20 THE DARWINIAN HYPOTHESIS te 
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 abhorsa vacuum. He is as greedy of cases 
and precedents as any constitutional lawyer, and 
all the principles he lays down are capable of being 
