Michel Foucault

These pre-existing forms of continuity, all these syntheses that are accepted without question, must remain in suspense. They must not be rejected definitively of course, but the tranquility with which they are accepted must be disturbed; we must show that they do not come about of themselves, but are always the result of a construction the rules of which must be known, and the justifications of which must be scrutinized: we must define in what conditions and in view of which analyses certain of them are legitimate; and we must indicate which of them can never be accepted in any circumstances...

What we must do, in fact, is to tear away from them their virtual self-evidence, and to free the problems that they pose; to recognize that they are not the tranquil locus on the basis of which other questions (concerning their structure, coherence, systematicity, transformations) may be posed, but that they themselves pose a whole cluster of questions...

We must recognize that they may not, in the last resort, be what they seem at first sight. In short, that they require a theory, and that this theory cannot be constructed unless the field of facts of discourse on the basis of which those facts are built up appears in its non-synthetic purity.

The Archeology of Knowledge and The Discourse on Language