What does it mean to say what you think? In Between Thought and Expression, Eric Marcus argues that the relationship between a thought and its expression in language is more intimate than philosophers have supposed. We do not first form a belief, intention, or desire, and then find words to report it; rather, the ability to put a thought into words is part of what makes it the thought it is, and a rational creature's thought is no more determinate than her ability to articulate it. Understanding what someone is saying is therefore not a matter of inferring the speaker's state of mind from the words she utters, but of grasping the sense she is making with them. Variants of Moore's Paradox^&#8212conjunctions of independently meaningful statements that somehow fail to make sense^&#8212are shown to arise across a striking range of domains: intentional action, desire, moral exhortation, aesthetic judgment, and validity. Tracking these Moore-style phenomena, Marcus argues that our attitudes in each domain are partly constituted by the thinker's capacity to avow them^&#8212a capacity whose exercises, properly understood, are themselves applications of the standard of appropriateness to which the attitude is answerable. Through seven examples of a single phenomenon^&#8212independently meaningful statements that somehow fail to make sense in combination^&#8212Marcus develops this thesis across belief, action, desire, moral advice, aesthetic judgment, and logical inference, offering a unified picture of the rational mind.