CHAPTER I

THE HUMAN TYPE OF EVOLUTION

VIEWED as an animal, man shows two striking phenomena: first, dispersal over all the varieties of earthly environment as no other animal is dispersed; and, second, a homogeneity so thoroughgoing that it is impossible to distinguish human species, let alone genera and other wider categories. The widest diversity of environment; the narrowest similarity of structure. At best only sub-species or varieties are definable, and even here there is such disagreement among classifiers as to lend great confusion to the study of ethnology. And the likenesses between men which baffle the classifier are not alone to be found as between human beings separated in space over the earth, but also as between those existing in different epochs of time. The Egyptian records and the diluvial remains unite in proclaiming the absence of radical diversity over the ages. In short, the influence of diverse

environment and the passing of much time fail to exhibit man as an animal much modified in visible structure as the result of adaptation.

However, if we survey the groups of mankind scattered up and down the earth, and consequently subject to the most diverse influences of natural environment, we find them differing widely from one another in their cultural response to surrounding physical conditions. But this implies a mental reaction on experience rather than an adaptation of a physical order. The fact is that whatever structural modification there is has been made in the brain, and that the rapidity and success of brain-adaptation has rendered bodily change unnecessary, thus freeing man from the inevitable process as seen among plants and animals, and as in them productive of structural characters which are utilized successfully by botanists and zoölogists in their classifications. Very likely actual structural changes are registered in the brain; of some of these scientists have an inkling, and others may sometime be observ

1 "The true difference of mankind,” says Count Okuma, as reported in the New York Times for October 4, 1914, "is neither in the color of the skin nor in the frame of the body, but is, if any, in the degree of culture itself. It is this difference that distinguishes winner and loser in the struggle for existence."

able with the perfecting of scientific instruments and methods.

At present, however, we are driven to a roundabout method of estimating these brain changes. Mental changes emerge in the form of ideas, and these are capable of materialization or realization. The complicated machine is the materialization of the brain-action of its inventors; it is not mere wood and iron. Every weapon, article of clothing, or other invention (standing as a substitute for structural modification) is in a very literal sense an idea materialized or made real; so are all systems and economies in society in a word, all human institutions. The stage in which a people is, in respect to the quantity and quality of its realized ideas, is called its stage of culture or civilization. The height of a society's civilization thus becomes a measure of its members' success in mental adaptation to the environment in which it lives.

Physical adaptations can be observed, described, explained, and classified along the lines of an evolutionary series. So can mental adaptations, though less directly. If races cannot yet be classified as a result of the study of the cerebrum itself, they can be classified on

the criterion of the activity of that organ, as displayed in the sum of materialized or realized ideas. Hence the study of the course of civilization, or of that of one of its factors, is as much a study in evolution as is the investigation of the phases through which general vertebrate structure, or the horse's hoof, proceeds. The mode of evolution is changed; the process goes on.

Thus human evolution diverges from the general course of antecedent evolution. But it is not right to say that all human evolution is mental, nor that mental evolution is absent in the animal. The facts support no such position-to occupy which would be to deny the validity of the whole evolutionary theory, as applied to man, by introducing an impassable period, barren of transitions, at some point; it would be to reaffirm the old-time catastrophic theory. Mental and physical adaptation cannot be exclusive of one another; the two are linked together, as has been intimated. "Brain and mind are reacting upon bone and muscle and

1

1 "If," says Darwin (“Origin of Species,” p. 174), “it could be demonstrated that any complex organ existed, which could not possibly have been formed by numerous, successive, slight modifications, my theory would absolutely break down." Absence of transitions anywhere thus breaks the course of evolution.

subduing and moulding them to their own mental ends. They are making of the body a fitter expression of the higher mental life. The body is becoming an expression of thought. Muscles of speech and expression are more effective and really more powerful than those of back and legs" and so are fit criteria for natural selection. But for the present purpose there is more to be gained by passing over the slight observable physical adaptations in man and concentrating attention upon the typical human mode upon the succession of mental adaptations to be seen in the course of civilization.

Human adaptation is thus typically of a mental order. But it is not of one mind or of a few minds. No civilization (sum or synthesis of mental adaptations) of any importance can be developed by individual or by limited group, in isolation. There must be contact and conflict of ideas, that their variations may be sifted out and a residue of superior adaptations preserved. Civilization is a function of numbers and of the contact of numbers. Human adaptation is therefore social as well as mental.

1 Tyler, "Man in the Light of Evolution," pp. 38-39.