20 THE DARWINIAN HYPOTHESIS i 



and that it is not contradicted by the main phen- 

 omena of life and organisation appear to us to be 

 unquestionable ; and, so far, it must be admitted to 

 have an immense advantage over any of its prede- 

 cessors. But it is quite another matter to affirm 

 absolutely either the truth or falsehood of Mr. 

 Darwin's views at the present stage of the inquiry. 

 Goethe has an excellent aphorism defining that 

 state of mind which he calls " Thatige Skepsis " 

 active doubt. It is doubt which so loves truth 

 that it neither dares rest in doubting, nor extin- 

 guish itself by unjustified belief; and we commend 

 this state of mind to students of species, with 

 respect to Mr. Darwin's or any other hypothesis, 

 as to their origin. The combined investigations 

 of another twenty years may, perhaps, enable 

 naturalists to say whether the modifying causes 

 and the selective power, which Mr. Darwin has 

 satisfactorily shown to exist in Nature, are com- 

 petent to produce all the effects he ascribes to 

 them ; or whether, on the other hand, he has been 

 led to over-estimate the value of the principle of 

 natural selection, as greatly as Lamarck over- 

 estimated his vera causa of modification by exercise. 

 But there is, at all events, one advantage pos- 

 sessed by the more recent writer over his pre- 

 decessor. Mr. Darwin abhors mere speculation as 

 nature abhors a vacuum. He is as greedy of cases 

 and precedents as any constitutional lawyer, and 

 all the principles he lays down are capable of being 



