§ 3. Application of these Criteria to Man.

When we come to apply these several criteria to the human race, it is found beyond dispute that they all concur in proving that the whole human family are of one and the same species. In the first place the corporeal frame or external structure is the same in all the varieties of the race. There is the same number of bones in the skeleton; their arrangement and disposition are the same. There is the same distribution of the blood-vessels. The brain, the spinal marrow, and the nervous system are the same in all. They all have the same muscles amounting to many thousand in number. The organs for breathing, respiration, digestion, secretion, and assimilation, are the same in all. There are indeed indefinite diversities in size, complexion, and character, and colour of the hair, within the same variety of the race, and between the varieties themselves. Some of these diversities are variable, and some are fixed. The Caucasian, the Mongolian, the African, have each their peculiarities by which the one is easily distinguished from the other, and which descend from generation to generation without alteration. With regard to these peculiarities, however, it is to be remarked, first, that they are less important and less conspicuous than those which distinguish the different varieties of domestic animals all belonging to the same species. No two men, or no men of different races, differ from each other so much as the little Italian greyhound and the powerful mastiff or bull-dog. And secondly, none of these peculiarities are indicative of difference of design, or plan, and therefore they are not indicative of difference in the immaterial principle, which according to the naturalists of the highest class, determines the identity of species and secures its permanence. And thirdly, these peculiarities are all referrible to the differences of climate, diet, and mode of life, and to the effect of propagation in case of acquired peculiarities. The truth of this last statement as to the influence of these several causes in modifying and perpetuating varieties in the same species, is abundantly illustrated and confirmed in the case of all the lower animals. Such is the sameness of all the varieties of mankind as to their corporeal structure, that a system of anatomy written in Europe and founded on the examination of the bodies of Europeans exclusively, would be as applicable in Asia, Africa, America, and Australia, as in Europe itself.

The second criterion of sameness of species is to be sought in the φύσις, or physical nature. In this respect also all mankind are found to agree, so that the physiology of the Caucasian, Mongolian, and African is precisely the same. The laws which regulate the vital processes are the same in all; respiration, digestion, secretion, and propagation, are all conducted in the same way in every variety of the species.

The third criterion is found in the ψυχή or psychological nature. This, as we have seen, is the highest test, for the ψυχή or immaterial principle is the most important element in the constitution of every living creature. Where that is the same, the species is the same. There can be no reasonable doubt that the souls of all men are essentially the same. They not only have in common all the appetites, instincts, and passions, which belong to the souls of the lower animals, but they all share in those higher attributes which belong exclusively to man. They all are endowed with reason, conscience, and free agency. They all have the same constitutional principles and affections. They all stand in the same relation to God as spirits possessing a moral and religious nature.

The fourth criterion is permanence, and the ability of indefinite propagation. We have seen that it is a law of nature, recognized by all naturalists (with a few recent exceptions), that animals of different species do not cohabit, and cannot propagate. Where the species are nearly allied, as the horse and the ass, they may produce offspring combining the peculiarities of both parents. But there the process stops. Mules cannot continue the mongrel race. It is however an admitted fact that men of every race, Caucasian, Mongolian, and African, can thus cohabit, and their offspring can be indefinitely propagated and combined. “Were these units [species],” says Professor Dana,¹⁰⁷¹⁰⁷Bibliotheca Sacra, 1857, p. 863. capable of blending with one another indefinitely, they would no longer be units, and species could not be recognized. The system of life would be a maze of complexities; and whatever its grandeur to a being that could comprehend the infinite, it would be unintelligible chaos to man. . . . It would be to man the temple of nature fused over its whole surface, and through its structure, without a line the mind could measure or comprehend.” As therefore the universe is constructed on a definite plan; as its laws are uniform; and as the constituent elements of the material world are permanent, it would be in strange contradiction with this universal analogy, if in the highest department of nature, in the organic and living world, 88everything should be unstable, so that species could mingle with species, and chaos take the place of order and uniformity. As therefore the different varieties of men freely unite and produce offspring permanently prolific, all those varieties must belong to one and the same species, or one of the most fixed of the laws of nature, is in their case reversed.

The Evidence of Identity of Race Cumulative.

It is to be observed that the strength of this argument for the unity of the human race does not depend upon any one of the above mentioned particulars separately. It is rather in their combination that the power of the argument lies. It is not simply because the corporeal structure is essentially the same in all men; nor simply because they have all the same physical, or the same psychological nature; or that they are capable of producing permanently prolific offspring; but because all these particulars are true in respect to the whole human family wherever found and through the whole course of its history. It becomes a mere matter of logomachy to dispute whether men are of the same species, if they have the same material organism, the same φύσις and the same ψυχή. Whether of the same species or not, if these things be admitted which cannot be rationally denied, they are of the same nature, they are beings of the same kind. Naturalists may give what meaning they please to the word species. This cannot alter the facts of the case. All men are of the same blood, of the same race, of the same order of creation.

“That the races of men,” says Delitzsch, “are not species of one genus, but varieties of one species, is confirmed by the agreement in the psychological and pathological phenomena in them all, by similarity in the anatomical structure, in the fundamental powers and traits of the mind, in the limits to the duration of life, in the normal temperature of the body and the average rate of pulsation, in the duration of pregnancy, and in the unrestricted fruitfulness of marriages between the various races.”¹⁰⁸¹⁰⁸Commentary on Genesis.