Economic historian Karl Polanyi has argued that where barter is widespread, and cash supplies limited, barter is aided by the use of credit, brokerage, and money as a unit of account (i.e. used to price items). All of these strategies are found in ancient economies including Ptolemaic Egypt. They are also the basis for more recent barter exchange systems.[15]
But the harm may go deeper than a mistaken view of human psychology. According to Graeber, once one assigns specific values to objects, as one does in a money-based economy, it becomes all too easy to assign value to people, perhaps not creating but at least enabling institutions such as slavery (in which people can be bought) and imperialism (which is made possible by a system that can feed and pay soldiers fighting far from their homes). 

In 2012, the average Canadian had more than $27,000 in consumer debt. Wages are shrinking, costs are rising, and one-third of us are living paycheque to paycheque. “Most of us live beyond our means both financially and ecologically,” says Marta Nowinska, founder and president of one of Canada’s largest bartering communities, Swapsity, which launched in 2010. “Swapping is a viable approach to solving a lot of real problems,” she says. Like Simmons, Nowinska left a Bay Street job to join the world of barter. The idea for Swapsity came to her one day in 2006: she was on the subway and noticed how miserable everybody looked. She started to think about a business that could empower people. At first, she thought people could swap jobs, but dismissed it as unrealistic. Then: what if they could swap other things? She developed a business plan and launched a website.
It helped that she had something other people wanted. “If I had gone in and offered to bake a pie for a free night at their hotel,’ they’d probably have said ‘no.’ ” One Barter Babe, Carly Boyce, knitted Simmons an exact replica of a favourite hat Simmons had lost but luckily had a picture of herself wearing. When it came time for the trade, Boyce remembers feeling guilty because the hat was so easy for her to make, and she told Simmons so. Simmons laughed: it was incredibly easy, she told Boyce, for her to give financial advice. It was a funny conversation, Boyce says, but also one that gets at the essence of bartering: when money is taken out of the equation, value is a moving, customizable concept—and that’s just the way most barterers like it.

The man who arguably founded modern economic theory, the 18th-century Scottish philosopher Adam Smith, popularized the idea that barter was a precursor to money. In The Wealth of Nations, he describes an imaginary scenario in which a baker living before the invention of money wanted a butcher’s meat but had nothing the butcher wanted.“No exchange can, in this case, be made between them,” Smith wrote.
Trade did occur in non-monetary societies, but not among fellow villagers. Instead, it was used almost exclusively with strangers, or even enemies, where it was often accompanied by complex rituals involving trade, dance, feasting, mock fighting, or sex—and sometimes all of them intertwined. Take the indigenous Gunwinggu people of Australia, as observed by the anthropologist Ronald Berndt in the 1940s:
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For one thing, the barter myth “makes it possible to imagine a world that is nothing more than a series of cold-blooded calculations,” writes Graeber in Debt. This view is quite common now, even when behavioral economists have made a convincing case that humans are much more complicated—and less rational—than classical economic models would suggest.
This sort of scenario was so undesirable that societies must have created money to facilitate trade, argues Smith. Aristotle had similar ideas, and they’re by now a fixture in just about every introductory economics textbook. “In simple, early economies, people engaged in barter,” reads one. (“The American Indian with a pony to dispose of had to wait until he met another Indian who wanted a pony and at the same time was able and willing to give for it a blanket or other commodity that he himself desired,” read an earlier one.)

When barter has appeared, it wasn’t as part of a purely barter economy, and money didn’t emerge from it—rather, it emerged from money. After Rome fell, for instance, Europeans used barter as a substitute for the Roman currency people had gotten used to. “In most of the cases we know about, [barter] takes place between people who are familiar with the use of money, but for one reason or another, don’t have a lot of it around,” explains David Graeber, an anthropology professor at the London School of Economics.

In Spain (particularly the Catalonia region) there is a growing number of exchange markets.[24] These barter markets or swap meets work without money. Participants bring things they do not need and exchange them for the unwanted goods of another participant. Swapping among three parties often helps satisfy tastes when trying to get around the rule that money is not allowed.[25]