Now, these strongly pronounced favorable modifications are explicable only upon the theory of reversion. Had they arisen by the slow accumulation, through centuries, of successive, scarcely appreciable increments of modification, their being due to evolution, or solely to the physical conditions, would be less inconceivable. Darwin's professedly favorite rule is, Natura non facit saltum—"Nature makes no leaps." But we fail to see nature's conformity to it. We must confess that upon the hypothesis of evolution nature indulges herself with the most gigantic leaps.
It might be urged that, upon assuming, for the purposes of the argument, that Mr. Herbert Spencer does attribute variations solely to the physical conditions, he is thereby discharged from the imputation of advocating a theory which is wholly gratuitous. But he assuredly is not. He is placed by this ascription of variations in no better position, so far as respects this point. He has adduced no evidence in favor of their being thus solely ascribable. His attribution of them solely to the physical conditions is equally gratuitous with his ascription of them to evolution. The fact that variations are due to a change in the conditions, and that variations would be absent were all the individuals of a species subjected to absolutely uniform conditions, is, as we have seen, quite compatible with a belief in a concurrent cause. The necessity of a change in the conditions is admitted, and even called for, upon our theory. Mr. Herbert Spencer's assumed assertion of variation being due solely to mechanical causes would necessarily imply a denial of a concurrent cause. But this denial is wholly gratuitous; he has furnished no warrant for it. And again, assuming him to concede a concurrent cause, the question then recurs, Are variations attributable to reversion or to evolution? As we have seen, there is no foundation for ascribing them to evolution—evolution being merely a name for a cause unknown.
In The Westminster Review for July, 1865, and in The North American Review for October, 1868, Mr. Herbert Spencer is taxed with inconsistency. In his Principles of Biology, Mr. Spencer writes, "In whatever way it is formulated, or by whatever language it is obscured, this ascription of organic evolution to some aptitude naturally possessed, or miraculously imposed on them, is unphilosophical. It is one of those explanations which explains nothing—a shaping of ignorance into the semblance of knowledge. The cause assigned is not a true cause—not a cause assimilable to known causes—not a cause that can anywhere be shown to produce analogous effects. It is a cause unrepresentable in thought; one of those illegitimate symbolic conceptions which cannot by any mental process be elaborated into a real conception. In brief, this assumption of a persistent formative power, inherent in organisms, and making them unfold into higher forms, is an assumption no more tenable than the assumption of special creations; of which, indeed, it is but a modification, differing only by the fusion of separate unknown processes into a continuous unknown process." When he proceeds to treat of the waste and repair of the tissues, he finds that they refuse to acknowledge his mechanical principles, and he is forced to assume for the living particles "an innate tendency to arrange themselves into the shape of the organism to which they belong." The inconsistency was noted, commented upon, and became the subject of much animadversion.
This inconsistency, however, is comparatively excusable, as the histological phenomena which he had to explain are complicated and involved, and have to respond to the influences of divers parts of the body. But were we to show that his denunciation of the "ascription of organic evolution to some aptitude," is equally applicable to the attribution to "evolution," he would be considered, we are sure, guilty of the grossest possible inconsistency. This we can show; for there is no definition of a "metaphysical entity," to which the term evolution does not answer. Can any one conversant with the works of the first of evolutionists, particularly with his First Principles, Principles of Psychology, and Principles of Biology, gainsay the fact that organic evolution implies a tendency in organisms to advance, when under the influence of physical conditions, from the simpler to the more complex?
Mr. Spencer tacitly assumes the inevitable "becoming of all living things;" and that organic progress is a result of some indwelling tendency to develop, naturally impressed on living matter—some ever-acting constructive force, which, concurrently with other forces, moulds organisms into higher and higher forms. Many instances of this we might adduce, but we will quote but two. On page 403, of his First Principles, he speaks of "a tendency toward the differentiation of each race into several races." And on page 430, Vol. I. of his Principles of Biology, he says, "While we are not called on to suppose that there exists in organisms any primordial impulse which makes them continually unfold into more heterogeneous forms, we see that a liability to be unfolded arises from the action and reaction between organisms and their fluctuating environments."
