 Further, as Lon Fuller and William Perdue pointed out in an influential 1936/37 article “The Reliance Interest in Contract Damages”, the damages awarded by courts to those who have had a promise or contract broken is best understood as being proportional to the harm the plaintiff suffered in relying on the promise. These and other considerations argue for a theory of promises based on expectations and reliance, i.e., an expectational theory, as opposed to one based on conventions or natural duties, and this is what a number of philosophers and legal theorists have done. This debate has spawned a sizable literature (see Swain 2013 for a good overview of this work).