Just how
to conceive this inner work physiologically is as yet impossible, but
psychologically we all know what the word means. We need a particular
spur or effort to start us upon inner work; it tires us to sustain it;
and when long sustained, we know how easily we lapse. When I speak of
"energizing," and its rates and levels and sources, I mean therefore
our inner as well as our outer work.

Let no one think, then, that our problem of individual and national
economy is solely that of the maximum of pounds raisable against
gravity, the maximum of locomotion, or of agitation of any sort, that
human beings can accomplish. That might signify little more than
hurrying and jumping about in inco-ordinated ways; whereas inner work,
though it so often reinforces outer work, quite as often means its
arrest. To relax, to say to ourselves (with the "new thoughters")
"Peace! be still!" is sometimes a great achievement of inner work.
When I speak of human energizing in general, the reader must therefore
understand that sum-total of activities, some outer and some inner,
some muscular, some emotional, some moral, some spiritual, of whose
waxing and waning in himself he is at all times so well aware. How to
keep it at an appreciable maximum? How not to let the level lapse?
That is the great problem. But the work of men and women is of
innumerable kinds, each kind being, as we say, carried on by a
particular faculty; so the great problem splits into two sub-problems,
thus:

(1). What are the limits of human faculty in various directions?

(2). By what diversity of means, in the differing types of human
beings, may the faculties be stimulated to their best results?

Read in one way, these two questions sound both trivial and familiar:
there is a sense in which we have all asked them ever since we were
born. Yet _as a methodical programme of scientific inquiry_, I doubt
whether they have ever been seriously taken up. If answered fully;
almost the whole of mental science and of the science of conduct would
find a place under them. I propose, in what follows, to press them on
the reader's attention in an informal way.

The first point to agree upon in this enterprise is that _as a rule men
habitually use only a small part of the powers which they actually
possess and which they might use under appropriate conditions_.

Every one is familiar with the phenomenon of feeling more or less alive
on different days. Every one kn