Lewis's notion of a "natural" property has proved divisive: some have taken to the notion with enthusiasm, while others have been sceptical. However, it is far from obvious what the enthusiasts and the sceptics are disagreeing about. This paper attempts to articulate what is at stake in this debate.

Philosophical Investigations, Volume 45, Issue 2, Page 107-129, April 2022.

What is the source of logical and mathematical truth? This book revitalizes conventionalism as an answer to this question. Conventionalism takes logical and mathematical truth to have their source in linguistic conventions. This was an extremely popular view in the early 20th century, but it was never worked out in detail and is now almost universally rejected in mainstream philosophical circles. Shadows of Syntax is the first book-length treatment and defense of a combined conventionalist theory of logic and mathematics. It (...) argues that our conventions, in the form of syntactic rules of language use, are perfectly suited to explain the truth, necessity, and a priority of logical and mathematical claims, as well as our logical and mathematical knowledge. (shrink)

Is the world internally connected by a web of necessary connections or is everything loose and independent? Followers of David Hume accept the latter by upholding Hume’s Dictum, according to which there are no necessary connections between distinct existences. Roughly put, anything can coexist with anything else, and anything can fail to coexist with anything else. Hume put it like this: “There is no object which implies the existence of any other if we consider these objects in themselves.” Since Hume’s (...) day, Hume’s Dictum has played a major role in philosophy, especially in contemporary metaphysics. In ruling out necessary connections, Hume’s Dictum implies that causal relations and the laws of nature are contingent. It makes other demands on our metaphysics of science as well; for example, it places restrictions on our metaphysics of counterfactuals, dispositions, and explanation. The principle has applications in other areas too. Hume’s Dictum places constraints on our theories of abstract objects and moral properties. For example, Hume’s Dictum rules out the view that moral properties are distinct from, but necessarily connected to, non-moral properties. While Hume’s Dictum is a prominent principle in metaphysics, few Humeans have defended the principle at length. It is assumed more often than it is argued for. As a result, Hume’s Dictum no longer enjoys the reputation it once did. It’s common to hear complaints about the lack of arguments in support of Hume’s Dictum. Moreover, philosophers are increasingly willing to defend views that are at odds with Hume’s Dictum. A striking example of this is the recent explosion of interest in views that take causal relations and the laws of nature to be necessary. Humeans can no longer afford to be complacent. An extended defense of Hume’s Dictum is called for, and that’s what this dissertation aims to offer. This dissertation has three parts. In the first part, I lay out some preliminaries and offer a precise formulation of Hume’s Dictum. In the second part, I develop three arguments in favor of Hume’s Dictum. In the final part, I defend Hume’s Dictum against objections. (shrink)

Review of Causation and Free Will by Carolina Sartorio, Oxford University Press, 2016. viii + 188 pp. £35.00.

Statements of degree appear to falsify basic doctrines in Tractatus Logico-Philosophicus. I offer a fresh formulation of the challenge and assess a solution proposed on Wittgenstein’s behalf by Sarah Moss. I find that Moss’s proposal fails. The proposal rides in part on novel interpretations of pronouncements by Wittgenstein on the nature of the elementary proposition. I find that the interpretations cannot be sustained but that Moss’s textual case hints at important and overlooked features of the Tractarian program. I develop Wittgenstein’s (...) comparison of propositions to measuring instruments and apply it throughout, showing that it captures philosophical commitments in Tractatus that otherwise tend to slip from view. (shrink)

This is a review of 'The Facts in Logical Space' by Jason Turner.

