Introduction

      The terms “Christianity” and “Judaism” are difficult for students of these ancient religions. Church historians remain unable to pinpoint once and for all the emergence of “Christianity” from “Judaism”; scholars of Judaic studies debate when Judaism was “invented.”¹ “Christianity” and “Judaism” can feel like vacuous terms that house a great diversity of groups, practices, and ideas whose differences seem to outweigh their resemblances. Consequently, some scholars feel more comfortable discussing Christianities and Judaisms, and nobody is comfortable with the term used for groups that exist on the borderlines between them: “Jewish-Christian”(!).² Even more problematic is the term “paganism,” which is essentially a wastebasket for the religious life of every ancient person who did not identify with a cult of the God of Abraham. Yet we persist in using these terms, despite our misgivings, and not just as a heuristic sleight-of-hand. Sometimes there are significant differences between various groups and their ideas, differences that do correspond somewhat to the way that we moderns might use the terms “Jewish” or “Christian” or “Hellenic” (“pagan” I renounce in this book).³ These differences did not fall from the sky. They were manufactured, in words, art, and ritual, by cultural warriors who believed that such differences mattered and used them to legitimize their own interests.

      This book is about some of those real differences and the development of the ideologies that crafted them—in this case, the competing worldviews of “Christian” and “Hellenic” (i.e., Greek) philosophers. It argues that one can identify when and where these worldviews split for good: in the 260s CE, in Rome, in the reading group of the great Neoplatonic philosopher Plotinus. The master had a falling out with some of the Christian interlocutors of the group, sparked by the texts they read. After this controversy at the onset of late antiquity, it becomes very difficult to find academic, Hellenic philosophers with cordial relationships with their Christian counterparts. Instead, they regularly wrote polemical treatises denouncing each other’s philosophy (even while still exchanging ideas). Here it becomes meaningful to talk of a Christian philosophy distinct from Hellenic philosophy—as a matter of cultural identity as well as intellectual enterprise—and a closed Platonic tradition, unfriendly to Jewish and Christian sources.

      Unfortunately, this story gets (very) complicated when we try to learn about the Christian interlocutors of Plotinus and their controversial texts, and it is largely occupied—as is the bulk of this book, really—with what we know about them and, in turn, what these details tell us about the situation in Plotinus’s circle. Fortunately, these details are not uninteresting: in fact, they furnish valuable evidence for deepening our understanding of an obscure Judeo-Christian literary tradition, Sethianism (so called due to its focus on the figure of Adam and Eve’s third son, Seth, as savior and revealer). This book explains the contribution of Sethianism to Greek philosophy, and the reasons for its subsequent exile from the Hellenic schools; its relationship to Judaism, Christianity, and the “Jewish-Christian” groups that existed in the cracks between them; and the development of Jewish mystical traditions we know from the apocalypses and Qumran. This same tradition provides the most valuable evidence modern scholars possess for understanding the thought, background, and historical importance of any group of Gnostics—early Christians who were associated by their opponents with a myth of the creation of the world by a demiurge (“craftsman”) of ambivalent ability and mores.⁴ It appears that these sects referred to themselves as γνωστικοί (“knowers”).

      Plotinus’s student Porphyry provides our only record of a personal encounter with ancient Gnostics that does not come from one of their bitter opponents among the church fathers:

      There were in his (Plotinus’s) time many others, Christians, in particular heretics who had set out from the ancient philosophy, men belonging to the schools of Adelphius and Aculinus—who possessed many texts of Alexander the Libyan and Philocomus and Demostratus of Lydia, and who produced revelations of Zoroaster and Zostrianos and Nicotheus and Allogenes and Messos and others of this sort who deceived many, just as they had been deceived, actually alleging that Plato really had not penetrated to the depth of intelligible substance. Wherefore, Plotinus often attacked their position in his seminars, and wrote the book which we have entitled “Against the Gnostics.”