Ideas are modified and become purer as they converge into types, and the
principle and method at once become more rational. Either in the faculty
of perception and in its elements, or in the inward classification of
specific forms, or again in the more perfect empirical knowledge of
phenomena, the progress of myth and science go on together, and they are
not only developed in a parallel direction, but the form becomes the
covering, involucre, matrix, or, as I might say, the _cotyledons_, by
means of which the latter is developed and nourished. Even in more
rational science this faculty, and these elements, necessarily recur,
since in every human conception we find the material aspect, or its
mental image, the thing and its cause, and, as we shall see, some
mythical personality is insensibly identified with it.

The act which produces myth is therefore the same from which science
proceeds, so that their original source is identical. The same process
which constitutes the fetish and myth also constitutes science in its
conditions and form, and here we find the unique fact which generates
them both; science, like myth, would be impossible without apprehension,
without the individuation of ideas, and the classification and
specification of types.

Before going further I must briefly recapitulate the order of ideas and
facts which we have observed, so that the process may be as strictly
logical as it is practical. Since, in the elements of apprehension,
perception is absolutely identical in man and animals, its primitive
effects in animating natural phenomena are the same. But man, by means
of his reduplicative faculty, retains a mental image of the personified
subject which is only transitory in the case of animals, and it thus
becomes an inward fetish, by the same law, and consisting of the same
elements as that which is only extrinsic. These phantasms are, moreover,