> 'Money' is just IOU notes. So then the various cryptocurrencies fit the bill because a lot of people are willing to treat them as IOU notes among themselves.

> 'Money' is just IOU notes. So then the various cryptocurrencies fit the bill because a lot of people are willing to treat them as IOU notes among themselves. > What gives these IOU notes value is that governments use them for paying welfare and civil servant salaries, and in turn take them back when collecting taxes. But if some people are willing to treat a cryptocurrency as IOU notes, then that cryptocurrency is exchangeable for a currency like USD, EUR, etc, again allowing me to pay those taxes. This is no different than the case of me using USD to produce money for paying taxes to my own country which doesn't acknowledge USD, which you haven't addressed. > Yes. But with a caveat: the wealth of a government's welfare/civil servant class and the threat of its tax collectors is what gives currency value. I disagree. I agree with your initial point, though: money is just IOU notes. As long as there is someone willing to buy those IOU notes off of you, it's valuable.