Currency is used for trade between multiple distrusting groups, credit is used for trade within a social group. There was an article recently on HN about the highland tribes of Papua New Guinea [1] and it described how the natives would trade amongst tribes using shells.

You actually see this on a small scale today in the functioning of many small communities, eg. you don't actually exchange currency to pay the host of a party, but you are expected to reciprocate and host sometimes yourself if you want to keep getting invited. There's a surprisingly large amount of these unpaid micro-transactions that happen, eg. my wife has gotten free childcare, free advice, free (used) furniture, free baby clothes, etc, all in the heart of Silicon Valley, because she reciprocates and also gives away her old furniture, baby toys, baby clothes, advice, introductions, childcare, etc. But when we have to pay the contractor for work on our house, we need dollars. When we buy a computer, we need dollars. When we buy all those goods that we give away new, we need dollars. That again reinforces the "credit is for people you know, currency is for people you don't" distinction.

Barter is used when a previous currency system collapses. The currency is no longer guaranteed to be accepted, so people want hard goods that they know they can use. But barter is an unstable equilibrium: as you mentioned, currency is just barter where one particular good becomes so widely accepted that people will take it not because they want it, but because it can be traded for other things that they want. There are reports of the Bosnian War [2] that described how alcohol and ammo quickly became pseudo-currencies because they were universally accepted and could easily be traded for what you actually needed.

Graeber isn't wrong, but as an anthropologist he over-indexes on the within-group interactions. There are lots of documented examples of currency emerging spontaneously from trade between groups where the groups all mutually decided that one type of object had value.

[1] https://news.ycombinator.com/item?id=49708431

[2] https://www.scribd.com/document/664716931/How-I-survived-a-y...

Hmm... do you not have a credit card? I often reflect on how paying with dollars seems so disadvantaged in today's economy. If you plan to pay back on time, why would you ever use dollars?

I'm not sure your in group/out group thing really holds up. I think of your credit/wife examples as not "credit" but something like basic reciprocity, closer to barter.

I think it's just a bit of blurring of terms. In my mind, bullets and ammo are just not currency in the same way a coin is. You can call it a "pseudo-currency" but the pseudo is kind of cheating.

I'm also not sure "There are lots of documented examples of currency emerging spontaneously from trade between groups where the groups all mutually decided that one type of object had value" disproves the point about violence/government. Can't I do the "pseudo" move back at you? What is the mechanism of the "mutual decision"? Would it be unlike the ones that lead to states? It sounds like everyone agrees something has value so we can have a dispute resolution mechanism. The implication being if you don't agree the other choice is violence? What if I say this "spontaneous collective of groups" is a "pseudo-government"?

Where would that leave us?