The set of relations between discursive positivity, knowledge, and science that archeological analysis examines at the threshold of epistemologization (see above) is the episteme. The episteme is not itself a form of knowledge, and it has no general content in and of itself; it is not a world- view or ‘a slice of history common to all branches of knowledge’ in a given period. The term refers only to a level of relations involving knowledge and science as they emerge within a discursive positivity; these relations are various and shifting, even for a single period. This term, which Foucault introduces in his book The Order of Things, refers to the orderly ‘unconscious’ structures underlying the production of scientific knowledge in a particular time and place. It is the ‘epistemological field’ which forms the conditions of possibility for knowledge in a given time and place. It has often been compared to T.S Kuhn’s notion of paradigm.