The notions of "presupposing" and of contextual implication, which we shall compare and contrast in what follows, have come to play increasingly prominent roles in the philosophical literature of the English-speaking world since the 1940s. This development is not accidental but arises from the stress the twentieth century put upon analysis as a fundamental mode of philosophical inquiry. The notions of presupposing and of contextual implication play both negative and positive roles within this general orientation. Negatively, they are devices that contemporary thinkers employ in order to minimize the tendency of philosophers and other reflective persons to view the world in terms of oversimplified conceptual models. Positively, they function as instruments in the dissection and ultimate understanding of certain human activities, especially those that involve the efforts of human beings to communicate with one another, as in promising, stating, saying, implying, a task that, some philosophers feel, is...