mand his body and
his manifold relative functions, but also the complex range of his
psychical acts. This fact, which as I believe has not been observed
before, is of great importance. It is manifest that the difference
between man and other animals does not consist in the diversity or
discrepancy of the elements of the intelligence, but in its reflex
action on itself; an action which certainly has its conditions fixed by
the organic and physiological composition of the brain.

If it should be said that the traditional opinion of science, as well as
the general sentence of mankind, have always regarded reflection as the
basis of the difference between animals and man, so that there is no
novelty in our principle, the assertion is erroneous. Reflection, as an
inward psychical fact, has certainly been observed by psychologists and
philosophers in all civilized times, and instinctively by every one; nor
could it be otherwise, since reflection is one of the facts most evident
to human consciousness. But although the fact, or the intrinsic and
characteristic action of human thought has been observed, and has often
been discussed and analyzed in some of its elements, yet its genesis has
not been declared, nor has its ultimate cause been discovered. We
propose to discover this ultimate cause, and we refer it to the exercise
of the will over all the elements and acts which constitute human
intelligence; an intelligence only differing from that of animals by
this inward and deliberate fact, which enables man to consider and
examine all his acts, thus logically doubling their range. This
intelligence has in animals a simple and direct influence on their
bodies and on the external world, in proportion to their diverse forms
and inherited instincts; while in man, owing to his commanding attitude,
it falls back upon itself, and gives rise to the inquiring and
reflective habit of science.

We do not, therefore, divide man from other animals, but rather assert
that many proofs and subtle analyses show the identity of their
intelligence in its fundamental elements, while the difference is only
the result of a reaction of the same intelligence on itself. Such a
theory does not in any way interrupt the natural evolution and genesis
of the animal kingdom, while the distinctive peculiarity of man is shown
in an act which, as I believe, clearly explains the new faculty of
reason acquired by him.

I must admit that in speaking of the psyc