As an abstraction that identifies the inner thinking self, the mind is a powerful resource for rhetorical invention, enabling both the generation of discourse and epistemic sense-making. This dissertation provides insight into the discursive life of “the mind,” examining how different instantiations of the concept were put to rhetorical use in three specific historical cases. In each case study, I examine a conception of the mind that originated in the realm of institutional science and that made its way into public culture, often circuitously, and frequently transformed in the process. The first case study analyzes a nineteenth-century phrenology handbook, which reveals how the phrenological mind enabled pre-existing cultural beliefs to be resourced, or respoken as if the objective results of science. The second case study examines Benjamin Spock’s use of Freudian ideas to generate child-rearing advice in his classic Baby and Child Care manual. My analysis of Spock’s Freudianism leads me to propose that beliefs about the mind constitute a uniquely generative class of doxa that I label “psychodoxa.” The final case study focuses on the contemporary cerebral self, which asserts the isomorphism of mind, brain, and self. This conception of mind generated considerable interest in Terri Schiavo’s brain in the end-of-life case that dominated news media in the early 2000s, and I suggest that much of the discourse concerning Schiavo’s brain relied on recalcitrance to channel invention. The dissertation concludes by considering the mind’s utility as an inventional resource for rhetoric itself.