Wittgenstein’s atomist picture, as embodied in his Tractatus, is initially very appealing. However, it faces the famous colour-exclusion problem. In this paper, I shall explain when the atomist picture can be defended in the face of that problem; and, in the light of this, why the atomist picture should be rejected. I outline the atomist picture in Section 1. In Section 2, I present a very simple necessary and sufficient condition for the tenability of the atomist picture. The condition is: (...) logical space is a power of two. In Sections 3 and 4, I outline the colour-exclusion problem, and then show how the cardinality-condition supplies a response to exclusion problems. In Section 5, I explain how this amounts to a distillation of a proposal due to Moss, which goes back to Carruthers. And in Section 6, I show how all this vindicates Wittgenstein’s ultimate rejection of the atomist picture. The brief reason is that we have no guarantee that there are any solutions to a given exclusion problem but, if there are any, then there are far too many. (shrink)

It is widely believed that some a priori necessary truths are not analytic in the sense of transformable by substitution of synonyms into logical truths. One much-cited example comes from the supposed incompatibility between colour predicates. The idea is that sentences like “Nothing is both blue all over (or uniformly or at a point) and also red” are not transformable into a logical truth in the same way as “Nothing is both a bachelor and married” because the requisite conceptual link (...) between “bachelor” and “not married” is absent between “blue” and “not red”. This paper examines whether colour exclusion may be more like the bachelor case than it initially appears. It transpires that the most promising line of thought is not, however, as has been argued at length in the literature, that “blue” in some more or less convoluted way manages to mean “not red”. Instead it is suggested that the requisite conceptual link may reside in the oft-ignored qualifications (“all over”, “uniformly”, etc.), without which there is no incompatibility in the first place. (shrink)

After Tractatus Logico-Philosophicus, Wittgenstein realized that elementary propositions may logically conflict with each other, due to the fact that the most elementary measurements may contradict each other. This led to the view that logic consists of various calculi. A calculus consists of measurement scales, each scale being a rule for the application of numbers. These scales determine logical relationships between elementary propositions by reason of arithmetical relations. Attempts to reject Wittgenstein's change in viewpoint, which ignore the relevance of measurement and (...) arithmetic, are remiss. In this light, I discuss Sarah Moss’s criticism of intermediate Wittgenstein. (shrink)

Wittgenstein introduced his claim about colour incompatibility originally in the Tractatus Logico-Philosophicus , where he stated that there could be only one colour in one place and time. It is commonly believed that Wittgenstein abandoned his conception of logical atomism when he realized the consequences of this claim. The aim of this article is to provide an interpretation of the colour incompatibility claim in terms of Wittgenstein’s phenomenology. I will focus on two works of great significance for the claim: Some (...) Remarks on Logical Form and Philosophical Remarks . These two works were written between 1929 and 1930, which is the beginning of the “middle period” in Wittgenstein’s philosophy. I will focus not only on Wittgenstein’s formulation of the colour incompatibility claim, but also on how this claim was justified. The explanation of Wittgenstein’s justification of this claim will help to understand his phenomenology and theory of philosophical grammar. (shrink)

Em linguística gerativa, distinguem-se várias propriedades formais dos sistemas representacionais: a infinidade discreta, a finitude discreta e a infinidade do contínuo. Não é frequente filósofos aplicarem essas distinções ao estudo da forma lógica. O fato de essas distinções serem raramente aplicadas resultou em os filósofos pressuporem, geralmente sem discutir, que todas as formas lógicas apresentam una infinidade discreta, como o faz a linguagem natural. Este artigo defende a existência de outros tipos de forma lógica, além daquela que apresenta infinidade discreta. (...) Na representação mental é possível encontrar formar apresentando infinidade contínua e finitude discreta, além da infinidade discreta. Além disso, tais representações mantêm relações lógicas entre si, parcialmente em virtude dessas formas. Isso equivale à alegação de que o estudo da lógica natural precisa ir além da faculdade de linguagem, abrangendo formas lógicas pertinentes a representações mentais que não se assemelham a sentenças. Isso incluiria formas lógicas pictóricas. O ponto final é que, no estudo da lógica natural, é preciso considerar as formas lógicas representadas a sistemas mentais que antecedem a evolução da linguagem. (shrink)