Abstract

Discursive cognition of the sort that accompanies the grasp of a natural language involves an ability to self-govern by framing and following rules concerning what reason prescribes. In this essay I argue that the formal features of a planning semantics for the deontic and intentional modalities suggest a picture on which shared intentional mental states are a more primitive kind of cognition than that which accompanies the ability to frame and follow a rule, so that deontic cognition—and the autonomous rationality attending the ability to speak a natural language—might be understood as an evolutionary development out of the capacity to share intentions. In the course of defending this picture, I argue that it is supported by work in social psychology, evolutionary anthropology, and primatology concerning the phylogenetic and ontogenetic development of norm psychology and shared intentionality in human beings.