Although there is some difference of opinion, in general American pragmatists and Carnap reject bad metaphysics but at least for the former not metaphysics in general. Accordingly, the pragmatists leave the door open for good metaphysics. Heidegger, who is more radical, rejects metaphysics understood as ontology, conceived as identical to philosophy, hence rejects philosophy. Although these attacks on metaphysics in whole or in part have been influential, they are not obviously correct. Both the pragmatic and the Vienna Circle attacks on bad metaphysics from an empiricist angle of vision presuppose a form of verificationism.
Quine is an opponent of positivism who on analytic grounds has turned to pragmatism.
It is then significant that a commitment to verificationism is still maintained in attenuated form in Quine's naturalism. Yet the very criterion is, as has been pointed out, problematic since it is not itself empirically verifiable. Further, the attack on metaphysics as ontology seems to rest on an approach to ontology, namely the proposed ontological difference, which is difficult to defend and which is not clearly defended after Christian Wolff. This attack does not seem to affect, say Kant, or later writers such as Hegel, Husserl and many others. Finally, various attacks on epistemology presuppose a strong, Platonic conception of knowledge that can simply be abandoned without cost, as in the ongoing turn to pragmatism.