The article discusses two passages,Republic IX 571d6–572b1, andTimaeus71a3–72b5, where Plato does not use dream as a metaphor for the soul’s deficit in knowledge but, instead, focuses on the actual process of dreaming during sleep, and the origin and nature of the images involved. In both texts, Plato’s account is closely connected to the soul’s tripartition, with the resulting emphasis on reason’s capacity to control, and even to create, the dream images that influence the lower parts of the soul. While taking (...) a closer look at the differences between the two accounts (and, therefore, at the physiology of dreaming described only in theTimaeus), the article concludes that, despite these differences, both dialogues agree on the possible alliance between reason and dreaming, an alliance that presupposes a virtuous character and further reinforces the reason’s dominance over appetite.Republic IX and theTimaeusthus converge on the idea that dreams, in virtue of their continuity with waking thoughts, can convey and fortify a certain kind of knowledge, and especially self-knowledge, which is of an ethical rather than strictly epistemic relevance. This is also why Plato’s two accounts of rational dreaming anticipate the issue of our moral responsibility for the content of our dreams. (shrink)