they can later be recalled reciprocally,
although the two original occurrences _A_ and _a_ have previously never
existed together, and sometimes, indeed, may not possibly have existed
together. It is evident that the crucial moment is the second, and that
it consists of an act of active assimilation. Thus James maintains that
"it is a relation that the mind perceives after the fact, just as it may
perceive the relations of superiority, of distance, of causality, of
container and content, of substance and accident, or of contrast between
an object, and some second object which the associative machinery calls
up."[9]

Association by resemblance presupposes a joint labor of association and
dissociation--it is an active form. Consequently it is the principal
source of the material of the creative imagination, as the sequel of
this work will sufficiently show.

After this rather long but necessary preface, we come to the
intellectual factor rightly so termed, which we have been little by
little approaching. The essential, fundamental element of the creative
imagination in the intellectual sphere is the capacity of thinking by
analogy; that is, by partial and often accidental resemblance. By
analogy we mean an imperfect kind of resemblance: like is a genus of
which analogue is a species.

Let us examine in some detail the mechanism of this mode of thought in
order that we may understand how analogy is, by its very nature, an
almost inexhaustible instrument of creation.

1. Analogy may be based solely on the _number of attributes compared_.
Let _a b c d e f_ and _r s t u d v_ be two beings or objects, each
letter representing symbolically one of the constitutive attributes. It
is evident that the analogy between the two is very weak, since there is
only one common element, _d_. If the number of the elements common to
both increases, the analogy will grow in the same proportion. But the
agreement represented above is not infrequent among minds unused to a
somewhat severe discipline. A child sees in the moon and stars a mother
surrounded by her daughters. The aborigines of Australia called a book
"mussel," merely because it opens and shuts like the valves of a
shellfish.[10]

2. Analogy may have for its basis the _quality_ or _value_ of the
compound attributes. It rests on a variable element, which oscillates
from the essential to the accidental, from the reality to the
appearance. To the layman, the likeness between ceta