We are assured that the human soul is a simple substance; but if the
soul is such a simple substance, it ought to be the same in all the
individuals of the human race, who all ought to have the same
intellectual faculties; however, this is not the case; men differ as
much in qualities of mind as in the features of the face. There are in
the human race, beings as different from one another as man is from a
horse or a dog. What conformity or resemblance do we find between some
men? What an infinite distance between the genius of a Locke, of a
Newton, and that of a peasant, of a Hottentot, or of a Laplander!
Man differs from other animals but by the difference of his
organization, which causes him to produce effects of which they are not
capable. The variety which we notice in the organs of individuals of the
human race, suffices to explain to us the difference which is often
found between them in regard to the intellectual faculties. More or less
of delicacy in these organs, of heat in the blood, of promptitude in the
fluids, more or less of suppleness or of rigidity in the fibers and the
nerves, must necessarily produce the infinite diversities which are
noticeable in the minds of men. It is by exercise, by habitude, by
education, that the human mind is developed and succeeds in rising above
the beings which surround it; man, without culture and without
experience, is a being as devoid of reason and of industry as the brute.
A stupid individual is a man whose organs are acted upon with
difficulty, whose brain is hard to move, whose blood circulates slowly;
a man of mind is he whose organs are supple, who feels very quickly,
whose brain moves promptly; a learned man is one whose organs and whose
brain have been exercised a long while upon objects which occupy him.
The man without culture, experience, or reason, is he not more
despicable and more abominable than the vilest insects, or the most
ferocious beasts? Is there a more detestable being in nature than a
Tiberius, a Nero, a Caligula? These destroyers of the human race, known
by the name of conquerors, have they better souls than those of bears,
lions, and panthers? Are there more detestable animals in this world
than tyrants?