 In the last two decades, there has been a burgeoning number of researchers investigating conversational implicature and Grice’s principles. Criticisms have come from two opposing directions. Some critics argue that Grice’s maxims are not sufficiently worked out to explain many of the phenomena related to implicature. For example, in the sentence, “Joan believes that some of her students will fail,” there seems to be an implicature that not all of her students will fail, even though the contained sentence is not asserted. In another direction, Wilson and Sperber, and separately Bardzokas, argue that Grice’s principles can be derived from more general principles and should be understood in the context of some version of relevance theory.