centaur is composed of man
and horse, or a mermaid of woman and fish. Imagination is like
reasoning in being a mental reaction; but it differs from reasoning in
being manipulation rather than exploration; reasoning consists in
seeing relationships that exist between facts, and imagination in
putting facts into new relationships. These are but rough distinctions
and definitions; we shall try to do a little better after we have
examined a variety of imaginative performances.

"Imagination" and "invention" mean very much the same mental process,
though "imagination" looks rather to the mental process itself, and
"invention" more to the outcome of the process, which is a product
having some degree of novelty and originality.

Imagination, like association and like attention, is sometimes free,
and sometimes controlled. Controlled imagination is directed towards
the accomplishment of some desired result, while free imagination
wanders this way and that, with no fixed aim. Controlled imagination
is seen in planning and designing; free imagination occurs in moments
of relaxation, and may be called "play of the imagination". The free
variety, as the simpler, will be considered first.

Our study will have more point if we first remind ourselves what are
the psychological _problems to be attacked_ in studying any mental
activity. What is the _stimulus_ and what the _response?_ These are
the fundamental questions. But the study of response breaks up into
three subordinate questions, regarding the _tendency_ that is
awakened, regarding the {485} _end-result_ obtained, and regarding the
often complex _process_ or series of responses, that leads to the
end-result.

The response in imagination we have already defined, in a general way,
as mental manipulation, and the end-result as the placing of facts
into new combinations or relationships. The stimulus consists of the
facts, either perceived at the moment or recalled from past
perception, that are now freshly related or combined. The more precise
question regarding the stimulus is, then, as to what sort of facts
make us respond in an inventive or imaginative way; and the more
precise question regarding the end-result is as to what kind of
combinations or new relationships are given to the facts--both pretty
difficult questions. In regard to process, the great question is as to
how any one can possibly escape from the beaten track of instinct and
habit, and do anything new; an