Promising is clearly a social practice or convention. By uttering the formula, “I hereby promise to do X,” we can raise in others the expectation that we will in fact do X. But this succeeds only because there is a social practice that consists (inter alia) in a disposition on the part of promisers to do what they promise, and an expectation on the part of promisees that promisers will so behave. It is equally clear that, barring special circumstances of (...) some kind, it is morally wrong for promisers to fail to do what they have promised to do. What is perhaps less clear is how the moral wrongness that is involved when promises are broken is related to the social practice that makes promising possible in the first place. (shrink)