And so of religion. Though the forms it has assumed and the animosities it has aroused have often sundered men and produced warfare, yet it has at other times been the means of promoting association. A common worship has often, as among the Greeks, mitigated war and furnished the basis of union, while it is from the triumph of Christianity over the barbarians of Europe that modern civilization springs. Had not the Christian Church existed when the Roman Empire went to pieces, Europe, destitute of any bond of association, might have fallen to a condition not much above that of the North American Indians or only received civilization with an Asiatic impress from the conquering scimiters of the invading hordes which had been welded into a mighty power by a religion which, springing up in the deserts of Arabia, had united tribes separated from time immemorial, and, thence issuing, brought into the association of a common faith a great part of the human race.

Looking over what we know of the history of the world, we thus see civilization everywhere springing up where men are brought into association, and everywhere disappearing as this association is broken up. Thus the Roman civilization, spread over Europe by the conquests which insured internal peace, was overwhelmed by the incursions of the northern nations that broke society again into disconnected fragments; and the progress that now goes on in our modern civilization began as the feudal system again began to associate men in larger communities, and the spiritual supremacy of Rome to bring these communities into a common relation, as her legions had done before. As the feudal bonds grew into national autonomies, and Christianity worked the amelioration of manners, brought forth the knowledge that during the dark days she had hidden, bound the threads of peaceful union in her all-pervading organization, and taught association in her religious orders, a greater progress became possible, which, as men have been brought into closer and closer association and co-operation, has gone on with greater and greater force.

But we shall never understand the course of civilization, and the varied phenomena which its history presents, without a consideration of what I may term the internal resistances, or counter forces, which arise in the heart of advancing society, and which can alone explain how a civilization once fairly started should either come of itself to a halt or be destroyed by barbarians.

The mental power, which is the motor of social progress, is set free by association, which is,—what, perhaps, it may be more properly called,—an integration. Society in this process becomes more complex; its individuals more dependent upon each other. Occupations and functions are specialized. Instead of wandering, population becomes fixed. Instead of each man attempting to supply all of his wants, the various trades and industries are separated—one man acquires skill in one thing, and another in another thing. So, too, of knowledge, the body of which constantly tends to become vaster than one man can grasp, and is separated into different parts, which different individuals acquire and pursue. So, too, the performance of religious ceremonies tends to pass into the hands of a body of men specially devoted to that purpose, and the preservation of order, the administration of justice, the assignment of public duties and the distribution of awards, the conduct of war, etc., to be made the special functions of an organized government. In short, to use the language in which Herbert Spencer has defined evolution, the development of society is, in relation to its component individuals, the passing from an indefinite, incoherent homogeneity to a definite, coherent heterogeneity. The lower the stage of social development, the more society resembles one of those lowest of animal organisms which are without organs or limbs, and from which a part may be cut and yet live. The higher the stage of social development, the more society resembles those higher organisms in which functions and powers are specialized, and each member is vitally dependent on the others.

Now, this process of integration, of the specialization of functions and powers, as it goes on in society, is, by virtue of what is probably one of the deepest laws of human nature, accompanied by a constant liability to inequality. I do not mean that inequality is the necessary result of social growth, but that it is the constant tendency of social growth if unaccompanied by changes in social adjustments, which, in the new conditions that growth produces, will secure equality. I mean, so to speak, that the garment of laws, customs, and political institutions, which each society weaves for itself, is constantly tending to become too tight as the society develops. I mean, so to speak, that man, as he advances, threads a labyrinth, in which, if he keeps straight ahead, he will infallibly lose his way, and through which reason and justice can alone keep him continuously in an ascending path.

For, while the integration which accompanies growth tends in itself to set free mental power to work improvement, there is, both with increase of numbers and with increase in complexity of the social organization, a counter tendency set up to the production of a state of inequality, which wastes mental power, and, as it increases, brings improvement to a halt.

To trace to its highest expression the law which thus operates to evolve with progress the force which stops progress, would be, it seems to me, to go far to the solution of a problem deeper than that of the genesis of the material universe—the problem of the genesis of evil. Let me content myself with pointing out the manner in which, as society develops, there arise tendencies which check development.

There are two qualities of human nature which it will be well, however, to first call to mind. The one is the power of habit:—the tendency to continue to do things in the same way; the other is the possibility of mental and moral deterioration. The effect of the first in social development is to continue habits, customs, laws and methods, long after they have lost their original usefulness, and the effect of the other is to permit the growth of institutions and modes of thought from which the normal perceptions of men instinctively revolt.

Now the growth and development of society not merely tend to make each more and more dependent upon all, and to lessen the influence of individuals, even over their own conditions, as compared with the influence of society; but the effect of association or integration is to give rise to a collective power which is distinguishable from the sum of individual powers. Analogies, or, perhaps, rather illustrations of the same law, may be found in all directions. As animal organisms increase in complexity, there arise, above the life and power of the parts, a life and power of the integrated whole; above the capability of involuntary movements, the capability of voluntary movements. The actions and impulses of bodies of men are, as has often been observed, different from those which, under the same circumstances, would be called forth in individuals. The fighting qualities of a regiment may be very different from those of the individual soldiers. But there is no need of illustrations. In our inquiries into the nature and rise of rent, we traced the very thing to which I allude. Where population is sparse, land has no value; just as men congregate together, the value of land appears and rises—a clearly distinguishable thing from the values produced by individual effort; a value which springs from association, which increases as association grows greater, and disappears as association is broken up. And the same thing is true of power in other forms than those generally expressed in terms of wealth.

Now, as society grows, the disposition to continue previous, social adjustments tends to lodge this collective power, as it arises, in the hands of a portion of the community; and this unequal distribution of the wealth and power gained as society advances tends to produce greater inequality, since aggression grows by what it feeds on, and the idea of justice is blurred by the habitual toleration of injustice.