The trolley problem is a series of thought experiments in ethics and psychology, involving stylized ethical dilemmas of whether to sacrifice one person to save a larger number. Opinions on the ethics of each scenario turn out to be sensitive to details of the story that may seem immaterial to the abstract dilemma. The question of formulating a general principle that can account for the differing moral intuitions in the different variants of the story was dubbed the "trolley problem" in a 1976 philosophy paper by Judith Jarvis Thomson.
