… is from Book I, Chapter 2 – on pages 29-30, Vol. 1, of the 1981 Liberty Fund edition – of Adam Smith’s 1776 An Inquiry Into the Nature and Causes of the Wealth of Nations (emphasis added):
But without the disposition to truck, barter, and exchange, every man must have procured to himself every necessary and conveniency of 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 greyhound, or a greyhound 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.
DBx: Specialization and trade unite us – they are the foundation of society that extends beyond the family. Trade is the root of civilization.
And also, as Smith notes, specialization and trade allow us peacefully to share in the fruits of other’s people’s talents, creativity, labor, and unique circumstances – and other people to share in the fruits of ours. Those who restrict trade by whatever means restrict the reach of civilization. They restrict the ability of members of their group, however defined, to share in the fruits of non-group-members’ talents, creativity, labor, and unique circumstances. Whether motivated by greed, ignorance, or both, trade restrictions reduced the size of what Smith called the “common stock” of human prosperity.
Trade enriches. Trade restrictions impoverish.