By giving a central place to the treatment of justice in an epic narrative, Paradise Lost arguably intervenes in the “ancient quarrel” between poetry and philosophy. The juxtaposition of mode and topic is striking because the text most famously associated with the indictment of poetry, and Homer specifically, was also one of the most influential ancient philosophic treatments of justice: Plato’s Republic. I contend that the explicit treatment of justice as a topic in the opening books of Paradise Lost is, in effect, part of a larger attempt to “justify the ways of Poets to Plato.” The first stage of this presentation draws on Peter Mack’s account of how renaissance rhetorical education engaged early modern discourses of ethical deliberation. The second part of the argument traces how the first books of Paradise Lost include no less than six points of direct engagement with parallel claims advanced in the Republic. In each case, Paradise Lost either articulates or explicitly dramatizes a given claim made in Plato’s text. Ultimately this opening book of Paradise Lost implies that a specific kind of union between poetic narrative and dialectical inquiry best illuminates questions concerning justice—most notably, questions regarding the character of tyranny and virtuous appearances.