Building on a careful truth-conditionalist semantics for 'ought' considered as a modal word, Chrisman argues that ought-sentences mean what they do neither because of how they describe reality nor because of the noncognitive attitudes they express, but because of their inferential role.



The word 'ought' is one of the core normative terms, but it is also a modal word. In this book Matthew Chrisman develops a careful account of the semantics of 'ought' as a modal operator, and uses this to motivate a novel inferentialist account of why ought-sentences have the meaning that they have. This is a metanormative account that agrees with traditional descriptivist theories in metaethics that specifying the truth-conditions of normative sentences is a central part of the explanation of their meaning. But Chrisman argues that this leaves important metasemantic questions about what it is in virtue of which ought-sentences have the meanings that they have unanswered. His appeal to inferentialism aims to provide a viable anti-descriptivist but also anti-expressivist answer to these questions.