Gresham’s Law teaches us that when two forms of value coexist, the one perceived as "worse" often dominates—because people hoard the better one. It’s not just about money; it’s a law of systems, incentives, and integrity that echoes through attention economies, data quality, AI signals, and human trust.
“Bad money drives out good.” That’s the classic summary of Gresham’s Law, first articulated in the 16th century. It refers to a scenario where undervalued “good” currency is removed from circulation while overvalued or debased “bad” currency floods the system.
But zoom out: this isn’t just about coins.
Any system where value signals are distorted is vulnerable to Gresham’s Law.
Attention platforms, social media, content quality, even training data in AI systems—when bad inputs are easier, cheaper, or incentivized, the good ones disappear. This law warns us: value decay is self-reinforcing unless actively countered.
Let’s unpack the mechanics:
It’s a principle of substitution under asymmetric valuation. When two forms of something (currency, content, reputation) are treated as equal in official terms—but not equal in perceived value—people will:
Outcome: the system gets flooded with low-quality input.
Gresham’s Law is entropy applied to value.
Humans naturally act to protect their highest perceived-value assets—this is why we hoard gold during inflation, avoid genuine vulnerability on social media, or under-share good ideas in low-trust environments. System design often ignores this instinct—and gets diluted.
Models don’t know good from bad unless you define and reward it. If you flood a model with cheap or gamed data, it will optimize for the wrong signal. Gresham’s Law is what happens when quantity overwhelms quality in training loops.
To beat Gresham’s Law, you must protect the higher-quality input. That requires friction, filtering, and intelligent incentives.
Gresham’s Law is a system telling you: you need better filters and stronger standards.
If you don’t actively protect value, the system will default to noise—because Gresham always wins unattended.