Based on certain passages in Colotes, Hermarchus, and Horace, the Epicureans may be thought to defend a social contract theory that is roughly Hobbesian. According to such a view, human life without the social contract is solitary and brutish. This paper argues that such a reading is mistaken. It offers a systematic analysis of Lucretius’s culture story in On the Nature of Thingsv as well as the Epicurean passages that at first sight seem to contradict the Lucretian account. The conclusion of such an analysis is not only that all extant evidence is internally consistent, but also that Epicurean social contract theory relies on a ‘dynamic’ conception of human nature: On the Epicurean view, agents have very different psychological motivations when coming together to form societies and when coming together to form political and legal states.