fill our minds with all the knowledge that may ever be possibly useful. A library is an external and materialised memory. But without illustrating so plain a point any further, I simply take note of what it implies: that is, that, as Professor Huxley has pointed out, all that distinguishes the present state of things from the state of things in the time of Elizabeth, or, perhaps, at the time of remote Egyptian dynasties, may be due, not to any change in the individual, but to what is called the social factor. The inference from the individual to the society, or from the society to the individual, is, therefore, rigidly impossible, because, given the man, the position in which he is placed and the stage of development of the society to which he belongs, are relevant facts which exercise an incalculably great influence.

If this be true, what follows? We remark, in the first place, that the evolution of which we speak in regard to natural history, the process by which the present population of the globe has gradually grown out of the population of remote geological epochs, is slow. The changes which it may produce are not sensible within a generation—for, indeed, the very nature of the case implies that they must take many generations—not perhaps even within such a period as is covered by all authentic history. It is not, of course, on that account to be overlooked for scientific purposes. Monkeys must have grown into men before they could begin to accumulate capital, either material or spiritual. The faculty of accumulating must itself have been developed. Only when once it was developed, another process would begin, the process of social evolution, which, however it may resemble the other, or possibly be in some sense its continuation, proceeds, at least, at a totally different rate. The difference is comparable, one may say roughly, to the difference between the speed of an express train and the speed of a four-wheeled waggon. Beneath the surface, it may be, the slower process is still continuing; men, for anything I can say to the contrary, may be acquiring larger brains and more sensitive bodies; and it is further possible, or rather obvious, that if we can do anything to facilitate this proceeding, to behave so as to give nature a better chance of turning out better work, we ought to do so. Only nature is pretty sure to take her time about it. How far, again, one process is to be considered as a continuation of the other, or as a modification, or even as in opposition to it, is a point which I cannot now touch. What I have to say is simply this: that if we take any two periods of society, the present, for example, and that of a thousand or five thousand years ago, we shall find enormous or incalculably great differences in the social structure, in the amount of knowledge, in the character of the ethical, religious, and philosophical beliefs, and in the relations between the individuals of which the society is constructed; but between the individuals at the two periods we may find hardly any definable difference whatever. For anything we can say, we should be able, if we could move people about in time as well as in space, to exchange a thousand infants of the nineteenth century A.D., for a thousand of the nineteenth century B.C., and nobody would be able to detect the difference which would result.

Hence it follows, in my opinion, that the evolutionary process with which moralists and political philosophers have practically to deal, is what I have called the social, and not the individual process. We inherit thoughts as we inherit wealth; we inherit customs and laws and forms of worship, and indeed our whole mental furniture; we can add enormously to our inheritance, and can transmit the augmented fund to our descendants. But the other process of inheritance, to which the word "heredity" is taken to apply, is not, immediately at least, cumulative. We inherit the old faculties, bodily and mental, unaltered, or with infinitesimal alterations, though we live in a different environment, and are ourselves as much altered as our environment. The modern social organism is built up, if I may say so, of cells almost identical in their properties with those of the old organism, although the mode of combination gives entirely new properties to the whole, and brings out new actions and reactions among the constituent cells themselves.

I have been touching the edge of certain problems of great interest but enormous complexity, and I shall venture to indicate the difference between these views and some which have recently attracted much attention. Mr. Kidd's work upon "Social Evolution" has made the phrase popular; but, instead of using it in my sense, he speaks as though "social evolution" involved what I have called individual evolution. In order to keep within limits, I will confine myself to one case upon which he lays great stress. It will show sufficiently why I hold his mode of reasoning to be inconclusive. Mr. Kidd has achieved success by very excellent qualities, by remarkable literary ability, and by his uniformly high tone of moral feeling. I should, therefore, be very sorry to speak of him otherwise than respectfully. Mr. Kidd, however, chooses to maintain a thesis in which he has certainly no personal interest,—the thesis, namely, that a little stupidity may be a very good thing. This view is, perhaps, intelligible when we observe that he also maintains that the progress of the race depends upon its holding "ultra-rational," which I think he would find it hard to distinguish from "irrational," beliefs. In support of this view he writes a chapter to prove that "progress is not primarily intellectual". The argument of which I have spoken is part of this proof. The Greeks, he tells us, were a race intellectually superior to ourselves. They were, so Mr. Galton informs him, two degrees above modern Englishmen in the scale of intelligence, and as superior to us as we are to the negro. And yet, says Mr. Kidd, this marvellous race died out, and no trace of its blood is now to be found in the present population of the world. Let us look shortly into the logic of this argument, and consider how far it is entitled to be regarded as scientific reasoning.

First of all, I should ask, what precisely is meant by "the Greeks"? The argument is founded partly on the number of great thinkers, poets, and artists, in proportion to the population. Now, it is obviously essential to a scientific statement that we should know what is the population indicated. If we compare the number of great men at Athens in its best period with the number of free Athenians, we shall get one ratio; if we admit the Athenian slaves, or add Bœotia and other Greek States to our population, we get quite a different ratio. And the difference is of immense importance. The smaller the population, the higher the excellence indicated by a given number of great men; but, also, the smaller the population, the less is the wonder that it should have died out or been swallowed up in the whirlpools of political, religious, and social convulsions. A similar remark applies in regard to the period during which this race flourished. When did they begin and when did they cease to be superior to other people? Till the statement is more precise we do not even know what are the phenomena to be explained; and the case is susceptible of any number of explanations. Did the superior race cease to be prolific; or was it prolific, but of inferior descendants; and, if so, was it because it was mixed with races of an inferior stamp; or was it because its position exposed it to the attacks of more numerous enemies; or because its energy led it to attempt