Twelve years ago I drew attention in a paper to the importance of the discovery of performative utterances by the well known Oxford linguistic philosopher, John Austin, for a better understanding of the legal concept of contract.\u27 In The Legal Point of View, I developed this concept into what I called the performative function of discourse,2 and in a recent paper I applied it to rebut an attack on the objective theory of contract. 3 My main aim in the present paper is to compare Austin\u27s classification of infelicities, to which performative utterances are subject, with their legal analogues. Although it is unlikely that Lord Denning was familiar with Austin\u27s concept of performative utterances, the recognition of the performative function of discourse lends strong support to his doctrine of equitable mistake. 4 This example shows well how doctrinal development in the law may be strengthened by keeping abreast of developments in philosophy, and how it may be weakened by failing to do so. The philosophical repertoire of most lawyers is usually antiquated, if not quaint. The same is true of the legal repertoire of philosophers. Yet, philosophers on the whole are more willing to learn from lawyers than the other way round. Thus, Austin explicitly acknowledges that the nearest approach to performative is the word operative as used by lawyers, the operative part of a legal instrument being that part which actually performs the legal act which it is the purpose of the instrument to perform. 5 He also refers to contributions made by lawyers in his discussion of infelicities.
