Bad money drives out good money.
What is Gresham’s law?
Gresham’s law is the economic equivalent of “keeping the good stuff for yourself.” It describes the inevitable moment when a government tries to pretend two things of unequal value are identical. If you have a crisp, 24-carat gold coin and a grubby, copper-plated knockoff, and the law insists both buy the same loaf of bread, you aren’t an idiot; you’re going to spend the copper and bury the gold in the garden. Before long, the “good” money vanishes into private hoards, leaving the streets filled with nothing but fiscal junk.
The principle was named in 1857 by economist Henry Dunning Macleod, who plucked the name of Sir Thomas Gresham from the history books. Gresham was a financier to the Tudor dynasty who spent much of his career watching the English currency get systematically “debased” (a polite term for the government skimming the silver out of the coins). He warned Queen Elizabeth I that her subjects weren’t being fooled; they were treating the national currency like a game of hot potato, passing off the “bad” money as fast as possible while clinging to anything with actual intrinsic worth.
To see how this ancient habit evolved into modern chaos, George Selgin’s Good Money provides a brilliant look at the era when private mints — not governments — actually managed to keep “good” money in the hands of the people. For a more provocative, red-pill perspective on how modern banking still dances with debasement, G. Edward Griffin’s The Creature from Jekyll Island is the definitive, if controversial, deep dive into the US Federal Reserve. These books suggest that while the coins have changed to paper and pixels, the instinct to hoard value remains undefeated.
Sidebar
Thiers’ law
While Gresham’s law says “bad money drives out good,” there is a tipping point known as Thiers’ law. This happens when a currency becomes so worthless (think hyperinflation) that the public simply goes on strike.
At this stage, the “bad” money doesn’t drive out the good: the “good” money comes back with a vengeance. People stop accepting the government’s paper entirely and start trading in stable foreign currencies or gold. It is the moment when the state’s law is overruled by the market’s common sense; the “bad” money is abandoned because it can no longer even perform the basic task of buying a pint of milk.
Ultimately, Gresham’s Law is a reminder that you cannot legislate trust. When a system tries to fake the value of its “tokens,” the public will unfailingly protect their own wealth by hiding it. It is why you spend your tattered, tape-repaired five-pound notes before the pristine ones, and why, on a global scale, real assets tend to go “dark” the moment the printing presses start running too hot.
