A Rule of One.

The article explains the principle, a rule of one. This means that one rational person is enough to make a market and that one irrational person is enough to break a game. The power of the market as an exchange institution rests in its ability to move resources from low- to high-valued uses. If one person is rational enough to look for arbitrage opportunities among the other irrational players, the market works. In contrast, it suffices for one person to behave irrationally for a game to yield outcomes that deviate from the predicted actions of rational behavior.