This essay argues that the concept of ‘reasonableness’plays an important role in Scanlon's, Rawls's, and Barry's theories of justice (or morality). The relationship between moral motivation and reasonableness is critically analysed. Specifically, the paper questions whether it is plausible to impute to the agents of construction the desire ‘to justify our actions to others on impartial terms’. It also argues that most of the work is done by the assumption that people are reasonable rather than by the contractarian formulation. Indeed, (...) the paper argues, the argument could proceed entirely by making explicit and arguing for the moral assumptions embedded in the concept of reasonableness [1]. (shrink)