The condition in which elements, concepts, genres, or rhetorical practices from distinct discourses intersect or are embedded within a single text or communicative practice, producing hybrid meaning by linking different domains of knowledge, authority, or practice.

Principle

Interdiscursivity functions by transferring or re‑framing terms, evidentiary forms, or rhetorical authorities from one discourse into another; the hybrid meaning depends on both the source discourses' criteria and the way they are combined or subordinated in the receiving context.

Demonstration

Illustrative scenario: A policy brief integrates statistical models, medical terminology, and moral rhetoric to justify a recommendation. Readers evaluate the recommendation by attending to the interplay: the scientific form grants predictive authority, while ethical language frames values—together they produce a multidisciplinary warrant that neither discourse supplies alone.

Misapplication

Error: Treating any quotation or reference across fields as interdiscursivity. Why it seems plausible: cross‑disciplinary citation is common. The semantic error: conflating mere citation or metaphor with true discursive intersection that reshapes argument structure and standards of evidence.

Consequence

Interdiscursivity expands interpretive frames and can legitimize claims by drawing on multiple authorities; it also creates risks of category confusion, mismatched standards of evidence, and the need for interdisciplinary competence to assess claims properly.

Reversal

When one discourse fully subsumes another without preserving its criteria (e.g., applying rhetorical techniques while discarding the original epistemic standards), apparent interdiscursivity can mask epistemic colonisation rather than genuine dialogue; conversely, careful boundary‑preserving translation can limit hybridisation.

Boundary

Clearly within: a medical guideline that incorporates legal obligations and statistical risk estimates into its recommendations. Boundary case: a literary essay that uses scientific metaphor transiently—classification depends on whether scientific discourse is used as evidential framework or as figurative language. Clearly outside: a discipline‑specific technical report that remains within a single, consistent discourse and set of evidentiary standards.

Semantic Tension

Epistemic rigor ↔ Rhetorical persuasiveness — interdiscursivity trades off the methodological standards of specialized disciplines against the rhetorical power gained by combining registers.

Synthesis

Interdiscursivity is a mechanism of meaning‑making that reorganises authority: it creates hybrid warrants by relocating discursive resources across boundaries, demanding scrutiny of which criteria travel intact and which are transformed or lost.