Do moral questions have objective answers? In this great debate, Gilbert Harman explains and argues for relativism, emotivism, and moral scepticism. In his view, moral disagreements are like disagreements about what to pay for a house; there are no correct answers ahead of time, except in relation to one or another moral framework. Independently, Judith Jarvis Thomson examines what she takes to be the case against moral objectivity, and rejects it; she argues that it is possible to find out the correct answers to some moral questions. In her view, some moral disagreements are like disagreements about whether the house has a ghost. Harman and Thomson then reply to each other. This important, lively accessible exchange will be invaluable to all students of moral theory and meta--ethics.