This paper examines Anscombe’s theory of promises, especially the new obligation generated from promises. Firstly, I introduce a possible challenge that there are two seemingly contradictory kinds of necessity in her discussion of promises (Section 1). Then, I analyze these two kinds of necessity: the conventional necessity which indicates that the obligation is based on conventions and not naturally intelligible (Section 2); the Aristotelian necessity without which some good cannot be attained (Section 3). At last, I present Anscombe’s notion of “human linguistic practice” and related practical necessity as her answer to this seeming contradiction (Section 4). My aim is to demonstrate how the notion of “human linguistic practice” can be employed to defend the consistency of Anscombe’s theory of promises.
