It is uncontroversial that betrayal of trust which one has encouraged is a grave moral wrong. One case of this is promise breaking, whose self-evident moral wrongness contractarians must invoke to reduce the whole or the most important part of morality to the keeping of a hypothetical mutual agreement for minimal reciprocal services. Mutual advantage, and the sacredness of commitments or encouraged trust, both lie at the heart of what most moral philosophers take to be the point and content of morality.