you, in a word, ultimately and
essentially _live_ with your brain? No. Your brain is an instrument. The
proof that it is an instrument lies in the fact that, when extreme
necessity urges, _you_ can command your brain to do certain things, and
it does them. The first of the two great principles which underlie the
efficiency of the human machine is this: _The brain is a servant,
exterior to the central force of the Ego_. If it is out of control the
reason is not that it is uncontrollable, but merely that its discipline
has been neglected. The brain can be trained, as the hand and eye can be
trained; it can be made as obedient as a sporting dog, and by similar
methods. In the meantime the indispensable preparation for brain
discipline is to form the habit of regarding one's brain as an
instrument exterior to one's self, like a tongue or a foot.

IV

THE FIRST PRACTICAL STEP

The brain is a highly quaint organism. Let me say at once, lest I should
be cannonaded by physiologists, psychologists, or metaphysicians, that
by the 'brain' I mean the faculty 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
instinctive self and the universe, and it fulfils its mission when it
provides for the maximum of freedom to the instincts with the minimum of
friction. 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 champagne 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 majestic spectacle of common sense. And yet it has the most
extraordinary lapses. 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 L150 suffice for
L200, or perhaps it has to plan out the heads of a very important
letter. We