Abstract

This article discusses the relationship between Ludwig Wittgenstein’s and Rudolf Carnap’s philosophies of logic during the time of Wittgenstein’s interactions with the Vienna Circle and up to 1934 when the German edition of Carnap’s _The Logical Syntax of Language_ was published. Whilst Section 1 focuses on the relationship between Carnap and Wittgenstein’s _Tractatus_, including Wittgenstein’s accusation of plagiarism against Carnap in 1932, Section 2 discusses the relationship between Carnap’s principle of tolerance and Wittgenstein’s similar principle of the arbitrariness of grammar. I argue that, although Carnap’s claim in _Logical Syntax_ to ‘go beyond’ Wittgenstein has certain justification in relation to the _Tractatus_, so does Wittgenstein’s priority claim. The relationship between Carnap’s philosophy of logic and the _Tractatus_ is thus more complicated than is often recognized. If the reference point is Wittgenstein in the early 1930s, however, Carnap cannot be described as going beyond him, and by 1934, Wittgenstein had advanced further than Carnap would ever venture. Despite evidence that Carnap knew about Wittgenstein’s principle of the arbitrariness of syntax well before his first articulations of his principle of tolerance, the extent of the influence of Wittgenstein’s principle on Carnap remains unclear. What can be established with certainty is that Wittgenstein’s principle predates Carnap’s and that Carnap resisted acknowledging him despite being urged to do so. Arguably, Wittgenstein’s account of syntax as both arbitrary and non-arbitrary is also superior in clarity to Carnap’s misleading claim about a ‘complete freedom’ implied by the principle of tolerance, because such a freedom only exists for idle syntactical systems that are not put to work. In Section 3, I discuss the relationship between Carnap’s notion of expediency and Wittgenstein’s account of the correctness or truth of logical accounts. As my discussion of Wittgenstein’s account brings out, Carnap’s rejection of truth in logic for expediency as the goal of logical clarifications does not follow from the principle of tolerance and is not justified by it. It remains unclear what justifies Carnap’s rejection of truth as the goal of logical clarification. Again, Wittgenstein’s account seems preferable, given the vacuity of the claim that expediency constitutes the basis of choice between different logical languages and clarifications.