Contractarianism and contractualism are instances of a major approach to normative ethical theory that stresses reciprocity and mutual consent. 'Contractarianism' is the name given to the idea, first broached by Thomas Hobbes, that morality can be viewed as a set of social practices that self-interestedly rational actors "adopt" in their common interest, as if by a kind of contract. 'Contractualism' refers, on the other hand, to a related, but importantly...