NEOPOSITIVISM. – Neopositivism, also called logical positivism, formally dates its beginning to the foundation of the Wienerkreis (Vienna Circle), which took place in 1928 within the E. Mach Society, already existing in that city. The principal aim of neopositivism is the one positivism (v.), namely, to provide a secure foundation for the sciences and to metaphysics (v.); and this commonality of purpose may be said to be almost the only link between neopositivism and the classical positivism of Comte and his nineteenth-century successors. Its essential characteristic, however, lies in the exclusive use of logical analysis to demonstrate positivist theses.
Neopositivism is therefore a synthesis of empiricism, derived especially from Hume and Mach, and that current of formal logic or logistic which, beginning with Leibniz and passing through Boole and De Morgan, was constituted especially through the work of Pierce, Frege, Peano, Russell, and the Polish school. Nevertheless, the title of father of neopositivism belongs to Ludwig Wittgenstein, whose Tractatus logico-philosophicus (London 1922) still remains the fundamental work, through which it is possible to explain the various themes of the school as well as its various conflicting positions. Neopositivism rapidly spread from Austria to Germany and the United States and, to varying degrees, also to France, England, and Italy; and the principal reason for its success lies in the fact that neopositivism presents itself as the official philosophy of the new physics and as the philosophical interpretation of the thought of Einstein and Heisenberg. The principal founders of the Vienna Circle were Moritz Schlick, Rudolf Carnap, Hans Reichenbach, and Otto Neurath. Following the anti-Jewish persecutions in Germany and the annexation of Austria, many of these philosophers moved to America, gathering in the Chicago school together with local figures, including John Dewey, Charles W. Morris, Julius R. Weinberg, etc. In Italy, Peano, Pieri, and Vailati are considered precursors of neopositivism; Federigo Enriques represented a related tendency; among its followers or admirers were Ludovico Geymonat, the Centro di studi metodologici of Turin (N. Abbagnano, P. Buzzano, E. Frola), and the Centro di metodologia e analisi del linguaggio of Milan (S. Ceccato, V. Somenzi, G. Vaccarino).
The fundamental principle of neopositivism consists in assuming as a universal categorical principle what is a methodological principle of modern physics: the meaning of every proposition is the method of its verification; in other words, the only questions that make sense are those in which the result of one or more experiments is sought that can, at least conceptually, be carried out. In other terms, the only propositions that have meaning are those that can be entirely translated into physical language; and this led Neurath to designate neopositivist theory by the term Fisicalismo (Physikalismus, in Scientia, 50 [1931], pp. 297–303). For neopositivism, this empiricist principle must be joined to the possibility of logic, which is understood in a purely nominalist sense, as a set of propositions concerning the form of discourse and the rules for transforming one proposition into another having an identical meaning. All logical propositions are therefore tautological, and from this derive their necessity and universality; their sole task is to facilitate the recognition of tautologies when reasoning is complicated. For Wittgenstein, indeed, consistently with the fundamental empiricist principle, propositions of
logic express no meaning whatsoever; they are an important nonsense (Weinberg). This constitutes a serious difficulty for neopositivism, since a logic that cannot be expressed is a contradiction in terms; Carnap overcame this difficulty by distinguishing between two languages: syntactic language and object language. Carnap’s logical syntax provided the impetus toward the purest linguistic formalism of logic and of science itself.
On these foundations, neopositivism claims to eliminate metaphysics through the logical analysis of meaningful discourse. For if meaningful assertions are limited to what is empirically verifiable, and if all logical demonstrations and operations are reduced to tautological transformations, it follows that every metaphysical utterance, which by definition is a non-empirical proposition, is a pseudo-proposition devoid of meaning. Metaphysics is neither an error nor an illusion, but simply nonsense. On the same foundation rests the theory of scientific method, in which particular attention is devoted to natural laws, which, because of their universality, lack direct empirical meaning. For Wittgenstein, they are incomplete propositions devoid of meaning, and must be understood solely as prescriptive rules for the formation of singular empirical propositions concerning the future; for Carnap, by contrast, they are universal propositions endowed with meaning, insofar as they express the class of all particular propositions that follow from them; for both, however, they can never have an absolute value, but only a probabilistic and provisional one.
All these theories face an objection that did not escape their own authors: namely, the difficulty, or even impossibility, of constructing solely in terms of possible experience an intersubjective and objective world, such as the world that is the object of physical science. Within my personal experience, which is the only experience possible for me, it makes no sense to speak of the experiences of others, of other subjects, or of communication among individuals. One thus falls into linguistic solipsism, from which it is impossible to emerge either through the empiricist principle alone or through the pure logical syntax of language. Neopositivism’s effort is to overcome this difficulty by carrying the formalism of language still further, to the point of excluding from it any mention not only of facts and data but also of experience. According to Neurath, even protocol language (expressing the direct report of an individual’s personal experience) must from the outset have an impersonal and formal character, without extralinguistic reference. The problem of solipsism is thereby radically eliminated, it is true; not, however, in the sense of intersubjectivity and objectivity, but in that of pure impersonalism and nominalism, together with absolute conventionalism. Indeed, even for protocol propositions the criterion of truth fundamental to all positivism—that is, the positive fact independent of the researcher—is abandoned; and propositions are no longer judged except according to the internal coherence of the language. Thus logical positivism, or neopositivism, proves self-contradictory: for either it accepts the purely empirical meaning of propositions, and then empties logic of all meaning; or it confines itself to the formalism of pure logic, and then loses all contact with the absolute reality of the objective datum (v. METODOLOGIA).
there 1945; id., Fondamenti logici della scienza, there 1947; J. R. Weinberg, Introduzione al positivismo logico, Italian translation by L. Geymonat, Turin 1950. For a critique from the standpoint of Catholic philosophy: P. Hoenen, De principio fundamentali neopositivismi, in Acta II Congr. them., Rome 1937, pp. 367–74; L. Pelloux, La scuola neopositivistica di Vienna, in Riv. di filos. neos., 28 (1936), pp. 217–26; F. Selvaggi, Il n. e il metodo della nuova scienza, in Cin. Catt., 1947, II, pp. 501–13; id., Introduzione al positivismo logico, ibid., 1951, II, pp. 626–36.