Where is the precise line of distinction between man and the animals whom he calls brutes? In what does he differ essentially from beasts? It is, we are told, by his intelligence, by the faculties of his mind, and by his reason, that man appears superior to all other animals, who, in all their actions, move only by physical impulses, in which reason has no share. But finally, brutes, having fewer wants than man, easily do without his intellectual faculties, which would be perfectly useless in their mode of existence. Their instinct is sufficient; while all the faculties of man scarcely suffice to render his existence supportable, and to satisfy the wants, which his imagination and his prejudices multiply to his torment. Brutes are not influenced by the same objects, as man; they have not the same wants, desires, nor fancies; and they very soon arrive to maturity, while the mind of man seldom attains to the full enjoyment and free exercise of its faculties and to such a use of them, as is conducive to his happiness. 96. We are assured, that the human soul is a simple substance. It should then be the same in every individual, each having the same intellectual faculties; yet this is not the case. Men differ as much in the qualities of the mind, as in the features of the face. There are human 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 is there between the genius of a Locke or a Newton, and that of a peasant, Hottentot, or Laplander? Man differs from other animals only in his organization, which enables him to produce effects, of which animals are not capable. The variety, observable in the organs of individuals of the human species suffices to explain the differences in what is called their intellectual faculties. More or less delicacy in these organs, warmth in the blood, mobility in the fluids, flexibility or stiffness in the fibres and nerves, must necessarily produce the infinite diversity, which we observe in the minds of men. It is by exercise, habit and education, that the mind is unfolded and becomes superior to that of others. Man, without culture and experience, is as void of reason and industry, as the brute. A stupid man is one, whose organs move with difficulty, whose brain does not easily vibrate, whose blood circulates slowly. A man of genius is he, whose organs are flexible, whose sensations are quick, whose brain vibrates with celerity. A learned man is he, whose organs and brain have been long exercised upon objects to which he is devoted.