LEM ─ Logic, Epistemology & Metaphysics Forum
Summer 2016 Programme
Jack Woods (Bilkent University, Ankara)
Title: Characterising Invariance
Abstract: Probably the most widespread way to give a precise characterization of the logical constants identifies them with terms whose extensions exhibit the formal property of invariance under some type of transformation such as permutation (Tarski 1986). This approach, dating back to (Tarski 1986) and (Mautner 1946), has a number of useful connections with definability (McGee 1996), and seems to capture at least one sense in which logical expressions are immune to the particular natures of the objects they are applied to. There have been, however, important criticisms, due to William Hanson and Timothy McCarthy, that suggest that invariance of extensions is insufficient for logicality since terms can have invariant extensions even if which extension it has depends on contingent facts. This implies, the argument goes, that logical truths can be contingent and that we cannot grasp the truth of logical truths a priori.
These arguments have recently been criticized by Gil Sagi (2015). While I agree with Sagi’s critique of the original arguments, I think that we can reformulate these arguments to argue that invariance of extension or even intension is insufficient for logical terms, in something more closely approximating natural language, because meaning in natural language is plausibly neither extensional nor intensional. I motivate a background framework for applying invariance criteria to terms of a fragment of natural language, show how to define both (isomorphism) invariance of content and (isomorphism) invariance of character, then argue, using analogues of Hanson and McCarthy's arguments, for a strengthened invariance criterion:
Double-Standard Invariance: An expression φ is logical only if both the content and the character of φ is invariant.
I close by demonstrating that (under certain plausible assumptions) both types of invariance, content and character, have nice connections to modal properties: sentences composed of content-invariant terms is shallowly necessary (true at every possible world), whereas sentences composed of character-invariant terms is deeply necessary (true no matter which world is actual).
John Morrison (Columbia University)
Title: Perceptual Structuralism: Objects, Kinds, and Qualities
Abstract: In a series of recent papers I motivated an approach to perceptual intentionality that I first called "anti-atomism" and now call "structuralism." In those papers I focused on color perception. My talk will expand that focus to object and kind perception. I will also explore structuralism’s implications for naturalism, the nature of consciousness, and the difference between perceiving and believing. My goal is to convince you that structuralism is a promising alternative to the approaches of Dretske, Millikan, and Fodor, among others.
Gil Sagi (Ludwig Maximilians University, Munich)
Title: Invariance Criteria: Terms and Constraints
Abstract: In the talk I shall briefly present my work on the framework of semantic constraints, and will show how invariance criteria for logical terms can be generalized so as to apply to semantic constraints. Logical consequence is viewed by many as depending on the distinction between logical and nonlogical terms. The new proposed logical framework does not lean on the distinction between logical and nonlogical terms. The framework, couched in model theory, is conservative with respect to the conventional view of logic as necessary and formal, and provides a conceptual wealth rising from a generalization of standard logic. A semantic constraint for L is a sentence in the metalanguage that somehow constrains or limits the admissible models for L (and can be viewed as a meaning rule). Logical terms (or more precisely, rules defining logical terms) are merely a special case of semantic constraints, while all the semantic constraints in a system are involved in determining logical consequence for L. I shall briefly present some definitions and results in the framework, and move on to discuss criteria for logicality.
In previous work I left open the question of whether there is a “correct” set of semantic constraints. Criteria for logical terms have been discussed extensively in the literature. Invariance criteria for logical terms have proved to be of special interest. I shall present a natural way of generalizing invariance criteria to apply to semantic constraints. This generalization has interesting consequences that also shed light on the criteria in their original formulation. Drawing on the consequences of the proposed generalization, I will suggest that the debate over logical terms diverts us from the more crucial issues of how meanings are captured in logical systems.
John Divers (University of Leeds)
Title: Quine on Modality: Towards a Synoptic, Charitable and Forward-Looking Account
Abstract: Quine’s skepticism about modality is indisputably a stance of the highest rank of importance in the history of analytic philosophy and, accordingly, it is our intellectual duty to come to terms with it. Here, I attempt to lay the ground for an approach to that project in which three basic elements are integrated.
(1) Firstly, the approach is synoptic so that we might appreciate to some extent what all of the significant elements of Quine’s modal skepticism are, and how they combine to make up the picture.
(2) Secondly, the approach is charitable, so that it is geared towards maximizing our understanding, and benefitting from the work of, one of the great thinkers in our tradition.
(3) Thirdly, the approach is not only retrospective but attempts orientation towards later, current and prospective attempts to solve the philosophical problems of modality.
Paniel Osberto Reyes Cárdenas (Autonomous University of Puebla State (UPAEP), Mexico)
Unless stated, talks begin at 5.30pm, in Room 243, 2nd floor, Senate House, Malet St., WC1.
If you would like to have dinner with the speaker after their talk, please email the LEM Convener, Corine Besson: email@example.com