LEM Forum Autumn Programme 2016
LEM ─ Logic, Epistemology & Metaphysics Forum
Autumn 2016 Programme
Anna Mahtani (LSE)
Title: Arguments for Probabilism
Abstract: I examine both dutch book arguments and accuracy arguments for probabilism. On a natural interpretation of these arguments, they invoke the idea of truth across possible worlds. I argue that on this natural interpretation of the arguments, they are better described as arguments for something analogous to the metaphysical necessity of the probability axioms, rather than for the claim that conforming to the probability axioms is rationally required. I suggest alternative ways of reading these arguments, and under each reading I clarify what conclusions we should draw from the arguments. We are left with no argument for probabilism itself, which I argue is as it should be.
Julien Dutant (KCL)
Title: Safety logics for derived knowledge
Abstract: Derived knowledge is knowledge based on other knowledge: I may know that my colleague has left their office and, on that basis, know that they are at the pub. This talk investigates derived knowledge from the standpoint of a safety theory of knowledge. The central idea is to extend safety to argumentative attitudes, where argumentative attitudes relate us to arguments (sets of premises with a conclusion) like propositional attitudes relate us to propositions. The idea is straightforwardly formalized. The result is a new type of epistemic logic that sheds new light on logical omniscience, inductive knowledge and epistemic closure.
William Dunaway (Oxford)
Title: Epistemological Motivations for Anti-Realism
Abstract: Anti-realists often motivate their view by claiming that it has certain epistemological advantages over realism. For instance anti-realists in ethics sometimes claim that if realism is true, then we can’t know any substantive ethical claims. Moreover, they add, anti-realism explains why we can know these facts. I wish to examine the second part of this argument: the alleged epistemological benefits of anti-realism. I begin by outlining anti-realism as a metaphysical thesis, about what metaphysically grounds (for instance) the ethical facts. I sketch why it is tempting to think that this metaphysical thesis will carry substantial epistemological benefits. But I argue that this metaphysical thesis actually fails to explain why basic and relatively uncontroversial conditions on knowledge are met. I conclude by sketching what I take the source of this failure to be: anti-realists need to idealize their views in order to make them plausible on logical, metaphysical, and other grounds. These idealizations, while necessary, deprive their view of the resources it needs in order to have distinctive epistemological consequences.
Salvatore Florio (Birmingham)
Title: Salvatore Florio (Birmingham)
Abstract: A prominent objection against the logicality of second-order logic is the so-called Overgeneration Argument. However, it is far from clear how this argument is to be understood. In the first part of the talk, we examine the argument and locate its main source, namely the alleged entanglement of second-order logic and mathematics. We then identify various reasons why the entanglement may be thought to be problematic. In the second part of the talk, we take a metatheoretic perspective on the matter. We prove a number of results establishing that the entanglement is sensitive to the kind of semantics used for second-order logic. These results provide evidence that, by moving from the standard set-theoretic semantics for second-order logic to a semantics that makes use of higher-order resources, the entanglement either disappears or may no longer be in conflict with the logicality of second-order logic.