A Carnapian Defence of Metaphysics

Darren Bradley (University of Leeds)

Abstract: One of the central ideas of logical positivism was that there is something wrong with metaphysical debates. Despite the rehabilitation of metaphysics in recent years, the worry that there is still something wrong with metaphysical debates has not gone away. Following Bennett (2009), we’ll call this loose idea dismissivism. Many dismissivists trace their view back to Carnap’s ‘Empiricism, Semantics and Ontology’ (1950a). But the reason Carnap takes a dismissive attitude to metaphysics is a matter of controversy. I will argue that no reason is given in ‘Empiricism, Semantics and Onotlogy’; and this is because his reason for rejecting metaphysical debates was given in ‘Pseudo-Problems in Philosophy’ (1928). The argument there assumes verificationism, which is why Carnap claims that there is no fact of the matter about the answer to metaphysical questions – any candidate answer would be meaningless. But I will argue that his argument survives the rejection of verificationism. The root of his argument is the claim that metaphysical statements cannot be justified; the point is epistemic, not semantic. I will then argue that what’s needed to answer Carnap’s challenge is a defence of a priori justification. And ironically enough, the locus classicus defending a priori justification is Carnap’s ‘Logical Foundations of Probability’ (1950b). Thus, the later (objective Bayesian) Carnap had a response to the earlier (anti-metaphysical) Carnap.