At any given moment, what money is just seems like the natural state of the world, right? Most people, most of the time, don't really think about it. They just think, "Oh, yes, this piece of paper in my wallet, this number in my account, that's what money is. Fine, whatever.

That's just the way the world works." But the lesson, the insight to me that was really interesting, exciting is that's not necessarily the way the world works. It didn't used to work that way. It'll probably be different in the future. And so that's what's fun. Money turns out to be this set of rules, this set of arrangements that a society agrees on without really realizing that they're agreeing on something quite often.

It is kind of emergent and it's kind of bottom-up more than you might think, rather than let's have a constitutional convention and decide what money is.