 Austin’s student, John R. Searle (1969) developed speech act theory as a theory of the constitutive rules for performing illocutionary acts, i.e., the rules that tell what performing (successfully) an illocutionary act (with certain illocutionary force and certain propositional content) consists in. The rules are classified as (i) propositional content rules, which put conditions on the propositional content of some illocutionary acts; (ii) preparatory rules, which tell what the speaker will imply in the performance of the illocutionary acts; (iii) sincerity rules, that tell what psychological state the speaker expresses to be in; and (iv) essential rules, which tell us what the action consists in essentially.