Wim Vanrie

I defend an account of Moore's conception of Common Sense—as it figures in "A Defence of Common Sense"—according to which it is based in a vision of the community of human beings as bound and unified by a settled common understanding of the meaning of our words and statements. This, for Moore, is our inalienable starting point in philosophy. When Moore invokes Common Sense against idealist (and skeptical) philosophers, he is reminding them that they too are bound by this common understanding, which cannot just be left behind as they confusedly believe. On Moore's conception, Common Sense becomes nothing other than the affirmation that there is such a common understanding—that there is Common Sense—which yields a specific body of Common Sense knowledge. This yields a more principled account of Common Sense than a mere tallying of what contingently happens to be believed (or known) by all.

I investigate why Frege rejected the theory of types, as Russell presented it to him in their correspondence. Frege claims that it commits one to violations of the law of excluded middle, but this complaint seems to rest on a dogmatic refusal to take Russell’s proposal seriously on its own terms. What is at stake is not so much the truth of a law of logic, but the structure of the hierarchy of the logical categories, something Frege seems to neglect. To come to a better understanding of Frege’s response, I proceed to investigate his conception of the nature of the logical categories, and how it differs from Russell’s. I argue that, for Frege, our grasp of the logical categories cannot be severed from our grasp of the Begriffsschrift notation itself. Russell, on the other hand, attaches no such importance to notation. From Frege’s point of view, Russell has not succeeded in presenting an alternative conception of the logical hierarchy, since such a conception must go in tandem with the development of a notation. Moreover, Frege has good reasons to think that Russell’s proposal does not admit of a suitable notation.

I argue that no successful version of Williamson's anti‐luminosity‐argument has yet been presented, even if Srinivasan's further elaboration and defence is taken into account. There is a version invoking a coarse‐grained safety condition and one invoking a fine‐grained safety condition. A crucial step in the former version implicitly relies on the false premise that sufficient similarity is transitive. I show that some natural attempts to resolve this issue fail. Similar problems arise for the fine‐grained version. Moreover, I argue that Srinivasan's defence of the more contentious fine‐grained safety condition is also unsuccessful, again for similar reasons.

Frege's conception of the logical categories has vexed commentators for decades. In this dissertation, I argue that it revolves around two forms of internality. The first is the internality of its use in the expression of judgment to the sign. A proper understanding of that internality reveals how Frege's philosophical logic cannot be fit into the framework given by the contemporary syntax/semantics distinction. The second is the internality that obtains between the way in which Begriffsschrift signs stratify into different categories, on the one hand, and the way in which the realm of Bedeutungen stratifies into logical categories, on the other hand. A proper understanding of this internality reveals how Frege's conception of the relation between language and the world is neither a form of realism nor a form of linguistic idealism. To come to understand Frege's conception of the logical categories, is to come to understand both these forms of internality by coming to understand how they hang together.

This paper critically discusses Hacker’s reading of nonsense in Wittgenstein’s Tractatus in terms of his notion of misuse, which is taken to consist in the violation of rules of logical syntax. I argue that Hacker’s reading relies on an equivocation between sign and symbol: what is ‘misused’ is a mere sign, but the verdict of nonsensicality relies on seeing it as a symbol. Although Hacker seeks to distance himself from resolute readings – according to which nonsense always consists in nothing but a failure to assign meaning to one’s sentences – I argue that his own verdicts of nonsensicality have their ultimate grounds in exactly the same sort of assessment, i.e. whether meaning has been assigned to a sentence. The rules of logical syntax, contrary to his own intentions, do no real work in determining whether a sentence is nonsensical or not.

Many prominent arguments for epistemic relativism take their departure from the observation that a certain kind of epistemic symmetry is present in particular empirical cases. In this paper, we seek to attain further clarity about the kind of symmetry at issue, and the sort of relativism to which such symmetry can reasonably be taken to give rise. The need for such an investigation is made apparent, we believe, by the fact that prominent anti-relativist arguments such as that advanced by Boghossian in his influential book Fear of Knowledge (2006) yield distorted pictures of the matter. Following Boghossian, we present our argument through a detailed consideration of the dispute between Bellarmine and Galileo concerning heliocentrism. Contrary to what Boghossian claims, the relevant sort of symmetry does not concern a difference in fundamental epistemic principles between Bellarmine and Galileo, but rather a much more localized difference in procedures for adjudication between shared principles in the novel epistemic circumstances generated by Galileo's telescopic observations. Bellarmine and Galileo advance fundamentally different procedures of adjudication that are nevertheless equally rational. The upshot is not so much the denial that there are absolute epistemic facts as such, as Boghossian thinks, but rather the denial that there is an absolute fact of the matter as to which was the most rational way to proceed: Bellarmine's or Galileo's. What this gives us, is the denial that there is a certain kind of absolute epistemic fact.

In his 1939 Cambridge Lectures on the Foundations of Mathematics, Wittgenstein proclaims that he is not out to persuade anyone to change their opinions. I seek to further our understanding of this point by investigating an exchange between Wittgenstein and Turing on contradictions. In defending the claim that contradictory calculi are mathematically defective, Turing suggests that applying such a calculus would lead to disasters such as bridges falling down. In the ensuing discussion, it can seem as if Wittgenstein challenges Turing's claim that such disasters would occur. I argue that this is not what Wittgenstein is doing. Rather, he is scrutinizing the meaning and philosophical import of Turing's claim—showing how Turing is wavering between making an empirical prediction and a logical observation, and that it is only through this wavering that Turing can believe that he has provided a proper explanation of why contradictory calculi are mathematically defective.