Creation or Evolution? A Philosophical Inquiry

by George Ticknor Curtis

4. Embryonic Development.—From the human ovule, which is said to differ in no respect from the ovule of other animals, into and through the early embryonic period, we are told that the embryo of man can hardly be distinguished from that of other members of the vertebrate kingdom. It is not necessary to repeat the details of the resemblance, which are undoubtedly striking, because they show a remarkable similarity between the embryo of man and that of the dog and the ape, in the earlier stage of the development, and that it is not until quite in the later stages of development that the three depart from each other, the difference between the young human being and the ape being not so great as that between the ape and the dog. We may, of course, accept Prof. Huxley's testimony that "the mode of origin [conception?] and the early stages of the development of man are identical with those of the animals immediately below him in the scale; without a doubt, in these respects, he is far nearer to the apes than the apes are to the dog."[48]

5. Rudiments.—This is a somewhat obscure branch of the proofs, which requires a more detailed examination in order to appreciate its bearing on the general theory of evolution. A distinction is made between rudimentary and nascent organs. The former are absolutely useless to their possessor—such as the mammæ of male quadrupeds, or the incisor teeth of ruminants, which never cut through the gums—or else they are of such slight service to their present possessors that they can not be supposed to have been developed under the conditions which now exist. These useless, or very slightly useful, organs in the human frame, are supposed to have been organs which had an important utility in the lower animals from which man is descended, but, by disuse at that period of life when the organ is chiefly used, and by inheritance at a corresponding period of life, they became of less and less utility in the successive animals that were evolved out of the preceding forms, until they sank into the condition of useless appendages, although perpetuated by force of the derivation of one species of animal from another, caused by the operation of the laws of natural and sexual selection. Nascent organs, on the other hand, are those which, though not fully developed to their entire capability, are of high service to their possessor, and may be carried to a higher degree of utility. One of the characteristics, as it is said, of rudimentary organs, is that they often become wholly suppressed in individuals, and then reappear occasionally in other individuals, through what is called reversion, or a return to ancestral peculiarities.[49] We are told that "not one of the higher animals can be named which does not bear some part in a rudimentary condition; and man forms no exception to the rule."[50]

Among the rudiments that are peculiar to man, and which are supposed to be proofs of his cognate relations to the lower animals, we are referred to certain muscles in a reduced condition, which in the other animals are used to move, twitch, or contract the skin, and remnants of which, in an efficient state, are found in various parts of our bodies; for instance, the muscles which raise the eyebrows, those which contract the scalp, those which, in some individuals, move the external ear, and similar muscular powers in different parts of the body. These are adduced as illustrations of the persistent transmission of an absolutely useless, or almost useless, faculty, "probably" derived from our remote semi-human progenitors. There is also another rudiment in man, found in the covering of the eye, and called by anatomists the "semi-lunar fold," which in birds is of great functional importance, as it can be rapidly drawn across the whole eyeball. In those animals in which, with its accessory muscles and other structures, it is well developed, as in some reptiles and amphibians, and in sharks, it is a third eyelid. In the two lower divisions of the mammalian series, the monotremata and the marsupials, and in some few of the higher mammals, as in the walrus, it is said to be fairly well developed. But in man, in the quadrumana, and most other mammals, it has become a mere rudiment.

The sense of smell in man is also classed by Darwin and other naturalists among the rudiments. It is argued that it was not originally acquired by man as he now exists, but that he has inherited this power, in an enfeebled and so far rudimentary condition, from some early progenitor, to whom it was highly serviceable, and by whom it was continually used.

Then we have the rudiment of hair, which, so far as it now exists on different parts of our body, is regarded as a mere remnant of the uniform hairy coat of the lower animals. Man, as he is now born, "differs conspicuously from all the other primates in being almost naked." But this nearly nude condition was not, it is said, the condition of his progenitors, and it is not the condition of his co-descendants from the same progenitors. At some time the progenitors of man and his co-descendants became covered all over with a coat of hair. What remains upon our bodies of this peculiar growth, that is called hair, is what was left after the agency of natural selection had worked off what was useless to the successive animals, and sexual selection had operated to transmit to offspring the absence of hair that had accrued in the nearer progenitors and the immediate parents. The illustrations which render this view "probable" do not need to be repeated, nor is it necessary to follow out the speculations concerning the mode in which our progenitors, near or remote, became varied in respect to the quantity, position, or direction of the hairs on various parts of their bodies.

There are several other alleged homologues or rudiments which are supposed to connect man with the lower animals, but which, whatever may be the resemblances, it is not necessary to discuss in detail, because there is one consideration at least which applies to the whole of this class of proofs, and to that I now pass. The three great classes of facts on which the whole argument rests, viewing man as an animal and omitting all reference to his intellect, are the resemblances of his bodily structure to that of the other mammals, the similarity between his embryonic development and theirs, and the rudiments. I reserve for separate discussion the counter-proof which may be derived from the nature of the human mind, and the special adaptation of the human structure to become the temporary residence and instrument of a spiritual and immortal being.

