rol is exercised by the set into which one is
thrown by the situation which confronts one. The set puts certain
nerve-tracts into readiness to conduct, or in other words, makes
certain groups of ideas come into mind, and makes one satisfied only if
the right ideas come. As long as ideas come that do not satisfy, the
flow keeps on, taking one direction and then another, in accordance with
the way our ideas have become organized. An idea finally comes that
satisfies. We are then said to have reached a conclusion, to have made
up our mind, to have solved our problem.

But the fact that we are satisfied is no sure sign that the problem is
correctly solved. It means only that our past experiences, available at
the time through association, say that the conclusion is right. Or, in
more scientific terms, that the conclusion is in harmony with our past
experience, as it has been organized and made available through
association. There is not within us a little being, a reasoner, that
sits and watches ideas file by and passes judgment upon them. The real
judge is our nervous system with its organized bonds or connections.

An illustration may make the matter clearer: A boy walking along in the
woods comes to a stream too wide for him to jump across. He wishes to be
on the other side, so here is a situation that must be met, a problem
that must be solved. A flow of ideas is started centering about the
problem. The flow is entirely determined and directed by past experience
and the present situation. The boy pauses, looks about, and sees on the
bank a pole and several large stones. He has walked on poles and on
fences, he therefore sees himself putting the pole across the stream and
walking on it. This may be in actual visual imagery, or it may be in
words. He may merely say, "I will put the pole across and walk on it."
But, before having time to do it, he may recall walking on poles that
turned. He is not then satisfied with the pole idea. The perception of
stones may next become clear in his mind, and if no inhibiting or
hindering idea comes up, the stone idea carries him into action. He
piles the stones into the stream and walks across.

As was mentioned above, the flow of ideas may take different forms. The
imagery may take any form but is usually visual, auditory, motor, or
verbal.

Further discussion of the point that reasoning is determined by past
experience may be necessary. Suppose the teacher ask the class a number
o