called.

For inventing there is always required a natural aptitude, sometimes, a
happy chance.

The natural disposition should be accepted as a fact. Why does a man
create? Because he is capable of forming new combinations of ideas.
However naive this answer may be, there is no other. The only thing
possible, is the determination of the conditions necessary and
sufficient for producing novel combinations: this has been done in the
first part of this book, and there is no occasion for going over it
again. But there is another aspect in creative work to be
considered--its psychological _mechanism_, and the form of its
development.

Every normal person creates little or much. He may, in his ignorance,
invent what has been already done a thousand times. Even if this is not
a creation as regards the species, it is none the less such for the
individual. It is wrong to say, as has been said, that an invention "is
a new and important idea." _Novelty_ only is essential--that is the
psychological mark: importance and utility are accessory, merely social
marks. Invention is thus unduly limited when we attribute it to great
inventors only. At this moment, however, we are concerned only with
these, and in them the mechanism of invention is easier to study.

We have already seen how false is the theory that holds that there is
always a sudden stroke of inspiration, followed by a period of rapid or
slow execution. On the contrary, observation reveals many processes
that apparently differ less in the _content_ of invention than according
to individual temperament. I distinguish two general processes of which
the rest are variations. In all creation, great or small, there is a
directing idea, an "ideal"--understanding the word not in its
transcendental sense, but merely as synonymous with end or goal--or more
simply, a problem to solve. The _locus_ of the idea, of the given
problem, is not the same in the two processes. In the one I term
"complete" the ideal is at the beginning: in the "abridged" it is in the
middle. There are also other differences which the following tables will
make more clear:

_First Process_ (_complete_).

1st phase 2nd phase 3d phase
IDEA INVENTION, VERIFICATION,
(commencement) or or
Special incubation DISCOVERY APPLICATION
of more or less (end)
duration

The idea excites attention and tak