enable Evolution in general to result in continuous increase of structural and functional complexity. The present case is, indeed, but a special form of the more general case. How to secure a compromise between fluidity and rigidity is in both cases the essential desideratum. Where the units which make up the aggregate have too much individual freedom of motion, the result is a fluid state in which there is no chance for stable structural arrangements. Where they have too little freedom of motion, the result is a solid state in which there is no chance for structural rearrangements. In the first case, where there is so little dissipation of motion, there is little or no Evolution. In the second case, where so little internal motion is retained, the Evolution which occurs is simply or chiefly a process of consolidation, unattended by any considerable advance from indeterminate uniformity toward determinate multiformity.

Bearing in mind that we are dealing, not with a mere series of striking analogies, but with a group of real resemblances which result from a fundamental homology between the special process here considered and the more general process which includes it, let us observe that one chief circumstance which secures mobility without loss of coherence is a heterogeneous and ever-changing social environment, to the heterogeneous changes of which the community is continually required to adjust itself. The illustrations above given unite in showing that where circumstances have afforded such a heterogeneous environment (as a perpetual external excitant of internal rearrangements), the communities which have survived through relatively-complete adjustment have manifested a permanent capacity for progress. Thus is our problem completely connected with the more general problem of natural selection, and with the most general problem of Evolution as manifested in all orders of phenomena. And thus the essential continuity of the processes of Nature is again strikingly illustrated.

In the following chapter we shall have frequent occasion to refer to this circumstance of heterogeneity of the social environment as manifested psychologically, in its effects upon the intellectual mobility of men regarded as individuals. To pursue the problem of progressiveness into this psychological region is the way in which to obtain a basis for the explanation of the progress from Brute to Man; and to this crowning inquiry we must now address ourselves.

CHAPTER XXI.

GENESIS OF MAN, INTELLECTUALLY.

THE chief difficulty which most persons find in accepting the Doctrine of Evolution as applied to the origin of the human race, is the difficulty of realizing in imagination the kinship between the higher and the lower forms of intelligence and emotion. And this difficulty is enhanced by a tendency of which our daily associations make it hard to rid ourselves. There is a tendency to exaggerate the contrasts which really exist, by leaving out of mind the intermediate phenomena and considering only the extremes. Many critics, both among those who are hostile to the development theory and among those who regard it with favour, habitually argue as if the intelligence and morality of the human race might be fairly represented by the intelligence and morality of a minority of highly organized and highly educated people in the most civilized communities. When speaking of mankind they are speaking of that which is represented to their imagination by the small number of upright, cultivated, and well-bred people with whom they are directly acquainted, and also to some extent by a few of those quite exceptional men and women who have left names recorded in history. Though other elements are admitted into the conception, these are nevertheless the ones which chiefly give to it its character. Employing then this conception of mankind, abstracted from

these inadequate instances, our critics ask us how it is possible to imagine that a race possessed of such a godlike intellect, such a keen aesthetic sense, and such a lofty soul, should ever have descended from a race of mere brutes. And again they ask us how can a race endowed with such a capacity for progress be genetically akin to those lower races of which even the highest show no advance from one generation to another. Confronted thus by difficulties which reason and imagination seem alike incompetent to overcome, they too often either give up the problem as insoluble, or else— which amounts to nearly the same thing-have recourse to the deus ex machind as an aid in solving it.

Influenced, no doubt, by some such mental habit as this, Mr. St. George Mivart declares that, while thoroughly agreeing with Mr. Darwin as to man's zoological position, he nevertheless regards the difference between ape and mushroom as less important than the difference between ape and man, so soon as we take into the account "the totality of man's being." In this emphatic statement there is a certain amount of truth, though Mr. Mivart is not justified in implying that it is a truth which the Darwinian is bound not to recognize. The enormous difference between civilized man and the highest of brute animals is by no one more emphatically recognized than by the evolutionist, who holds that to the process of organic development there has been superadded a stupendous process of social development, and who must therefore admit that with the beginning of human civilization there was opened a new chapter in the history of the universe, so far as we know it. From the human point of view we may contentedly grant that, for all practical purposes, the difference between an ape and a mushroom is of less consequence than the difference between an ape and an educated European of the nineteenth century. But to take this educated European as a typical sample of mankind,

1 Nature, April 20, 1871.

and to contrast him directly with chimpanzees and gibbons, is in the highest degree fallacious; since the proceeding involves the omission of a host of facts which, when taken into the account, must essentially modify the aspect of the whole case.

When we take the refined and intellectual Teuton, with his one hundred and fourteen cubic inches of brain, and set him alongside of the chimpanzee with his thirty-five cubic inches of brain, the difference seems so enormous as to be incompatible with any original kinship. But when we interpose the Australian, whose brain, measuring seventy cubic inches, comes considerably nearer to that of the chimpanzee than to that of the Teuton, the case is entirely altered, and we are no longer inclined to admit sweeping statements about the immeasurable superiority of man, which we may still admit, provided they are restricted to civilized man. If we examine the anatomical composition of these brains, the discovery that in structural complexity the Teutonic cerebrum surpasses the Australian even more than the latter surpasses that of the chimpanzee, serves to strengthen us in our position. And when we pass from facts of anatomy to facts of psychology, we obtain still further confirmation; for we find that the difference in structure is fully paralleled by the difference in functional manifestation. If the Englishman shows such wonderful command of relations of space, time, and number, as to be able to tell us that to an observer stationed at Greenwich on the 7th of June, A.D. 2004, at precisely nine minutes and fifty-six seconds after five o'clock in the morning, Venus will begin to cross the sun's disc; on the other hand, the Australian is able to count only up to five or six, and cannot tell us the number of fingers on his two hands, since so large a number as ten excites in him only an indefinite impression of plurality. Our conception of

1 The Dammaras, according to Mr. Galton, are even worse off than this. "When they wish to express four, they take to their fingers, which are to