Examples abound throughout history of this beneficial borrowing of ideas and the ways in which trade has facilitated it. Ideas know no borders. They have never known borders. Archaeologists and historians tell us that extensive trade routes can be traced at least as far back as 8500 BC, when much-sought obsidian—a hard volcanic glass used to produce a chipped stone blade—was exported overland hundreds of miles from what is today central and western Turkey to what is today southwestern Iran and Jordan. They also tell us that seafaring trade dates from at least 7000 BC, when coastal people from the Argolid region in the Greek Peloponnese used island hopping to import obsidian from the island of Melos about 100 miles away. In 1966, the 20th-century British classicist A. R. Burn remarked in his book The Pelican History of Greece that “in its time, it was like putting a man on the moon.”
For millennia, ideas have covered long distances and crossed borders with trade. Sometimes the ideas are contained in the traded goods themselves—such as with a new way to make stone blades. And sometimes the ideas are in the minds of the people who have traveled with the traded goods, starting with the ancient trade caravans, which were not infrequently accompanied by “large numbers of people, including traders, caravan leaders, sailors and the like” and thinkers who hoped to spread their ideas, search for new ideas, or both. Ideas also have traveled with migration and with the imperial expansion of military conquest. Yet, on a day-to-day basis, the travel of ideas has been a common consequence of the more mundane commerce of trade.
As one example of the travel of ideas, in his book The Shape of Ancient Thought, the late American thinker and scholar Thomas McEvilley argued that the modern Western world must be considered a combined product of both Greek and Indian thought because of the ways in which trade and other exchanges created a mixing of ideas throughout the Mediterranean, the Middle East, and South Asia in antiquity. The late British classicist Richard Seaford maintained much the same, saying that the ideas of the Greek philosophers were influenced by those of the Indian philosophers, and, in turn, the ideas of the Indians were influenced by those of their Greek counterparts.
Trade routes, both land and sea, were also routes for new ideas that became religions. Buddhism spread along the Silk Road from India to Central Asia, China, and Northeast Asia. Later, in turn, Buddhist monks from China used the same trade routes to travel to India to find and study Buddhist scriptural texts. Similarly, the Christian apostle Paul traveled in trading vessels on his missionary journeys in the Mediterranean and contributed greatly to the early spread of the idea of Christianity. Humanity has benefited enormously from the dissemination of these and other consoling and animating forms of belief.
As still another illustration, the 20th-century Austrian and British philosopher Sir Karl Popper, in his 1945 book The Open Society and Its Enemies, traced the origin of the ancient Athenians’ “democratic tendencies” in part to their embrace of trade. Trade helps end the intellectual and other forms of isolation that keep societies such as the one in pre-democratic Athens closed. Popper said, “Perhaps the most powerful cause of the breakdown of the closed society was the development of sea-communications and commerce,” in which the Athenians were among the leaders in the ancient Aegean world. Commerce “was perhaps the worst danger to the closed society.” Then and now, trade can help pry a closed society open.
“By the sixth century B.C.,” Popper explained, the development of seafaring commerce in Greece “had led to the partial dissolution of the old ways of life, and even to a series of political revolutions and reactions. And it had led not only to attempts to retain and to arrest tribalism by force, as in Sparta, but also to that spiritual revolution, the invention of critical discussion.” As much as he emphasized the benefits of rational dialogue in his accounts of the inquiries of his mentor Socrates, this was in no small part what the Athenian philosopher Plato, with his aristocratic disdain for the bausanic commercial world, feared about the consequences of the increase of trade, foreign and otherwise.
As expressed in the dictatorial structure of his imagined Republic and in his conception of the utopian city of Magnesia in his later and longest dialogue, the Laws, part and parcel with Plato’s criticism of democracy was his criticism of commerce and of the new ideas that were furthered by trade. “To have the sea nearby,” he wrote in the Laws, may be pleasant, but “it fills the land with wholesaling and retailing, breeds shifty and deceitful habits in a man’s soul, and makes the citizens distrustful and hostile, not only among themselves, but also in their dealings with the world outside.” It also contributed to producing the individual freedom of action that Plato adamantly opposed.
Facilitated by trade, the invention of critical discussion in Athens led, a century before Plato, to the conception of the new idea that became democracy. As the British classicist Peter Green wrote in The Greco-Persian Wars, what the feudalistic Persians despised most about the Greeks, as exemplified by the Athenians, was their “addiction to trade,” and especially, “the free exchange of opinions that went with it.” The same might be said of how trade has, in the 2,500 years since and in so many places throughout the world, promoted more openness to uncounted new ways of thinking and doing and living. In particular, this can be said about the idea of democracy.
After democracy was rediscovered several centuries ago at the outset of the modern era, in the years that followed, as historian Mark Mazower recounted in Governing the World: The History of an Idea, 1815 to the Present, “The spread of democracy and trade went hand in hand.” Especially in the second half of the 20th century, even amid the Cold War between the United States and the Soviet Union, and especially in the final decade of the century, following the Soviet collapse in 1991, the advance of trade was accompanied by the advance of democracy. It is only now that the prospects for democracy appear to many to be abating. It is no coincidence that this is occurring when the growth of trade is slowing amid a global backlash of protectionism led by an increasingly insular United States.
The “civilizing virtues of commerce” have long been thought to have a tempering effect on the worst tendencies among us. Trade has long been portrayed as a harbinger of peace. The idea of free trade itself, which has traveled alongside the increasing exchange of goods and services it creates, has long been linked—in David Ricardo’s words—with the hoped-for creation of a “universal society of nations in the civilized world.” Overall, the evidence suggests that trade does promote peace. Even so, the highest of the hopes of those who have sought free trade have yet to be realized. Nowadays, it sometimes seems that trade leads to conflict almost as much as it leads to comity. Witness the ongoing “trade war” between the United States and China. Still, the hopes remain.