progress. Our theory, besides giving a rational explanation
of the different forms assumed by thought in the course of its historic
evolution, will, I hope, also account for many psychological phenomena
which have hitherto been imperfectly understood, such as dreams,
hallucinations, the aberrations of insanity, and the like. The primitive
fact and its effects reappear in these conditions, and this influence is
persistent and enters into all our acts, conscious or unconscious,
voluntary or involuntary.

It follows from the innate necessity of the perception that objects and
their extrinsic and intrinsic causes are resolved into living subjects,
and are classified in a hierarchy of specific types, which are accepted
by the primitive and ignorant mind as the universal mythical forms.[26]
But the necessities of human speech, which is however involved in
mythical representations, from the very beginning essentially reflex,
require other terms than those of individual and specific animations. It
is clear that the simple personifying faculty of the intellect sufficed
in its earliest emotions, but that after the slow development of
psychical reduplication, and the enlargement of languages and ideas, it
no longer satisfied the logical requirements of the mind.

Consequently, explicit,--that is, rational--singular, and specific ideas
gradually arose and assumed a definite form; they were interwoven and
fused into these individual and specific types, and thus obtained a
place in the thoughts and language of primitive man. The gradual
intrusion of specific rational ideas is natural to the human mind, since
it is logically progressive, and the fact may be observed by those who
watch the mental growth of children, and of ignorant and untaught
adults.

While the mythical intelligence continues as before to give its habitual
mythical interpretation of many natural phenomena, the use is gradually
acquired of special and generic symbols which express special and
specific ideas, and these no longer include a personification of the
individual thing or idea. Without this intrusion of rational ideas any
progress would be impossible, as well as the power of expressing all
which time and education present to the mind, and gradually enable it to
comprehend; the fanciful image is fused in a rational conception, which
is, however, not yet definite and explicit.

What are commonly termed abstract ideas arise from this necessity, as
the result