Is money the root of all evil, or is it just a technology that makes our lives more efficient? Should some things not be for sale? This week on Philosophy Talk, we’ll be discussing money: where it comes from, what it is now, and what it could become in the future.

You might think that something counts as money just in case it’s a valuable commodity that everybody is willing to barter for. Some forms of money, like gold coins, certainly fit this description. Others, like deeds that entitle the bearer to gold, are valuable because they represent valuable commodities. But it’s common for money to be backed not by a valuable commodity, but by fiat—that is, a declaration by a central bank which says that it’s valuable.

According to another view, known as neo-chartalism, it’s the central bank, together with an authority that levies taxes, that makes something count as money. This view entails that some things that appear to be money—like Bitcoin, or Somali shillings—don’t really count.

Personally, I think money can take many forms, so long as it serves as a shared medium that makes barter more efficient. But even setting aside the metaphysical worries I’ve raised about money, you might be vexed by ethical concerns. Putting monetary prices on things makes it easy to compare their values: the San Francisco SPCA charges $175 to adopt an adult dog, while a Nintendo Switch costs $299. But does it really make sense to say that a dog is worth less than a Nintendo Switch? Putting a price on a dog might invite inappropriate comparisons. (Such comparisons can, however, be used to great rhetorical effect: see Neil Sinhababu’s ways of reckoning the cost of the Iraq War on his blog War or Car?)

Perhaps some things just shouldn’t be bought and sold. I think the government should provide basic goods and services, such as roads, schools, public transit, and health care, rather than allowing these things to be traded in markets. And many people find it unsavory to sell babies, or kidneys, even though they approve of adoption and kidney donation.

So perhaps, contrary to popular wisdom, money is something you can have too much of after a while. I’m looking forward to puzzling over these questions with our guest, Graham Hubbs, on this week’s upcoming show, Money Matters.