Although existing scholarship has occasionally acknowledged the importance of fantasy as the primary internal sense in Juan Luis Vives’s (1492/93–1540) account of the soul in De anima et vita (1538), the conceptual reasons behind its significance remain unknown. This article argues that the prominence given to fantasy in De anima can be read as a reflection on the larger presuppositions of Erasmian ethical, political, and rhetorical thought. Since fantasy held a key position between the bodily and the rational, the understanding of its functions was of pivotal importance for the practices of ethical self-governance central to all Erasmian moral and political philosophy. Simultaneously, fantasy occupied a central place in the rhetorical literature of the time, since it was through visual representations that the mind of the audience could be cultivated or reached. The moral philosophical and rhetorical uses of fantasy have an explicit political dimension since phantasia played a significant role in the formation and counsel of rulers.