414 Darwin, and after Darwin. 
whole sphere of such causation itself: therefore it lies 
beyond any possible intrusion by science. And not 
only so. But if the nature of natural causation be 
that of the highest order of known existence, then, 
although we must evidently be incapable of conceiving 
what such a Mind is, at least we seem capable of 
judging what in many respects it is not. It cannot 
be more than one; it cannot be limited either in 
space or time; it cannot be other than at least as 
self-consistent as its manifestations in nature are in- 
variable. Now, from the latter deduction there arises 
a point of first-rate importance in the present con- 
nexion. For if the so-called First Cause be intelligent, 
and therefore all secondary causes but the expression 
of a supreme Will, in as far as such a Will is self- 
consistent, the operation of all natural causes must 
be uniform,— with the result that, as seen by us, this 
operation must needs appear to be what we call 
mechanical. The more unvarying the Will, the more 
unvarying must be this expression thereof; so that, 
if the former be absolutely self-consistent, the latter 
cannot fail to be as reasonably interpreted by the 
theory of mindless necessity, as by that of ubiquitous 
intention. Such being, as it appears to me, the pure 
logic of the matter, the proof of organic evolution 
amounts to nothing more than the proof of a natural 
process. What mode of being is ultimately concerned 
in this process—or in what it is that this process 
ultimately consists—is a question upon which science 
is as voiceless as speculation is vociferous. 
But, it may still be urged, surely the principle of 
natural selection (with its terrible basis in the struggle 
for existence) and the principle of sexual selection 
