It is surely the following kinds of question that would need to be posed: What types of knowledge do you want to disqualify in the very instant of your demand: 'Is it a science'? Which speaking, discoursing subjects -which subjects of experience and knowledge - d you then want to 'diminish' when you say: 'I who conduct this discourse am conducting a scientific discourse, and I am a scientist'? Which theoretical-political avant garde do you want to enthrone in order to isolate it from all the discontinuous forms of knowledge that circulate about it? When I see you straining to establish the scientificity of Marxism I do not really think that you are demonstrating once and for all that Marxism has a rational structure and that therefore its propositions are the outcome of verifiable procedures; for me you are doing something altogether different, you are investing Marxist discourses and those who uphold them with the effects of a power which the West since Medieval times has attributed to science and has reserved for those engaged in scientific discourse.
Michel Foucault Power/Knowledge: Selected Interviews and Other Writings