Like Derrida, Foucault never sailed under the flag of ‘Post-Modernism’, or post-ism of any kind. They are rather different cases, and though Derrida was Foucault’s student at the Ecole Normale Supérieure, they appear to have had a long term falling out. This seems to have been more on Foucault’s side than Derrida’s. Despite Foucault’s expemplary qualities as thinker and libertarian social activist (future posts will return to the topic of Foucault and Libertarianism), he does seem to have been more prickly than Derrida. The prickliness seems to go all the way back to Derrida’s 1963 paper, ‘Cogito and Madness’ (collected in Writing and Difference), which is a critical but appreciative discussion of Foucault’s Madness and Civilisation.
The stereotypical view of Foucault circulated by his ‘Analytical’ philosophical critics and his ‘Post-Modern’ fans (more typically to be found in humanities and social science departments other than philosophy) is that he was a relativist who denied the existence of truth or objective, knowledge, and that he had a related assumption according to which reality only exists as a discursive social construction serving power interests of some kind. Something similar to that ‘Post-Modern’ interpretation of Foucault is also widespread in interpretation of Thomas Kuhn, a leaidng figure in Philosophy of Science in the Analytic tradition. Again very different cases, but there is no more reason to think of Foucault as a Post-Modernist than there is to think of Kuhn in that way.
There are many issues to be explored in future, but just one for today. Just a remark that one of Foucault’s most widely read books, Discipline and Punish, does refer to the discourses of power/knowledge, but it also refers to discourse as what affects the body. There is something pre-discursive in Foucault, the body. There is no ‘body’ or ‘nature’ we can identify from outside discourse for Foucault, but physicality and natural forces are there. His view of power/knowledge is just as much an attempt to think of social relations in terms of natural forces, as a discourse centred theory. The body is experienced in social and discursive contexts, but is not eliminated as a body. It is the body where there is resistance to power.