 Descartes’ commitment to innate ideas places him in a rationalist tradition tracing back to Plato. Knowledge of the nature of reality derives from ideas of the intellect, not the external senses. An important part of metaphysical inquiry therefore involves learning to think with the intellect. Plato’s allegory of the cave portrays this rationalist theme in terms of epistemically distinct worlds: what the senses reveal is likened to shadowy imagery on the wall of a poorly lit cave; what the intellect reveals is likened to a world of fully real beings illuminated by bright sunshine. The metaphor aptly depicts our epistemic predicament given Descartes’ own doctrines. An important function of his methods is to help would-be perfect knowers redirect their attention from the confused imagery of the senses to the luminous world of clear and distinct ideas of the intellect.