Surely, it cannot, with any show of reason, be contended that the word "liability" is not here used as the perfect synonym of that "metaphysical entity," the word "tendency." If the concurrence of a "liability to be unfolded" and the physical conditions be the definition of evolution, were we not warranted in asserting all that we did, with respect to the implication of organic evolution? Evolution a "metaphysical entity"! The words seem strange. They sound like a contradiction in terms; and we know that it is hard to realize the fact that Mr. Spencer has based his whole theory upon "some aptitude." But can the fact be gainsaid? Do not the thoughts of every one who reads of a "liability to be unfolded," recur to the page where Mr. Spencer stigmatizes such phrases as unphilosophical? Hear again how he characterizes them. "In whatever manner it is formulated, or by whatever language it is obscured, this ascription of organic evolution to some aptitude naturally possessed, or miraculously imposed on them, is unphilosophical. It is one of those explanations which explains nothing—a shaping of ignorance into the semblance of knowledge." Every reader will, we are sure, concur with us in the opinion that the evolution hypothesis is here clearly condemned. The special creation theory, as here advocated, involves no occult factor. The physical conditions concur with reversion to cause the favorable modifications.
While we do not join in such a strong protest against the use of what are termed "metaphysical entities," as that in which positivists are wont to indulge, we cannot but concede that they have often retarded the progress of science, and directed the course of inquiry into wrong channels. But the true scientist does not altogether eschew their use; nor does science preclude his following a middle course. But that, however, against which we do most earnestly and most indignantly protest is their use for the purpose of showing incongruity between science and religion; and their use when there is a perfectly legitimate alternative. The advocates of evolution endeavor to laugh to scorn such phrases; but, double which way they will, they are forced to use them, if not in one instance, at least in another.
We hope, then, never again to hear "metaphysical entities" urged as an objection against the special creation theory. But we incline to retract that. For the positivists have become, through practice, so well conversant with the phraseology peculiar to this theme, that they are now capable of masterpieces of wit and eloquence. Were they, through fear of the imputation of inconsistency, to refrain from furnishing the world with these, we would be debarred the pleasure of their perusal. With reluctance would we forego such opportunities of cultivating a delicacy of taste.
In Appleton's Journal for July 31st, 1869, Mr. Spencer has declared that "the very conception of spontaneity is wholly incongruous with the conception of evolution." Now, to our mind, the theory of "spontaneous generation" is the perfect analogue of the theory of evolution. We conceive that the latter theory is open to the same objections which are urged by Mr. Spencer against the hypothesis of heterogenesis. "No form of evolution," he declares, "organic or inorganic, can be spontaneous, but in every instance the antecedent forces must be adequate in their quantities, kinds, and distributions to work the observed effects." Now, do not the alleged cases of evolution, equally with those of spontaneous generation, fail to fulfil this requirement? Does not Mr. Spencer's assumption of a tendency as a concurrent cause with the conditions, imply such a failure? What precludes the advocates of "spontaneous generation" from assuming "a liability" in inorganic matter "to unfold" into microscopic organisms? Could not agenesis have resulted from the concurrence of this tendency with mechanical causes? Such an explanation is equally open to the believers in "spontaneous generation." The true status of the evolution hypothesis is really no higher than that of the hypothesis of heterogenesis. They are both founded upon similar bases.
Together with the absurdity of adducing alleged cases of necrogenesis as the assumed missing link in the evolution process, might also have been mentioned, by Mr. Spencer, an objection to which the experiments of Professor Wyman are open. It is assumed in those experiments that, if fully matured organisms are not able to stand a temperature above two hundred and eight degrees, their ova would be destroyed when subjected to a temperature of two hundred and twelve degrees. These ova are allowed to stand only a little over three degrees more than a developed organism. Is this a fair supposition? Is it not to be expected that, if a fully matured organism can stand a temperature of two hundred and eight degrees, its ova, which are almost diatomic in character, will sustain a temperature approaching that of incandescence? We trust that this digression will be pardoned.