The technology of exchange — from grain tallies in Mesopotamian temples to coined metal in Greek city-states to global digital credit — whose most consequential property is not what it buys but what it does to the relationships, values, and institutions of every civilization that uses it
Money is not a thing. It is a social agreement — a shared fiction that works because enough people believe it simultaneously. A coin is metal. A dollar bill is paper. A number in a bank account is a database entry. What makes any of these money is not the material but the collective agreement to treat it as such. Every civilization that has used money has found that this agreement, once established, tends to reorganize everything it touches: how people relate to each other, what they value, how power accumulates, and what kinds of social arrangements become possible or impossible.