In general, it is perfectly obvious that men do necessarily absorb, out of the influences in which they grow up, something which gives a complexion to their whole after-character. When historians have to relate great social or speculative changes, the overthrow of a monarchy or the establishment of a creed, they do but half their duty if they merely relate the events. In an account, for instance, of the rise of Mahometanism, it is not enough to describe the character of the Prophet, the ends which he set before him, the means which he made use of, and the effect which he produced; the historian must show what there was in the condition of the Eastern races which enabled Mahomet to act upon them so powerfully; their existing beliefs, their existing moral and political condition. In our estimate of the past, and in our calculations of the future--in the judgments which we pass upon one another, we measure responsibility, not by the thing done, but by the opportunities which people have had of knowing better or worse. In the efforts which we make to keep our children from bad associations or friends we admit that external circumstances have a powerful effect in making men what they are. But are circumstances everything? That is the whole question. A science of history, if it is more than a misleading name, implies that the relation between cause and effect holds in human things as completely as in all others, that the origin of human actions is not to be looked for in mysterious properties of the mind, but in influences which are palpable and ponderable. When natural causes are liable to be set aside and neutralised by what is called volition, the word Science is out of place. If it is free to a man to choose what he will do or not do, there is no adequate science of him. If there is a science of him, there is no free choice, and the praise or blame with which we regard one another are impertinent and out of place. I am trespassing upon these ethical grounds because, unless I do, the subject cannot be made intelligible. Mankind are but an aggregate of individuals--History is but the record of individual action; and what is true of the part, is true of the whole. We feel keenly about such things, and when the logic becomes perplexing, we are apt to grow rhetorical about them. But rhetoric is only misleading. Whatever the truth may be, it is best that we should know it; and for truth of any kind we should keep our heads and hearts as cool as we can.