148 DARWINIANA. 



theory is based, and even over-strictly insists, upon 

 the most universal of physiological laws, namely, that 

 successive generations shall differ only slightly, if at 

 all, from their parents ; and this effectively excludes 

 crude and impotent forms. Wherefore, if we believe 

 that the species were designed, and that natural prop- 

 agation was designed, how can we say that the actual 

 varieties of the species were not equally designed? 

 Have we not similar grounds for inferring design in 

 the supposed varieties of species, that we have in the 

 case of the supposed species of a genus ? When a nat- 

 uralist comes to regard as three closely-related species 

 what he before took to be so many varieties of one spe- 

 cies, how has he thereby strengthened our conviction 

 that the three forms are designed to have the differences 

 which they actually exhibit ? Wherefore, so long as 

 gradatory, orderly, and adapted forms in Nature argue 

 design, and at least while the physical cause of varia- 

 tion is utterly unknown and mysterious, we should 

 advise Mr. Darwin to assume, in the philosophy of his 

 hypothesis, that variation has been led along certain 

 beneficial lines. Streams flowing over a sloping plain 

 by gravitation (here the counterpart of natural selec- 

 tion) may have worn their actual channels as they 

 flowed; yet their particular courses may have been 

 assigned ; and where we see them forming definite 

 and useful lines of irrigation, after a manner unac- 

 countable on the laws of gravitation and dynamics, 

 we should believe that the distribution was designed. 

 To insist, therefore, that the new hypothesis of the 

 derivative origin of the actual species is incompatible 

 with final causes and design, is to take a position which 



