 Moreover, if an expectationalist aims to offer a theory that explains promissory obligation without the invocation of a convention or practice of promising (like Scanlon does), then the other standard route to explaining promise trust is blocked. If there is a convention in place that governs promises, and if that convention is such as to inspire confidence in promisees that promisors will keep their promises, then promises can be said to generate the necessary expectations. But such a view is incompatible with the claim that conventions aren’t necessary to explain promissory obligations. These objections are pressed against Scanlon’s theory by N. Kolodny and R. J. Wallace (2003).