As with the environment of place, so with the environment of individuals.  Most friction between individuals is avoidable friction; sometimes, however, friction springs from such deep causes that no skill in the machine can do away with it.  But how is the man whose brain is not in command of his existence to judge whether the unpleasantness can be cured or not, whether it arises in himself or in the other?  He simply cannot judge.  Whereas a man who keeps his brain for use and not for idle amusement will, when he sees that friction persists in spite of his brain, be so clearly impressed by the advisability of separation as the sole cure that he will steel himself to the effort necessary for a separation.  One of the chief advantages of an efficient brain is that an efficient brain is capable of acting with firmness and resolution, partly, of course, because it has been toned up, but more because its operations are not confused by the interference of mere instincts.

Thirdly, there is the environment of one’s general purpose in life, which is, I feel convinced, far more often hopelessly wrong and futile than either the environment of situation or the environment of individuals.  I will be bold enough to say that quite seventy per cent. of ambition is never realised at all, and that ninety-nine per cent. of all realised ambition is fruitless.  In other words, that a gigantic sacrifice of the present to the future is always going on.  And here again the utility of brain-discipline is most strikingly shown.  A man whose first business it is every day to concentrate his mind on the proper performance of that particular day, must necessarily conserve his interest in the present.  It is impossible that his perspective should become so warped that he will devote, say, fifty-five years of his career to problematical preparations for his comfort and his glory during the final ten years.  A man whose brain is his servant, and not his lady-help or his pet dog, will be in receipt of such daily content and satisfaction that he will early ask himself the question:  ’As for this ambition that is eating away my hours, what will it give me that I have not already got?’ Further, the steady development of interest in the hobby (call it!) of common-sense daily living will act as an automatic test of any ambition.  If an ambition survives and flourishes on the top of that daily cultivation of the machine, then the owner of the ambition may be sure that it is a genuine and an invincible ambition, and he may pursue it in full faith; his developed care for the present will prevent him from making his ambition an altar on which the whole of the present is to be offered up.