Source: “Border lines : The Partition of Judaeo-Christianity” By Daniel Boyarin, University of Pennsylvania Press. 2004
This introductory podcast argues that the perceived borders between Christianity and Judaism were not natural, but rather constructed through discourse, much like political borders. The author proposes that the development of heresiology, the defining of "orthodox" belief against "heretical" ideas, was a primary force in this separation, acting as "customs inspectors" to police religious boundaries. This process of creating distinct religious categories, with Christianity inventing the very notion of "religion," led to Judaism's later ambiguous status as both a religion and something more, a dynamic the book will explore through historical texts and theories of identity and categorization.
The Construction of the Border Between Christianity and Judaism: The source argues against the idea that Christianity and Judaism naturally grew apart in a "parting of the ways." Instead, it proposes that the border between them was actively constructed and imposed, much like political or colonial borders such as the US-Mexico border or the partitions of India and Palestine. This border was artificial and political, created by dominant forces rather than reflecting a natural separation of pre-existing, distinct entities. The author uses the humorous anecdote of the wheelbarrow smuggler to illustrate this, suggesting that what was truly being "smuggled" across the border wasn't the obvious content, but the very concept of the border itself and the categories it created.
Heresiology as the Mechanism for Defining and Policing Boundaries: The central technology for constructing this border and differentiating Judaism from Christianity was heresiology. Heresiology, defined as the "science" of heresies, involved inscribing border lines and identifying those who crossed them. Heresiologists, acting as "customs inspectors" or "religion police," sought to identify and prevent the movement of "contraband"—people, religious ideas, practices, and innovations—across the newly defined boundaries. They aimed to eradicate the semantic and social "fuzziness" between Jews and Christians to produce them as fully separate and opposed entities. Groups and practices deemed threatening to the desired purity of the emerging categories were labeled as hybrid or heretical.
The Invention of Heresy and the Category of "Religion": The source traces the historical development of the concept of "heresy" (hairesis). Initially, hairesis simply meant a "choice" or an affinity group sharing common ideas. However, the source, building on the work of others, suggests that Christian writers like Justin Martyr were crucial in transforming this term to mean a group outside established tradition that propounds false doctrine. This invention of heresy is intimately linked to the invention of "religion" itself as a discrete, disembedded category of human experience. Christianity, in its process of formation and self-definition, produced "religion" as a category and needed to differentiate itself from its origins and neighbors, particularly Judaism, thereby constituting Judaism as a distinct "other" religion.
Orthodoxy and Heresy as Mutually Constitutive Notions: The source emphasizes a modern scholarly shift away from viewing orthodoxy and heresy as fixed "essences" or pre-existing doctrines. Instead, drawing on post-structuralist thought, it proposes that orthodoxy and heresy are notions that are defined in relation to each other and come into the world of discourse simultaneously. They are not things that exist independently, but rather concepts used within a particular discourse (heresiology) to define who is "in" and who is "out" of a religious group based on shared ideas, practices, or beliefs. This perspective challenges earlier historical accounts that assumed orthodoxy simply preceded heresy or vice versa.
Hybridity and the Disavowal of Difference: The border space between Judaism and Christianity was inherently a zone of hybridity, where people, ideas, and practices mingled. However, the discourse of heresiology sought to suppress this hybridity by designating it as unnatural or monstrous. By labeling certain groups or practices as hybrid (e.g., "Judaizers," minim), heresiologists externalized internal differences and ambiguities, thereby reinforcing the illusion of purity and distinctness for the emerging orthodox categories. Heresiology, in this sense, functioned as a form of "apartheid comparative religion," creating rigid categories to manage the complexity of the "frontier zone" and control human diversity.
Wave Theory as an Alternative to the "Parting of the Ways" Narrative: To better understand the relationship between early Christianity and Judaism, the source advocates for a "wave theory" model, borrowed from historical linguistics, over the traditional "Stammbaum" (family tree) model. The Stammbaum model assumes a common origin and subsequent divergence, fitting the "parting of the ways" narrative. Wave theory, conversely, does not require a single origin point and explains similarities as products of diffusion and convergence in contiguous areas, where boundaries are fluid and not strictly defined. This model helps conceptualize Judaism and Christianity initially as clusters of religious "dialects" within a broader "Judaeo-Christianity," which gradually became organized into distinct "languages" (religions) through processes analogous to the formation of national languages.
Logos Theology as a Case Study in Border Construction: The source uses the concept of Logos theology as a prime example of how a shared theological idea became a crucial distinguishing marker between Christianity and Judaism. This doctrine, involving a second divine entity mediating between God and the world, was present in various forms within pre- and pararabbinic Judaism and was debated within early Christianity. The source argues that Christian heresiologists, such as Justin Martyr, actively constructed belief in the Logos as essential to Christian orthodoxy, while simultaneously, rabbinic authorities effectively ceded this concept to Christianity and defined Jews who held similar binitarian ideas as heretics (minim or proponents of "Two Powers in Heaven"). This mutual process resulted in the "crucifixion of the Logos," making its acceptance a touchstone for Christian identity and its rejection a touchstone for Jewish identity, thereby theologically dividing the two groups.
Judaism's Ambivalent Status as a "Religion": The source contends that the term "Judaism" as a name for a "religion" is largely a product of the Christian invention of religion and is fundamentally a Christian category. There was no equivalent term or concept in pre-modern Jewish parlance, where Jewish identity encompassed a whole complex of loyalties, practices, ethnicity, nationality, and history (Ioudaismos in 2 Maccabees referred to this entire complex, not just "religion"). While Christianity configured Judaism as a different religion, the source suggests that classical rabbinic Judaism ultimately refused this interpellation. This refusal to be defined solely as a "religion" accounts for Judaism's historical and contemporary ambivalence, sometimes operating as a religion in multireligious contexts but also maintaining aspects that resist separation from ethnicity and peoplehood.
Interpellation and the Creation of Identity: Drawing on theories of interpellation, the source explains how being addressed or named by a dominant discourse can injure but also paradoxically summon a subject into existence, enabling self-definition and even resistance. Just as being called "queer" can create a subject who uses that term to counter offense, being called "Jew," "Christian," "heretic," or "pagan" by Christian authorities played a role in the formation of these identities. The source cites examples like Athanasius's "hate-speech" potentially calling a Jewish subject into existence and Christian discourse on "paganism" leading certain Roman groups to consolidate their identity as a "religion," arguing that Jewish identity was also shaped by this process of being named by the Christian other.
Systemic Change and Mutual Construction: The historical developments leading to the differentiation of Judaism and Christianity are viewed within the context of shared systemic changes in late antiquity, driven by common political, social, and economic forces. This perspective suggests that the emergence of rabbinic Judaism and Christian culture were sibling processes. Instead of one tradition simply influencing the other, both underwent transformations that were mutually constitutive. The emergence of orthodoxy and heresiology, for example, is seen as part of a broader sociocultural process where earlier sectarian structures were becoming less viable. This mutual construction resulted in Judaism and Christianity ultimately becoming "two different kinds of things altogether," with asymmetrical understandings of Judaism itself—Christianity seeing it as a religion, and rabbinic Judaism refusing that category.