The prisoner’s dilemma was first devised in the 1950s by Merrill Flood and Melvin Dresher at the RAND Corporation, and later popularized through Albert W. Tucker’s classroom presentation, where he added the vivid story of two suspects under police interrogation. Since then, the dilemma has become the canonical example in discussions of strategic reasoning, rational choice, and cooperation.
The story runs like this: two prisoners are arrested for a crime and separated into different rooms. Each is offered the same deal. If both stay silent, they will each serve a light sentence. If one betrays the other while the partner stays silent, the betrayer goes free while the other receives a heavy sentence. If both betray, they both receive a medium sentence. Each prisoner must choose without knowing what the other will do.
The situation can be summarized in a simple payoff matrix. Suppose “cooperate” means staying silent and “defect” means betraying:
| Prisoner B: Cooperate | Prisoner B: Defect | |
|---|---|---|
| Prisoner A: Cooperate | (–1, –1) | (–10, 0) |
| Prisoner A: Defect | (0, –10) | (–5, –5) |
Here the numbers represent years in prison (lower is better). From the perspective of each prisoner, defection seems the “safe” strategy: it avoids the worst-case scenario of being betrayed while cooperating. And yet, mutual defection leaves both worse off than if they had simply trusted one another.
Game theorists, economists, and other rational choice theorists—often working within the same intellectual framework—have taken this result to illustrate a troubling paradox: two individuals, each acting “rationally,” end up with a worse outcome than if they had acted with solidarity.
But there is no genuine paradox here. The lesson is that the game theorists’ notion of prudence has been distorted. True prudence—understood in the older, classical sense—was never simply about minimizing personal loss at all costs. It was about wise judgment, taking into account the full range of human goods, including the social bonds of trust, friendship, and mutual cooperation.
The prisoner’s dilemma, properly read, does not undermine prudence. It shows instead that the reductionist framework of rational choice theory misses something essential about human life: that an optimal outcome may require risk, and that trust, fellowship, and pro-social commitment are not naïve, but rational in the richest sense of the word.1
Footnote
In the Catholic tradition, prudence (prudentia) is not cowardly self-preservation, but the “charioteer of the virtues” (Aquinas, ST II–II, q.47, a.1). It governs and directs the other cardinal virtues by ordering action toward the true good. Prudence does not calculate merely what is safest for the individual, but what most fully accords with justice, charity, and the common good. To betray one’s fellow for the sake of reducing one’s own penalty would not be “prudence” in this sense, but a vice—false prudence (prudentia carnis). Thus, far from being paradoxical, the prisoner’s dilemma illustrates the bankruptcy of a secularized, utilitarian definition of prudence when set against the richer horizon of classical and Christian moral thought.