Cathy Legg

This paper offers an expressivist account of logical form, arguing that in order to fully understand it one must examine what valid arguments make us do (or: what Achilles does and the Tortoise doesn’t, in Carroll’s famed fable). It introduces Charles Peirce’s distinction between symbols, indices and icons as three different kinds of signification whereby the sign picks out its object by learned convention, by unmediated indication, and by resemblance respectively. It is then argued that logical form is represented by the third, iconic, kind of sign. It is noted that icons uniquely enjoy partial identity between sign and object, and argued that this holds the key to Carroll’s puzzle. Finally, from this examination of sign-types metaphysical morals are drawn: that the traditional foes metaphysical realism and conventionalism constitute a false dichotomy, and that reality contains intriguingly inference-binding structures.

This substantial book is a highly original and thorough work of synthetic first philosophy. Although it has some recognizable roots in the Kantian/Sellarsian tradition of the Pittsburgh school, it adds a wealth of precise discussion of examples from science and mathematics, made possible by Macbeth's dual training in arts and sciences. It presents a developmental story of human reason bootstrapping itself towards greater power and clarity through the Western tradition (which is the sole purview of the discussion). This development is divided into three distinct stages, which might be summarized very roughly as knowledge of: i) Objects, ii) Concepts applied to Objects and iii) Concepts alone.

Wittgenstein's discussion of rule-following is widely regarded to have identified what Kripke called "the most radical and original sceptical problem that philosophy has seen to date". But does it? This paper examines the problem in the light of Charles Peirce's distinctive "scientific hierarchy". Peirce identifies a phenomenological inquiry which is prior to both logic and metaphysics, whose role is to identify the most fundamental philosophical categories. His third category, particularly salient in this context, pertains to general predication. Rule-following scepticism, the paper suggests, results from running together two questions: "How is it that I can project rules?", and, "What is it for a given usage of a rule to be right?". In Peircean terms the former question, concerning the irreducibility of general predication (to singular reference), must be answered in phenomenology, while the latter, concerning the difference between true and false predication, is answered in logic. A failure to appreciate this distinction, it is argued, has led philosophers to focus exclusively on Wittgenstein's famous public account of rule-following rightness, thus overlooking a private, phenomenological dimension to Wittgenstein's remarks on following a rule which gives the lie to Kripke's reading of him as a sceptic