Variation and Natural Selection have their Struggle and consequent Check, or are limited by something inherent in the constitution of organic beings.  We are disposed to rank the derivative hypothesis in its fulness with the nebular hypothesis, and to regard both as allowable, as not unlikely to prove tenable in spite of some strong objections, but as not therefore demonstrably true.  Those, if any there be, who regard the derivative hypothesis as satisfactorily proved must have loose notions as to what proof is.  Those who imagine it can be easily refuted and cast aside must, we think, have imperfect or very prejudiced conceptions of the facts concerned and of the questions at issue.

We are not disposed nor prepared to take sides for or against the new hypothesis, and so, perhaps, occupy a good position from which to watch the discussion, and criticize those objections which are seemingly inconclusive.  On surveying the arguments urged by those who have undertaken to demolish the theory, we have been most impressed with a sense of their great inequality.  Some strike us as excellent and perhaps unanswerable; some, as incongruous with other views of the same writers; others, when carried out, as incompatible with general experience or general beliefs, and therefore as proving too much; still others, as proving nothing at all:  so that, on the whole, the effect is rather confusing and disappointing.  We certainly expected a stronger adverse case than any which the thorough-going opposers of Darwin appear to have made out.  Wherefore, if it be found that the new hypothesis has grown upon our favor as we proceeded, this must be attributed not so much to the force of the arguments of the book itself as to the want of force of several of those by which it has been assailed.  Darwin’s arguments we might resist or adjourn; but some of the refutations of it give us more concern than the book itself did.

These remarks apply mainly to the philosophical and theological objections which have been elaborately urged, almost exclusively by the American reviewers.  The “North British” reviewer, indeed, roundly denounces the book as atheistical, but evidently deems the case too clear for argument.  The Edinburgh reviewer, on the contrary, scouts all such objections,—­as well he may, since he records his belief in “a continuous creative operation,” “a constantly operating secondary creational law,” through which species are successively produced; and he emits faint, but not indistinct, glimmerings of a transmutation theory of his own;[1] so that he is equally exposed to all the philosophical objections advanced by Agassiz, and to most of those urged by the other American critics, against Darwin himself.

Proposing now to criticize the critics, so far as to see what their most general and comprehensive objections amount to, we must needs begin with the American reviewers, and with their arguments adduced to prove that a derivative hypothesis ought not to be true, or is not possible, philosophical, or theistic.