H. argues that a theory of a language that attempts to capture the competence of that language should not associate sentences with universal semantic representations (encoding prelinguistic thoughts and ideas). An adequate theory will have five components: a grammar assigning interpreted logical forms to sentences; a logic stating the principles of logical implication holding among sentences given the purely logical aspects of their logical forms; axioms representing meaning postulates or the common knowledge among speakers; a theory of conversation including an account of presupposition, implicature and speech acts; a theory of conceptual role indicating the role of expressions in relation to theoretical and practical thinking, observation, and behavior.