life which he wanted. All must have had the same duties to perform, and the
same work to do, and there could have been no such difference of employment
as could alone give occasion to any great difference of talents.

As it is this disposition which forms that difference of talents, so
remarkable among men of different professions, so it is this same
disposition which renders that difference useful. Many tribes of animals,
acknowledged to be all of the same species, derive from nature a much more
remarkable distinction of genius, than what, antecedent to custom and
education, appears to take place among men. By nature a philosopher is not
in genius and disposition half so different from a street porter, as a
mastiff is from a grey-hound, or a grey-hound from a spaniel, or this last
from a shepherd's dog. Those different tribes of animals, however, though
all of the same species are of scarce any use to one another. The strength
of the mastiff is not in the least supported either by the swiftness of the
greyhound, or by the sagacity of the spaniel, or by the docility of the
shepherd's dog. The effects of those different geniuses and talents, for
want of the power or disposition to barter and exchange, cannot be brought
into a common stock, and do not in the least contribute to the better
accommodation and conveniency of the species. Each animal is still obliged
to support and defend itself, separately and independently, and derives no
sort of advantage from that variety of talents with which nature has
distinguished its fellows. Among men, on the contrary, the most dissimilar
geniuses are of use to one another ; the different produces of their
respective talents, by the general disposition to truck, barter, and
exchange, being brought, as it were, into a common stock, where every man
may purchase whatever part of the produce of other men's talents he has
occasion for,