"It is," says Mr. Darwin, "no scientific explanation to assert that they have all [man and the other animals of the mammalian class] been formed on the same ideal plan."[51] The similarity of pattern is pronounced "utterly inexplicable" upon any other hypothesis than that all these animals are descended from a common progenitor, and that they have become what they are by subsequent adaptation to diversified conditions. I may incur some risk in undertaking to suggest what is a "scientific" explanation. Certainly I do not propose to "assert" anything. But I will endeavor to keep within the bounds of what I suppose to be science. I take that to be a scientific explanation which, embracing the important facts of natural history as the groundwork of the reasoning, undertakes to show the rationality of one hypothesis that differs from another, when the question is, Which has the greater amount of probability in its favor?

All correct reasoning on this subject of man's descent as an animal begins, I presume, with the postulate of an Infinite Creator, having under his power all the elements and forms of matter, organized and unorganized, animate and inanimate. There is no fundamental difference of opinion on this point, as I understand, between some of the evolutionists and their opponents.[52] Omnipotence, boundless choice of means and ends, illimitable wisdom, a benevolence that can not fail and can not err, are the conceded attributes of the being who is supposed to preside over the universe; and, however difficult it may be for us to express a conception of infinite power and infinite wisdom, as it is to describe infinite space and duration, we know what we mean to assume when we speak or think of faculties that are without limit, and of moral qualities that are subject to no imperfection. It is true that we have no means of forming an idea of superhuman and infinite power but by a comparison of our own limited faculties with those which we assume to belong to an eternal and infinite God. But the nature of our own limited powers teaches us that there may be powers that are as far above ours as the heavens are above the earth, as the endless realms of space stretch beyond and forever beyond any measurable distance, as eternity stretches beyond and forever beyond all measurable time. At all events, the postulate of an infinite God is the one common starting-point for the scientists of the evolution school and those who accept their doctrine, and for those who dissent from it. If I did not assume this, I could not go one step further, for without it there could not be a basis for any reasoning on the subject that would lead anywhere but to the conclusion that all that exists came by blind chance. This conclusion is rejected alike by the scientists, whose views I am now examining, and by those who differ from them.

In the economy of Nature, which is but another term for the economy of the Omnipotent Creator, there is no waste of power, as there is no abstention from the exercise of power, where its exertions are needed to accomplish an end. By this I mean that when a general plan of construction is found carried out through a variety of organizations, the rational inference is that so much power has been exerted as was needful to accomplish in each organization the objects that are common to all of them, and that no more power has been used in that direction. But where a special adaptation in some one variety of the same class of constructions is needful to accomplish an object peculiar to a new variety, the necessary amount of power never fails to be exerted. A study of the animal kingdom reveals this great truth, as palpably as a study of the products of human skill reveals the fact that man, from the imperfection of his faculties, is constantly exerting more or less power than was needful in his efforts to produce a new variety in his mechanical constructions. Experience and accumulated knowledge enable us to carry a general plan of construction through a considerable group of mechanical forms; but it is when we endeavor to vary the principle of construction so as to produce a new and special mode of operation, that we either waste power in repeating the general plan or fail to exercise the amount of power necessary to adapt the general plan to the introduction of the special object at which we are aiming. Our success in making such adaptations is often wonderful, but our failures evince that our imperfect faculties do not always enable us to accomplish the necessary adaptations of the general plan of construction to the special objects which we wish to attain. To the Infinite Creator, all such difficulties are unknown. He neither wastes power by new plans that are unnecessary, nor makes "vain repetitions," nor fails to exert the requisite amount of power and wisdom in the introduction of new and special contrivances which he ingrafts upon or superadds to the general plan, and which he has devised for the accomplishment of a new object. With a boundless choice of means and ends, with a skill that can not err, with a prescience that sees the end from the first conception of the design, he can repeat the general plan throughout any variety of constructions without any waste of power, and can introduce the new adaptations or contrivances which are to constitute a new construction, by the exercise of all the power that is required to accomplish a special object. Whether we are to suppose that he does this by the establishment of certain laws which he leaves to operate within prescribed limits, or does it by special creations proceeding from direct and specific exertions of his will, the question of his power to employ the one method or the other remains always the same. The question of which was his probable method depends upon the force of evidence; and upon this question we must allow great weight to the fact which all Nature discloses, namely, that the Creator does not waste power by making new plans of construction where an existing plan may be usefully repeated, and that he does not fail to exercise the necessary power when he wishes to add to the general plan of construction a new and special organism for a particular purpose.

Is there anything presumptuous in thus speaking of the determination and purposes of the Omnipotent Creator? We have his existence and infinite attributes conceded as the basis of all sound reasoning on his works. Why then should we not infer his purposes and his acts from his works? Why should we not attribute to him a special design, when we can not examine his works without inferring such special design, unless we conclude that the most amazing and peculiar constructions grew up under the operation of causes of which we have no sufficient proof, and in the supposed result of which there are admitted chasms that can not be bridged over?