  An illuminating analogy is Nozick's Drowning Case (Nozick 1969, 449). This is a situation in which P (the occupant of a boat) offers to save Q (who is drowning close to the boat) but only if Q promises to pay P $10,000 within three days of reaching shore. One view of this case is that P coerces Q (into paying) if and only if P has a freestanding duty to save Q without reward. Whether P does in fact have such a duty is not something we need to decide upon here and that will depend upon a wide range of facts about the situation.