a solution. To take a simple instance, an automobile
may suddenly stop. We know there is a difficulty,
but whether it is a difficulty with the transmission, with the
carburetor, or with the supply of gasoline, we cannot at first
tell. Before we do anything else in solving our problem, we
find out literally and precisely _what the trouble is_. To take a
different situation, a doctor does not undertake to prescribe
for a patient until he has diagnosed the difficulty, found out
precisely what the features of the problem are.

The second step after the situation has been examined and
its precise elements defined, is _suggestion_. That is, we
consider the various possibilities which _suggest_ themselves as
solutions to our problem. There may be several ways of temporarily
repairing our engine; the doctor may think of two or
three possible treatments for a disease. In one sense, suggestion
is uncontrollable. The kind of suggestions that occur to
an individual depend on his "genius or temperament," on his
past experiences, on his hopes or fears or expectations when
that particular situation occurs. We can, however, through
the methods of science, control suggestions indirectly. We
can do this, in the first place, by reexamining the facts which
give rise to suggestion. If upon close examination, the facts
appear differently from what they did at first, we will derive
different inferences from them. Different suggestions will
arise from the facts _A, B, C_, than from the facts _A', B', C'_.
Again we can regulate the conditions under which credence is
given to the various suggestions that arise. These suggestions
are entertained merely as tentative, and are not accepted
until experimentally verified. "The suggested conclusion as
only tentatively entertained constitutes an idea."

After the variety of suggestions that proffer themselves as
solutions to a problem have been considered, the third step is
the logical development of the idea or suggestion that gives
most promise of solving the difficulty. That is, even before
further facts are sought, the idea that gives promise of being a
solution is followed out to its logical consequences. Thus, for
example, astronomers were for a long time puzzled by unexplained
perturbations in the path of the planet Uranus. The
suggestion occurred that an unseen planet was deflecting it
from the path it should, from observation and calculation,
be following. If this were the case, from the a