There has been a recent resurgence of interest in the subject of rhetoric, including within economics. The purpose of the paper is to focus on the ideas on rhetoric of Adam Smith and his contemporaries (particularly Hume) in relation to their philosophy and economics, against the background of the Scottish Enlightenment. Discussions of language in Scotland at that time departed from what had become a conventional emphasis either on persuasion or on style in order to focus on a broader notion of communication which encompassed both. This followed from a focus on language differences within a united Britain. But for Smith it also followed from his moral philosophy, whereby communication was important as a vehicle for persuasion in the absence of scope for argument by demonstrable proof. He was thus concerned to set up a system of rhetoric. Smith distinguished between the derivation of (provisional) knowledge by the Newtonian experimental method, and the communication of that knowledge as if it were based on derivation from first principles. Subsequent (mis)interpretation of Smith’s economics can be understood as stemming from mistaking the rhetoric for the method, and interpreting first principles as axioms. A fuller understanding of Smith’s views on communication and the role of sympathy (through imagination) might have led to different understandings of Smith’s economics prevailing.