Michel Foucault's The Archaeology of Knowledge (1969) presents a rigorous treatise on the methodology and historiography applicable to systems of thought (epistemes) and discursive formations. This framework posits that knowledge is structured by unconscious rules that operate beneath individual consciousness, thereby establishing a conceptual system of possibility which pre-conditions and delimits the boundaries of language and cognition within specific historical and disciplinary domains. Foucault had previously deployed this "archaeological" analytical method in seminal works such as Madness and Civilization (1961), The Birth of the Clinic (1963), and The Order of Things (1966). Diverging significantly from conventional History of Ideas, which often relies on narrative continuities and the identification of seemingly discrete knowledge modes, Foucault's archaeology instead emphasizes the discontinuities and the intricate interplay of discursive and institutional relationships that govern the emergence and transformation of knowledge, rather than its linear evolution.

Central to this methodology is the concept of the énoncé (statement), defined not merely as a linguistic expression but as the set of operative rules that imbues a phrase, proposition, or speech act with discursive meaning, a dimension distinct from mere signification. Crucially, an énoncé's discursive meaning is contingent upon an existence function, requiring a relation to an extra-discursive reality; for instance, the expression "The gold mountain is in California" lacks discursive meaning if it is unrelated to actual geographic conditions. While syntax and semantics provide rules for significative correctness, they are demonstrably insufficient for determining discursive meaning; an expression can be grammatically flawless yet discursively meaningless, or conversely, grammatically incorrect but profoundly discursively meaningful (e.g., "QWERTY" as a keyboard layout identifier). The discursive meaning of an expression is intrinsically determined by its conditions of emergence and existence within the specific network of statements constituting a field or discipline, with its validity established by preceding and following statements. Therefore, énoncés form a pre-conditioning network of rules that establish which expressions are discursively meaningful, thus enabling signifying propositions, utterances, and acts of speech to acquire discursive validity. The archaeological analysis consequently focuses on the organized dispersion of these statements and the resulting discursive formations, offering a potent method for historical inquiry.