A discipline is defined by a domain of objects, a set of methods, a corpus of propositions considered to be true, a play of rules and definitions, of techniques and instruments: all this constitutes a sort of anonymous system at the disposal of anyone who wants to or is able to use it, without their meaning or validity being linked to the one who happened to be their inventor. (…)

But there is more; there is more no doubt in order for there to be less: a discipline is not the sum of all that can be truthfully said about something; it is not even the set of all that can be accepted about the same data in virtue of some principle of coherence or systematicity. (…)

Within its own limits, each discipline recognizes true and false propositions; but it pushes back a whole teratology of knowledge beyond its margins.

Michel Foucault, The Order of Discourse (1971)