The brain is a highly quaint¹ organism. Let me say at once, lest I should be cannonaded by physiologists², psychologists, or metaphysicians, that by the 'brain' I mean the faculty³ which reasons and which gives orders to the muscles. I mean exactly what the plain man means by the brain. The brain is the diplomatist which arranges relations between our instinctive⁴ self and the universe, and it fulfils its mission when it provides for the maximum of freedom to the instincts with the minimum of friction⁵. It argues with the instincts. It takes them on one side and points out the unwisdom of certain performances. It catches them by the coat-tails when they are about to make fools of themselves. 'Don't drink all that iced champagne⁶ at a draught,' it says to one instinct; 'we may die of it.' 'Don't catch that rude fellow one in the eye,' it says to another instinct; 'he is more powerful than us.' It is, in fact, a majestic⁷ spectacle of common sense. And yet it has the most extraordinary lapses⁸. It is just like that man—we all know him and consult him—who is a continual fount of excellent, sagacious advice on everything, but who somehow cannot bring his sagacity to bear on his own personal career.  
In the matter of its own special activities the brain is usually undisciplined and unreliable. We never know what it will do next. We give it some work to do, say, as we are walking along the street to the office. Perhaps it has to devise some scheme for making £150 suffice for £200, or perhaps it has to plan out the heads of a very important letter. We meet a pretty woman, and away that undisciplined, sagacious brain runs after her, dropping the scheme or the draft letter, and amusing itself with aspirations⁹ or regrets for half an hour, an hour, sometimes a day. The serious part of our instinctive self feebly remonstrates¹⁰, but without effect. Or it may be that we have suffered a great disappointment, which is definite and hopeless. Will the brain, like a sensible creature, leave that disappointment alone, and instead of living in the past live in the present or the future? Not it! Though it knows perfectly¹¹ well that it is wasting its time and casting a very painful and utterly¹² unnecessary gloom over itself and us, it can so little control its unhealthy morbid¹³ appetite that no expostulations will induce it to behave rationally. Or perhaps, after a confabulation with the soul, it has been decided¹⁴ that when next a certain harmful instinct comes into play the brain shall firmly interfere¹⁵. 'Yes,' says the brain, 'I really will watch that.' But when the moment arrives, is the brain on the spot? The brain has probably forgotten the affair entirely¹⁶, or remembered it too late; or sighs, as the victorious¹⁷ instinct knocks it on the head: 'Well, next time!'
 
All this, and much more that every reader can supply from his own exciting souvenirs, is absurd and ridiculous on the part of the brain. It is a conclusive¹⁸ proof that the brain is out of condition, idle as a nigger, capricious as an actor-manager, and eaten to the core with loose habits. Therefore the brain must be put into training. It is the most important part of the human machine by which the soul expresses and develops itself, and it must learn good habits. And primarily it must be taught obedience¹⁹. Obedience can only be taught by imposing²⁰ one's will, by the sheer force of volition²¹. And the brain must be mastered by will-power. The beginning of wise living lies in the control of the brain by the will; so that the brain may act according to the precepts²² which the brain itself gives. With an obedient disciplined brain a man may live always right up to the standard of his best moments.
 
To teach a child obedience you tell it to do something, and you see that that something is done. The same with the brain. Here is the foundation of an efficient life and the antidote²³ for the tendency to make a fool of oneself. It is marvellously simple. Say to your brain: 'From 9 o'clock to 9.30 this morning you must dwell without ceasing on a particular topic which I will give you.' Now, it doesn't matter what this topic is—the point is to control and invigorate the brain by exercise—but you may just as well give it a useful topic to think over as a futile²⁴ one. You might give it this: 'My brain is my servant. I am not the play-thing of my brain.' Let it concentrate on these statements for thirty minutes. 'What?' you cry. 'Is this the way to an efficient life? Why, there's nothing in it!' Simple as it may appear, this is the way, and it is the only way. As for there being nothing in it, try it. I guarantee that you will fail to keep your brain concentrated on the given idea for thirty seconds—let alone thirty minutes. You will find your brain conducting itself in a manner which would be comic were it not tragic²⁵. Your first experiments will result in disheartening failure, for to exact from the brain, at will and by will, concentration on a given idea for even so short a period as half an hour is an exceedingly difficult feat—and a fatiguing²⁶! It needs perseverance²⁷. It needs a terrible obstinacy²⁸ on the part of the will. That brain of yours will be hopping²⁹ about all over the place, and every time it hops³⁰ you must bring it back by force to its original position. You must absolutely compel it to ignore every idea except the one which you have selected for its attention. You cannot hope to triumph all at once. But you can hope to triumph. There is no royal road to the control of the brain. There is no patent dodge³¹ about it, and no complicated function which a plain person may not comprehend. It is simply a question of: 'I will, I will, and I will.' (Italics here are indispensable.)
 
Let me resume. Efficient living, living up to one's best standard, getting the last ounce of power out of the machine with the minimum of friction: these things depend on the disciplined and vigorous condition of the brain. The brain can be disciplined by learning the habit of obedience. And it can learn the habit of obedience by the practice of concentration. Disciplinary concentration, though nothing could have the air of being simpler, is the basis of the whole structure. This fact must be grasped imaginatively; it must be seen and felt. The more regularly concentration is practised, the more firmly will the imagination grasp the effects of it, both direct and indirect. After but a few days of honest trying in the exercise which I have indicated, you will perceive its influence. You will grow accustomed to the idea, at first strange in its novelty, of the brain being external to the supreme³² force which is you, and in subjection to that force. You will, as a not very distant possibility, see yourself in possession of the power to switch your brain on and off in a particular subject as you switch electricity on and off in a particular room. The brain will get used to the straight paths of obedience. And—a remarkable³³ phenomenon—it will, by the mere³⁴ practice of obedience, become less forgetful and more effective. It will not so frequently give way to an instinct that takes it by surprise. In a word, it will have received a general tonic³⁵. With a brain that is improving every day you can set about the perfecting of the machine in a scientific manner.