A discursive formation is defined by regular differences among statements, not uniformity.
Evidence
The statements within a discursive formation need not all be the same. But the relationships and differences between them must be regular and systematic, not random. Foucault calls this a “system of dispersion”: “Whenever one can describe, between a number of statements, such a system of dispersion, whenever … one can define a regularity … [then] we will say … that we are dealing with a discursive formation” (1972, 38; emphasis in original).
— Stuart Hall, Essential Essays, Volume 2, 573
Categorization
DEFINE: Defines Foucault’s “system of dispersion” — a technical term the reader needs in the toolkit.