ak of opposite ideas? Can we not entertain any ideas
peacefully together in our consciousness? From a logical standpoint,
ideas may contradict each other, but that refers to their meaning. As
mere bits of psychological experience, I may have any ideas together in
my consciousness. I can think summer and winter or day and night or
right and left or black and white or love and hate in one embracing
thought. As mere mental stuff, the one idea does not interfere with the
other. On the other hand, this is evident: I cannot will to turn to the
right and to turn to the left at the same time. There may be a wrangling
between those two impulses, but as soon as my will stands for the one,
the other is really excluded. Any action which I am starting to do thus
crowds out the impulse to the opposed action.

In the sphere of psychological facts, we have here indeed the only
relation between two happenings which necessarily involves an
opposition. We could never understand why one brain cell might not work
together with any other brain cell, but we do understand that nature
must provide for an apparatus by which the impulse to one action makes
the impulse to the opposite action ineffective. There is no action which
has not its definite opposite. The carrying out of any impulse involves
the suppression of the contrary impulse, and the impulse not to do an
action involves the suppression of the impulse to do it. When we spoke
of the relations of mind and brain, we mentioned that such a corelation
of mental centers indeed exists. Physiological experiments have
demonstrated that the activity of those centers which stimulate a
certain action reduce the excitability of those brain parts which awaken
the antagonistic action. As far as the world of actions is concerned,
the mechanism of the process of suggestion thus seems not inaccessible
to a physiological understanding.

Various ideas of movements to be carried out are struggling for control
in the cortex of the brain. That is the normal status which precedes any
decision. The channels of motor discharge are open for both
possibilities; we may turn to the right or to the left. Then the play of
associations begins. A larger and larger circle of ideas surrounds the
idea of the one and of the other goal. Those ideas awaken emotions. On
the one side may call our duty and on the other side our pleasure.
Larger and larger parts of the central content of our consciousness, of
our own personalit