Tamar Gendler, professor of philosophy and psychology at Yale, works through two classic game theory problems in this lecture from Philosophy and the Science of Human Nature. She lays out the Prisoner's Dilemma, where rational individual choices produce a worse outcome for both parties than mutual cooperation would, then runs a live classroom version of the dilemma before turning to the Problem of the Commons, where individually sensible resource use leads to collective depletion. The lecture closes with a survey of strategies people and institutions actually use to escape both traps, from repeated interaction and reputation effects to enforced rules. Recorded at Yale in spring 2011, the talk moves from abstract payoff matrices to concrete classroom demonstration and back, showing why cooperation is structurally hard to sustain even among rational, self-interested actors.