 Criticisms of the basic positions adopted in the Vienna Circle are legion, though it may be questioned whether most of them took account of the sophisticated variations on offer. (Sometimes the Circle’s own writings are disregarded altogether and “logical positivism” is discussed only via the proxy of Ayer’s popular exposition; see, e.g., Soames 2003.) But some Neo-Kantians like Ernst Cassirer may claim that they too accepted developments like the merely relative a priori and an appropriate conception of the historical development of science. Likewise, Wittgensteinians may claim that Wittgenstein’s own opposition to metaphysics only concerned false attempts to render it intelligible: his merely ineffable but uneliminated metaphysics concerned precisely what for him were essentials of ways of representing the world. The commonest criticisms, however, concerned not the uniqueness of the Vienna Circle’s doctrines, or their faithfulness to their supposed sources, but whether they were tenable at all. Prominent objects of this type of criticism include the verificationist theory of meaning and its claimed anti-metaphysical and non-cognitivist consequences as well as its own significance; the reductionism in phenomenalist or physicalist guises that appeared to attend the Circle’s attempted operationalisation of the logical atomism of Russell and Wittgenstein; and the Circle’s alleged scientism in general and their formalist and a-historical conception of scientific cognition in particular. These criticisms are discussed in some detail below in order to assess why which of the associated doctrines remain of what importance.