« Is Feyerabend post-modern? »
I think this constitutes a bad question, given that the term « post-modern » itself is quite ambiguous. However, Feyerabend frequently emphasised the importance and inevitability of ambiguity, declaring that the awareness of and ability to work with ambiguity is what he had in common with the deconstructionists. So it seems reasonable to attempt an answer if we bear in mind its ambiguity and its potential fecundity.
« Post-modern » is used to name a wide spectrum of ideas and positions, ranging from epistemological relativism to ontological pluralism. Lyotard is often misquoted on this point: he defined post-modernism as the decline of grand narratives of legitimation. This is often reduced to the « decline of grand narratives », without including the qualification « of legitimation ».
Lyotard’s conception of the « post-modern » is exactly the same as Feyerabend’s concept of epistemological anarchism. Feyerabend’s argument in AGAINST METHOD is not opposed to all methods, but only against the use of Method as legitimation for the derivation of rules for scientific progress having prescriptive, rather than heuristic, force and guaranteeing progress.
Feyerabend was aware of Lyotard’s book THE POSTMODERN CONDITION, and he cites it favorably in the introduction to FAREWELL TO REASON. Lyotard cites Feyerabend’s work on a number of occasions. I can further attest that I met Lyotard in 1980, shortly after the publication of THE POSTMODERN CONDITION, and I discussed Feyerabend with him. He was quite a fan, declaring « J’adore Feyerabend! ».
Beyond this anecdotal level, what unites them more fundamentally is that both Lyotard and Feyerabend were hostile to the facile relativism that passes for « postmodern » and were eager to elaborate a conception that would allow for plurality while allowing us to combat the relativist tolerance for anything and everything.