with the best of scientific consciences, knowing that
the predetermination of the amount of my effort of attention can never
receive objective proof, and hoping that, whether you follow my example
in this respect or not, it will at least make you see that such
psychological and psychophysical theories as I hold do not necessarily
force a man to become a fatalist or a materialist.

Let me say one more final word now about the will, and therewith
conclude both that important subject and these lectures.

There are two types of will. There are also two types of inhibition. We
may call them inhibition by repression or by negation, and inhibition by
substitution, respectively. The difference between them is that, in the
case of inhibition by repression, both the inhibited idea and the
inhibiting idea, the impulsive idea and the idea that negates it, remain
along with each other in consciousness, producing a certain inward
strain or tension there: whereas, in inhibition by substitution, the
inhibiting idea supersedes altogether the idea which it inhibits, and
the latter quickly vanishes from the field.

For instance, your pupils are wandering in mind, are listening to a
sound outside the window, which presently grows interesting enough to
claim all their attention. You can call the latter back again by
bellowing at them not to listen to those sounds, but to keep their minds
on their books or on what you are saying. And, by thus keeping them
conscious that your eye is sternly on them, you may produce a good
effect. But it will be a wasteful effect and an inferior effect; for the
moment you relax your supervision the attractive disturbance, always
there soliciting their curiosity, will overpower them, and they will be
just as they were before: whereas, if, without saying anything about the
street disturbances, you open a counter-attraction by starting some very
interesting talk or demonstration yourself, they will altogether forget
the distracting incident, and without any effort follow you along.
There are many interests that can never be inhibited by the way of
negation. To a man in love, for example, it is literally impossible, by
any effort of will, to annul his passion. But let 'some new planet swim
into his ken,' and the former idol will immediately cease to engross his
mind.

It is clear that in general we ought, whenever we can, to employ the
method of inhibition by substitution. He whose life is based upon the
word