A runaway trolley is heading toward five people. You can divert it onto another track, where one person stands. Do you turn the switch?
Now change one detail. The only way to stop the trolley is to push a bystander in front of it. In both versions, one person dies and five are saved. Yet many people judge turning the switch differently from pushing the stranger. What changed: the numbers, or the way the harm enters the plan?
One explanation appeals to intention: in the switch case, harm to the one may be a foreseen side effect; in the push case, the person is used as the means of stopping the trolley. That distinction is influential, but it does not settle either verdict. Philosophers debate whether the cases really differ morally, and whether a tidy thought experiment can guide choices outside its invented tracks.