Formal Philosophy

logic, mathematics, and philosophy

Bobzien: Higher-Order Vagueness

by Yang Liu

KRIPKE CENTER LECTURE
Kripke Semantics for Columnar Higher-Order Vagueness
Susanne Bobzien (Yale University)
Thursday, May 16, 4:15-6:15pm
Room 5307, GC

Abstract. Hierarchical higher-order vagueness leads to incoherence when it is used as a means to avoid a sharp boundary in the Sorites paradox (cf. Sainsbury 1990, Wright 1992, Shapiro 2006). The challenge is to provide a compositional notion of higher-order vagueness that (i) allows infinite higher orders, (ii) retains the desired relevance to the Sorites, (iii) allows for a model-theoretic representation that reflects such relevance, but (iv) does not run into any higher-order vagueness paradox. In some recent papers I have introduced the only type of higher-order vagueness that meets this challenge (“columnar higher-order vagueness”) and have set forth some of its elements. In this paper, I explain what columnar higher-order vagueness is, give a formalization of its core properties in terms of an axiomatic modal system, and produce a Kripke semantics for its simplest (i.e. bivalent & classical) form together with a philosophical interpretation of the semantics. I finish with an illustration of how the semantics can be used as an infrastructure for epistemicist and non-epistemicist bivalent theories of vagueness and briefly touch upon possible modifications for three-valued logics.

Tamar Lando: The topology of gunk

by Ignacio Ojea

NY PHILOSOPHICAL LOGIC GROUP
The topology of gunk
Tamar Lando (Columbia University)
Monday, May 13th, 4 to 6 PM
2nd floor seminar room, Philosophy Department, NYU (5 Washington Place).

Abstract. Space as we typically conceive of it in mathematics and physics is composed of dimensionless points. Over the years, however, some have denied that points, or point-sized parts are genuine parts of space. Space, on an alternative view, is ‘gunky’: every part of space has a strictly smaller subpart. If this thesis is true, how should we model space mathematically? The traditional answer to this question is most famously associated with A.N. Whitehead, who developed a mathematics of pointless geometry that Tarski later modeled in regular open algebras. More recently, however, Whiteheadian space has come under attack, because it does not allow us to talk about the size or measure of regions in a nice way. A newer approach to the mathematics of gunk, advanced by F. Arntzenius, J. Hawthorne, and J.S. Russell, models space via the Lebesgue measure algebra, or algebra of (Lebesgue) measurable subsets of Euclidean space modulo sets of measure zero. But problems arise on this approach when it comes to doing topology. According to Arntzenius, the standard topological distinction between ‘open’ and ‘closed’ regions “is exactly the kind of distinction that we do not believe exists if reality is pointless.” I argue that the turn to non-standard topology in the measure-theoretic setting rests on a mistake. Once this is pointed out, the newer approach to gunk can claim two important advantages: it allows the gunk lover to talk about size and topology—both in perfectly standard ways.

Gaifman: Epistemic and Ontological Problems Concerning Mathematics

by Yang Liu

HARVARD/MIT LOGIC SEMINAR
Epistemic and Ontological Problems Concerning Mathematics
Haim Gaifman (Columbia University)
Tuesday, April 30, 2013, at 4:15 PM
Fong Auditorium (Boylston Hall 110), Harvard University

Abstract. Philosophy of mathematics is confronted with two major questions: (i) How do we come to know mathematical propositions? (ii) What is the nature of mathematical truth? Attempts to give satisfactory answers to one of the questions have resulted in unsatisfactory accounts regarding the other. I shall outline an approach intended to do justice to both questions. This is an ongoing work.

Hamkins: The theory of infinite games, with examples, including infinite chess

by Yang Liu

YESHIVA MATH/PHIL CLUB
The theory of infinite games, with examples, including infinite chess
Joel David Hamkins (CUNY)
Tuesday, April 30, 2013 5:45 pm
Furst Hall, Amsterdam Ave. & 185th Street, Yeshiva University

Abstract. I will give a general introduction to the theory of infinite games, suitable for mathematicians and philosophers. What does it mean to play an infinitely long game? What does it mean to have a winning strategy for such a game? Is there any reason to think that every game should have a winning strategy for one player or another? Could there be a game, such that neither player has a way to force a win? Must every computable game have a computable winning strategy? I will present several game paradoxes and example infinitary games, including an infinitary version of the game of Nim, and several examples from infinite chess.

Hellman: On Resolving the Set-Theoretic and Semantic Paradoxes

by Ignacio Ojea

NY PHILOSOPHICAL LOGIC GROUP
On Resolving the Set-Theoretic and Semantic Paradoxes
Geoff Hellman (University of Minnesota)
4-6pm, Monday, April 22nd
2nd floor seminar room, NYU (5 Washington Place)

Abstract. Our main goals are, first, to describe how modal structuralism resolves the set-theoretic paradoxes, concentrating on the Burali-Forti paradox, and then to note a close connection to recent proposals (due to Cook and Schlenker, independently) for resolving semantic paradoxes, especially the Liar.

Suppes Lectures

by Yang Liu

An interdisciplinary program followed by a reception celebrating the academic contributions to psychology, philosophy, and neuroscience by

Patrick Suppes, Ph.D. ’50 GSAS
Lucie Stern Professor of Philosophy, Emeritus at Stanford University

Introduction

  • David Krantz (Psychology)
  • Patrick Suppes

Speakers

  • Christopher Peacocke (Philosophy)
  • Niall Bolger  (Psychology)
  • Mark Churchland (Neuroscience)

Thursday, May 2, 2013, 2 p.m. Program, 4:15 p.m. Reception at Faculty House, 64 Morningside Drive, Program in Seminar Room 1, 2nd floor, Reception in Presidential Room 1, 3rd floor. Please respond by Monday, April 29 to Amy Cole at 212-854-8450 or amy@psych.columbia.edu