What is Gresham’s Law?

Gresham’s Law is usually phrased as “bad money drives out good,” i.e., money of lesser intrinsic value drives out money of greater intrinsic value.

But maybe the adjectives “bad” and “good" are unfair. The “bad” money, because it doesn’t have some other use like being melted down and made into jewelry, has a comparative advantage at being money, a symbolic medium of exchange. The “good” money, like an American sneaker factory, is at a comparative disadvantage, which is why it is driven out.