In his book What We Owe to Each Other, Thomas Scanlon proposes what he calls a ‘contractualist’ explanation of what he describes as ‘a central part of the territory called morality’, i.e. our duties to other rational creatures. If Scanlon is right, the fact that another creature is rational generates a particular kind of moral constraint on how we may act towards it: one should ‘treat rational creatures only in ways that would be allowed by principles that they could not reasonably reject insofar as they too were seeking principles of mutual governance which other rational creatures could not reasonably reject. This is then used to explain what makes actions right, at least within his central moral area. Such actions will be right because they are permitted by principles that cannot reasonably be rejected. In this essay, I question both whether Scanlon succeeds in identifying a proper part of the moral terrain as a subject for his account and also what, if any, is the contractualist content of that account. I argue that he equivocates between two distinct and incompatible conceptions of the justifiability of principles. According to the first, justifiability is a relation between principles and people, whilst according to the second, for a principle to be justifiable is for it to be justified. For his explanation of morality to have any contractualist force, justifiability needs to be understood as a relation, but for that explanation to have any plausibility, justifiability must be understood nonrelationally. Because of this, the account is unstable and fails to describe any part of the moral landscape.