60 CREATIVE EVOLUTION [chap. 



in sexual generation; it has been interpreted in the most 

 diverse ways; and some very acute enquirers even regard 

 the sexuality of the plant, at least, as a luxury which nature 

 might have dispensed with. 1 But we do not wish to dwell 

 on facts so disputed. The ambiguity of the term " adapta- 

 tion," and the necessity of transcending both the point 

 of view of mechanical causality and that of anthropomor- 

 phic finality, will stand out more clearly with simpler 

 examples. At all times the doctrine of finality has laid 

 much stress on the marvellous structure of the sense- 

 organs, in order to liken the work of nature to that of an 

 intelligent workman. Now, since these organs are found, 

 in a rudimentary state, in the lower animals, and since 

 nature offers us many intermediaries between the pig- 

 ment-spot of the simplest organisms and the infinitely 

 complex eye of the vertebrates, it may just as well be 

 alleged that the result has been brought about by natural 

 selection perfecting the organ automatically. In short, 

 if there is a case in which it seems justifiable to invoke 

 adaptation, it is this particular one. For there may be 

 discussion about the function and meaning of such a thing 

 as sexual generation, in so far as it is related to the con- 

 ditions in which it occurs; but the relation of the eye to 

 light is obvious, and when we call this relation an adapta- 

 tion, we must know what we mean. If, then, we can show, 

 in this privileged case, the insufficiency of the principles 

 invoked on both sides, our demonstration will at once 

 have reached a high degree of generality. 



Let us consider the example on which the advocates 

 of finality have always insisted: the structure of such 

 an organ as the human eye. They have had no diffi- 



1 MObius, Beitrage zur Lehre von der Fortpflanzung der Gew'dchse, 

 Jena, 1897, pp. 203-206 in particular. Cf . Hartog, ' ' Sur les ph6nomenes 

 de reproduction" (Annee biologique, 1895, pp. 707-709). 



