Rarely is speech simply a medium of communication, the channel along which a message is transmitted from A to B. As ancient rhetoricians understood well, it is the formation of a relationship between a speaker, the audience, and the issue around which persuasion is sought. That relationship shapes the audience’s reception of the speaker and disposes it in particular ways towards the message conveyed. Rhetorical knowledge, then, consists less in advice concerning the truthfullness of the message (as aggrieved philosophers such as Plato complained) than instruction on how an overall performance discloses aspects of the issue, casting it in a certain light and positioning the audience towards the matter in a particular way. Consequently, rhetoric gained a reputation as a mischevious kind of instruction concerned with the play of light and shadow, inviting speech to obscure as much as it illumined.