 But such acceptance, much as in Neurath’s model, could be in principle revoked. It is a contingent fact that scientists will stop at easily testable statements simply because it will be easier to reach an agreement. It is important that basic statements satisfy explicit conditions of testability or else they could not be rightful part of science. Popper could offer no rational theory of their acceptance on pain of having to have recourse to theories of psychology of perception and thereby weakening his normative criterion of demarcation. In his view, his method, unlike Neurath’s, didn’t lead to either arbitrariness or dogmatism or the abandonment of empiricism. As he had argued against Spengler in 1921, historical contingency provides the rich constraints that establish communities and communication and the possibility of knowledge and, in this holistic form, preclude radical relativism in practice; in historically situated practice, inherited or constructed stable Archimedean points always come into place; there is no tabula rasa (Neurath 1921/1973). Neurath rejected Popper’s approach for its stealth empiricism and its pseudorationalism: its misplaced emphasis on and faith in the normative uniqueness, precision and conclusiveness of a logical method—at the expense of its own limitations and pragmatic character (Zolo 1989, Cat 1995, Hacohen 2000).