“What is this talk,” I wrote, “which is made about the experience of the race, as though the experience of one man could profit another who knows nothing about him? If a man eats his dinner it nourishes him and not his neighbour; if he learns a difficult art it is he that can do it and not his neighbour” (“Life and Habit,” p. 49). When I wrote thus in 1877, it was not generally seen that though the father is not nourished by the dinners that the son eats, yet the son was fed when the father ate before he begot him. “Is there any way,” I continued, “of showing that this experience of the race about which so much is said without the least attempt to show in what way it may, or does, become the experience of the individual, is in sober seriousness the experience of one single being only, who repeats on a great many different occasions, and in slightly different ways, certain performances with which he has already become exceedingly familiar?” I felt, as every one else must have felt who reflected upon the expression in question, that it was fallacious till this was done. When I first began to write “Life and Habit” I did not believe it could be done, but when I had gone right up to the end, as it were, of my _cu de sac_, I saw the path which led straight to the point I had despaired of reaching—I mean I saw that personality could not be broken as between generations, without also breaking it between the years, days, and moments of a man’s life. What differentiates “Life and Habit” from the “Principles of Psychology” is the prominence given to continued personal identity, and hence to _bonâ fide_ memory, as between successive generations; but surely this makes the two books differ widely. Ideas can be changed to almost any extent in almost any direction, if the change is brought about gradually and in accordance with the rules of all development. As in music we may take almost any possible discord with pleasing effect if we have prepared and resolved it rightly, so our ideas will outlive and outgrow almost any modification which is approached and quitted in such a way as to fuse the old and new harmoniously. Words are to ideas what the fairy invisible cloak was to the prince who wore it—only that the prince was seen till he put on the cloak, whereas ideas are unseen until they don the robe of words which reveals them to us; the words, however, and the ideas, should be such as fit each other and stick to one another in our minds as soon as they are brought together, or the ideas will fly off, and leave the words void of that spirit by the aid of which alone they can become transmuted into physical action and shape material things with their own impress. Whether a discord is too violent or no, depends on what we have been accustomed to, and on how widely the new differs from the old, but in no case can we fuse and assimilate more than a very little new at a time without exhausting our tempering power—and hence presently our temper.