33 Neopositivism, realism, and the status of philosophy Mario Alai 1. Neopostivism During the 1920’s and early 1930’s the neopositivists thought that (NP1) all statements could be sharply distinguished into analytic and synthetic. Analytic statements were cognitively empty but meaningful (in fact, necessarily true by the rules of language), and constituted the formal sciences (logics and mathematics), through which moreover they played an indirect role also in the empirical sciences. In turn, (NP2) all synthetic statements could be sharply divided into those which were (directly or indirectly) verifiable, and those which were not. (NP3) Verifiable statements constituted the main body of empirical sciences, and the only form of genuine knowledge. Unverifiable statements, as taught by Kant, were not genuine knowledge, and constituted all kinds of non-scientific discourse, especially metaphysics. Moreover, they held that (NP4) the whole cognitive meaning, or content, of a statement consisted just in the set of possible experiences 1 which would verify it. In equivalent words, meaning was the method of verification: any empirical proposition was only about the presence or the regular connection of certain experiences (Schlick 1932a, pp. 100, 107, 111, etc.), and everything else was meaningless. Therefore the neopositivists maintained that 1. “Possible” in the sense of at least conceivable (Carnap 1928b § 7, Schlick 1932a, p. 89) or in principle, or logically possible (Schlick 1932a, pp. 88-89; 1936: see § 2 below). Some of them preferred to consider experiences as consisting of sensations (“sense data”), others as perceptions of physical objects; but they agreed that this decision was mainly a pragmatic one.