Commentators have found many flaws with this argument, starting from Lyotard’s stretching of the word “narrative” into shapes that are unrecognizable (a flaw he himself freely admitted, though he continued to stand by its usefulness for his purpose). More important, though, his critics have noted that the descriptions of science provided by Kuhn and Feyerabend are not descriptions of “postmodern” science but of science in general. Furthermore, the science Lyotard seems to champion is not so cheerfully postmodern as he would have it; it has not entirely abandoned “grand narratives” but merely set them aside, while the work for such things as a unified field theory (which would explain the unity of the four basic forces of nature) goes on.
Finally, many commentators have had trouble avoiding the self-evident contradiction in Lyotard’s account. The Postmodern Condition tells a metanarrative about the demise of the metanarrative. Thus, Lyotard is caught in exactly the trap in which he claims science is caught when it seeks to legitimate itself through narrative or avoid legitimating itself all together. If his narrative is credible, it proves him wrong because it itself is a metanarrative. If, on the other hand, metanarratives really had lost all credibility, Lyotard would have no credulous way of saying it. In sum, for his narrative to speak with authority, it has to speak with no authority, an ironic contradiction that does not entirely discount his work but does imply that the straightforward narrative form he used for The Postmodern Condition is not finally able to contain what he wants it to contain, therefore making the far more obscure, playful, and aphoristic style of The Differend almost a necessity.