A brief entry in Jerome’s Chronicle – the only Life of Lucretius surviving from antiquity – claims that he wrote De rerum natura ‘in the intervals of insanity’ before committing suicide. Jerome’s brief Life and its early modern accretions became a virtual blueprint for reading Lucretius’ poem in biofictional terms. De rerum natura was seen as a document of a mind divided against itself: the Life interacted with contradictions in the text to read Lucretius’ poem as a dramatized version of a modern subject facing the competing pressures of religion and its scientific other. This chapter looks at how Victorian readers engaged in biofictional receptions of De rerum natura as a means to thinking through psychological modernity. Lucretius’ popularity – as is now widely acknowledged – was crucial to the scientific culture of the period. But his Life and his poem were associated with another sort of inquiry: the psychological investigation of the human mind. Focusing on Matthew Arnold and Alfred Lord Tennyson, the chapter examines how these writers, in exploring the make-up of the human psyche at the crisis of modernity, used biofictional reading of Lucretius’ to work through contemporary cultural anxieties. The Roman poet was co-opted as an ersatz Victorian, and, in the process, modern subjectivity itself could be discovered.