 More bothersome is that the key concept here is an unexplained and seemingly unexplainable one. No one has provided a rigorous definition of a speech act. Even these many years after Austin first introduced the concept in the 1950s, little more has been done to clarify and ground it than to cite some handy examples, place the foils of locutionary and perlocutionary acts to the left and right of it, and invoke the “in” versus “by” distinction found above and in virtually every other exposition of the notion. Most philosophers are at least somewhat hesitant to make a concept that’s technical yet so little explained or pinned down the mainstay of a substantial theory, such as a theory of meaning.