Contrary to Samuel Williston’s description of the ALI’s formal restatement of contract law as merely presenting the law ‘as it is, not as a new law’, the doctrine of promissory estoppel set forth in Section 90 thereof does not represent an ancient principle of contract law. Rather, it constitutes a relatively recent and largely artificial innovation by Williston and his colleague Arthur Corbin. To overcome potential objections to such novelty, Williston and Corbin advocated for their new doctrine on the basis of specific claims of historical authority therefor. In particular, they asserted that promissory estoppel was doctrinally and philosophically consonant with the origins of English contract law during the Middle Ages. Those claims are not well-founded.
Specifically, Williston, Corbin and other proponents of promissory estoppel have focused on the fact that during the period from roughly 1350 to 1600 litigants and courts incrementally turned for the enforcement of contract to the tort writ of trespass on the case sounding in assumpsit in substitution for the use of well-established, preexisting contractual writs. Yet these proponents of promissory estoppel have ignored the underlying reasons for, and limitations of, that historical development. Contrary to their implication, there occurred no fundamental doctrinal rejection of preexisting contract law, to which the doctrine of promissory estoppel would have been wholly alien. Rather, this circumvention of the preexisting contractual writs by means of assumpsit came to pass as the direct result of specific jurisdictional and procedural limitations that had hobbled the use of those contractual writs.
Moreover, and critically, both prior to and during the period of this creative extension of assumpsit the fundamental principle of reciprocity in contract was repeatedly asserted by the courts and commentators. The major extension of assumpsit in the mid-1500s into the realm of the principal preexisting contractual writ for informal contracts, debt upon contract, was temporally coupled with and limited by this principle, which came to be expressed as the doctrine of consideration. Promissory estoppel, which rejects at its core the principle of reciprocity in contract, is antithetical to this history.
Alden, Eric, Promissory Estoppel and the Origins of Contract Law (February 1, 2016).