Critique, and especially radical critique of reason, is under pressure from two opponents. Whereas the proponents of »post-critical« or »acritical« thinking denounce critique as an empty and self-righteous repetition of debunking, the decriers of »post-truth« accuse critique of having helped to bring about our current »post-truth« politics. Both advocate realism as a limit critique must respect, but I will defend the claim that we urgently need radical critiques of reason because they offer a more precise diagnosis of the untruths in politics the two opponents of critique are rightfully worried about. Radical critiques of reason are possible, I argue, if we turn our attention to the practices of criticizing, if we refrain from a sovereign epistemology, and if we pluralize reason without trivializing it. In order to demonstrate the diagnostic advantage of radical critiques of reason, I briefly analyze the political and epistemic strategy at work in two exemplary untruths in politics.