Two people would both prefer mutual cooperation to mutual defection. Yet each can see a reason to defect, whatever the other chooses. That tension, rather than the presence of an actual prison, is what makes the prisoner’s dilemma useful to think with.
The Stanford Encyclopedia of Philosophy’s account explains the ordering of outcomes behind the dilemma. The individual temptation to defect and the shared benefit of cooperation pull in different directions.
Read an illustrative scorecard
Imagine a one-round game in which higher points are better. If both cooperate, each gets three points. If both defect, each gets one. If only one defects, the defector gets five and the cooperator gets zero. These numbers are an illustrative model, not measurements of real people’s preferences.
Consider your choice in two separate cases. If the other player cooperates, defecting gives you five instead of three. If the other defects, defecting gives you one instead of zero. In either case, defection gives the higher individual score. If both follow that reasoning, each gets one, even though mutual cooperation would have given each three.
Check the assumptions before applying the label
For a real disagreement, first ask what each participant actually values. Are the choices simultaneous? Can agreements be enforced? Will they interact again? Does harming the other person carry a cost that your scorecard omitted?
Write down those assumptions before declaring that a workplace dispute or neighbourhood problem is a prisoner’s dilemma. A different ordering of preferences can produce a different game, even when the situation sounds superficially similar.
The model does not prove that selfishness is always wise or that cooperation is naive. It isolates a particular incentive problem. Its practical value is in making the structure visible, so people can ask whether communication, future interaction or a changed arrangement would alter the choices they face.