The basic nature of money has gone through tremendous changes and our entire banking system is based almost completely on debt, and NOT on assets.
Tthe goldsmith who made gold that served as the currency for the population, he went on to issue paper certificates that represented the money stored in his vault, and over time what we know as a bank came into existence.
Privately issued bank credit is legally convertible to govennment issued funds. In other words, banks can literally create money without having actual money to back it up. Money is created as debt.
With no debt, there is no money. The whole system is dependent on debt. It is a fallacy to think that if all debts were paid, we would be better off. This is not true. We are dependent on debt. Individuals, corporations and government are all in debt to banks.
Many argue the system itself needs to be replaced, because there is going to be a limit to possible debt, and that we need a more solid basis for out money system.