 By contrast, Neurath and Frank kept their focus on empirical significance. While they rarely discussed these matters explicitly, their writings give the impression that Neurath and Frank chose to adopt (if not retain) a contextual, exemplar-based approach to characterizing the criterion of meaninglessness and so decided to forego the enumeration of necessary and sufficient conditions. Mach’s precept cited earlier is an example of such a pragmatic approach, as is, it should be noted, Peirce’s criterion of significance, endorsed by Quine (1969), which claims that significance consists in making a discernible difference whether a proposition is likely to be true or false. Mach’s pragmatic approach had been championed already before verificationism proper by Neurath, Frank and Hahn who became, like Carnap, early opponents of conclusive verifiability. (Indeed, it is doubtful whether Neurath’s radical fallibilism, most clearly expressed already in 1913, ever wavered.) This pragmatic understanding found clear expression in Neurath’s adoption (1935a, 1938) of K. Reach’s formulation of metaphysical statements as “isolated” ones, as statements that do not derive from and hold no consequences for those statements that we do accept on the basis of empirical evidence or for logical reasons. (Hempel’s dismissal, in 1951, of this pragmatic indicator presupposes the desiderata of the formalist project.) Finally, there is Frank’s suggestion (1963), coupled with his longstanding advice to combine logical empiricism with pragmatism, that Carnap’s purely logical critique of metaphysics in (1932a) was bound to remain ineffective as long as the actual use of metaphysics remained unexamined. It would be worth investigating whether—if the critique of the alleged reductionist ambitions of their philosophy could also be deflected (see section 3.3 below)—the impetus of the anti-verificationist critique can be absorbed by those with a pragmatic approach to the demarcation against metaphysics. Much as with Quine’s Peirce, such a criterion rules out as without interest for epistemic activity all concepts and propositions whose truth or falsity make no appreciable difference to the sets of concepts and propositions we do accept already.