 Encouraged by the chemical analogy, a central tenet in the study of speech acts is that content may remain fixed while force varies. The force of an utterance also underdetermines its content: Just from the fact that a speaker has made a promise, we cannot deduce what she has promised to do. For these reasons, students of speech acts contend that a given communicative act may be analyzed into two components: force and content. While semantics studies the contents of communicative acts, pragmatics studies their force.