ABSTRACT
Logical positivism was to a large extent an offshoot of Wittgenstein’s Tractatus. As the Circle understood (and often misunderstood) that book, it demonstrated how ‘consistent empiricism’, as they put it, is possible. It did so by showing, so they thought, that truths of logic and mathematics are tautologies, hence ‘analytic’, true by convention or true in virtue of the meanings of the constituent logical terms, and hence that pure reason alone can arrive at no substantive truths about reality.1 From the Tractatus, members of the Circle derived their conception of the task of philosophy, namely the logicolinguistic analysis of ‘scientific propositions’, and the disclosing of pseudopropositions of ‘metaphysics’. The contribution of philosophy is not to human knowledge, but to the clarification by means of logical analysis of what is known. They accepted the thesis of extensionality, the analysability of all empirical propositions into basic propositions, and the conception of a language as a calculus of signs connected to reality by means of ‘concrete definitions’ (ostensive definitions) of the primitive terms. From discussions with Wittgenstein, transmitted to the Circle by Schlick and Waismann, they derived the principle of verification.
