This article contributes to the development of a rhetorical approach to the public understanding of science or science literacy. It is argued that rhetoric promises an alternative approach to deficit models that treat people as faulty scientists. Some tensions in the relevant rhetorical literature need resolution. These center on the application to science of an Aristotelian conception of rhetorical reasoning as enthymematic, without breaking from the Platonic/aristotelian division between technical and public spheres. The former opens science to the potential of (...) public critique; the latter closes this, effectively reinstating a deficit model. Gross’s writings are used to bring this point out sharply. A resolution is proposed, building on a view of rhetoric as socially constitutive and leading to a conception of public understanding as witcraft. Here, Billig’s rhetorical psychology provides the basis for reconfiguring the enthymeme in a manner that construes the division between spheres as itself rhetorically constituted. Creationism is used to provide brief illustration. (shrink)