anime 101: equivalent exchange

According to Wikipedia, the general principle of equivalent exchange in Fullmetal Alchemist ("To obtain, something of equal value must be lost. That is alchemy's first law of equivalent exchange") was initially inspired by the author's parents, who had to give all their effort working on their farm in order to earn the money to eat.

But the idea of equivalent exchange itself has been around for ages; and not just in relation to alchemy, either. For example, the concept can be found (perhaps most famously) in Aristotle's Nicomachean Ethics, where, in the midst of discussing the role of money in the exchange of commodities, he writes, "If there were no exchange there would be no association, and there can be no exchange without equality, and no equality without commensurability" (1133b.1).

The more you know.