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.