NATURAL SELECTION AND NATURAL THEOLOGY 257 



laws relating to specific gravity are at least of as much importance 

 in the economy of nature as are the general laws relating to spe- 

 cific differentiation ; and in each illustration alike [that is, in the 

 eye and in the separation and segregation of the sands of the 

 sea-beach] we find the result of the operation of known physical 

 causes to be that of selection. If it should be argued in reply 

 that the selective action in the one case is obviously purposeless, 

 while in the other it is as obviously purposive, I answer that this 

 is a pure assumption. It is, perhaps, not too much to say that 

 every geological formation on the face of the globe is either wholly 

 or in part due to the selective influence of specific gravity, and 

 who can say that the construction of the earth's crust is a less 

 important matter in the general scheme of things (if there is such 

 a scheme) than is the evolution of the eye? Or who shall say 

 that because we see an apparently intentional adaptation of means 

 to ends as the result of selection in the case of the eye, there is 

 no such intention served by the result of selection in the case of 

 the seaweeds, stones, sand, mud ? For anything that we know 

 to the contrary, the supposed intelligence may take a greater 

 delight in the latter than in the former process." 



While Romanes's reasoning is identical with that which I have 

 already quoted from Darwin, its failure to overthrow, or even 

 to fairly meet, Paley's argument is made all the more clear by 

 Romanes's more explicit statement of his difficulty; for Paley's 

 contention is not that the eye is designed in any way which may 

 not be equally true of nature as a whole, but that it gives peculiar 

 evidence of design. 



However we may have come by our eyes, we prize sight as 

 a most useful and precious endowment, and we know that the 

 adjustment between the mechanism of the eye and- the data of 

 optics is so useful to all who see that they may at any time owe 

 to it their lives ; while we are unable to attach any meaning to an 

 assertion that the course which the wind blows is useful to the 

 wind, whatever may be the unknown significance of either eye 

 or wind in the economy of nature as a whole. 



One may admit total ignorance of the significance, in the gen- 

 eral scheme of nature, of the skill of cats in catching mice; one 

 may fail to see how the way the grains of sand fall can be useful 



