 sciences will eventually come to deal with the same funda- 

 mental concepts and modes of thought. Should this con- 

 dition of affairs ever come to actual attainment, then the 

 discussions which now center about the idea of adapta- 

 tion might be expected to give place to other discussions 

 of causal relations between measured qualities and prop- 

 erties of the objects dealt with, such as are already begin- 

 ning to be common in many lines of biological study. 



Bowles, H. C, in Coulter, Barnes and Cowles, "Text-book of Botany," 

 2: 948. 1911. 



