Book excerpt: What does talk of meaning mean? All thinking consists in natural happenings in the brain. Talk of meaning though, has resisted interpretation in terms of anything that is clearly natural, such as linguistic dispositions. This, Kripke's Wittgenstein suggests, is because the concept of meaning is normative, on the 'ought' side of Hume's divide between is and ought. Allan Gibbard's previous books Wise Choices, Apt Feelings and Thinking How to Live treated normative discourse as a natural phenomenon, but not as describing the world naturalistically. His theory is a form of expressivism for normative concepts, holding, roughly, that normative statements express states of planning. This new book integrates his expressivism for normative language with a theory of how the meaning of meaning could be normative. The result applies to itself: metaethics expands to address key topics in the philosophy of language, topics which in turn include core parts of metaethics. An upshot is to lessen the contrast between expressivism and nonnaturalism: in their strongest forms, the two converge in all their theses. Still, they differ in the explanations they give. Nonnaturalists' explanations mystify, whereas expressivists render normative thinking intelligible as something to expect from beings like us, complexly social products of natural selection who talk with each other.