not, Indeed, as we contemplate the actual direction of investigation and
speculation in the physical and natural sciences, we dimly apprehend a
probable synthesis of these divergent theories, and in it the ground for a
strong stand against mere naturalism. Even if the doctrine of the origin of
species through natural selection should prevail in our day, we shall not
despair; being confident that the genius of an Agassiz will be found equal
to the work of constructing, upon the mental and material foundations
combined, a theory of Nature as theistic and as scientific as that which he
has so eloquently expounded.

To conceive the possibility of "the descent of species from species by
insensibly fine gradations" during a long course of time, and to
demonstrate its compatibility with a strictly theistic view of the
universe, is one thing; to substantiate the theory itself or show its
likelihood is quite another thing. This brings us to consider what Darwin's
theory actually is, and how he supports it.

That the existing kinds of animals and plants, or many of them, may be
derived from other and earlier kinds, in the lapse of time, is by no means
a novel proposition. Not to speak of ancient speculations of the sort, it
is the well-known Lamarckian theory. The first difficulty which such
theories meet with is that in the present age, with all its own and its
inherited prejudgments, the whole burden of proof is naturally, and indeed
properly, laid upon the shoulders of the propounders; and thus far the
burden has been more than they could bear. From the very nature of the
case, substantive proof of specific creation is not attainable; but that of
derivation or transmutation of species may be. He who affirms the latter
view is bound to do one or both of two things: 1. Either to assign real and
adequate causes, the natural or necessary result of which must be to
produce the present diversity of species and their actual relations; or, 2.