Abstracts

An Introduction to Deep Fried Logic

Logic is Contractionless and Relevant, but Logic is (Accidentally) Contractionless and Relevant: An Introduction to Deep Fried Logic

Shay Logan

Logic, according to Beall, is the universal entailment relation. I claim that this forces us to accept that logic is contractionless and relevant. But neither relevance nor contraction-freedom, important as these features have been in the literature on logic and its philosophy, play a role in my argument. Instead, they are emergent features — logical accidents, if you will. Along the way I will familiarize us with a novel (and delicious) semantic theory that I call deep fried semantics.

How to compute with an infinite time Turing machine?

Sabrina Ouazzani

In this talk, we present infinite time Turing machines (ITTM), from the original definition of the model to some new infinite time algorithms.

We will present algorithmic techniques that allow to highlight some properties of the ITTM-computable ordinals. In particular, we will study gaps in ordinal computation times, that is to say, ordinal times at which no infinite time program halts.

Residuals and Conjugates in Positive Substructural Logics

Andrew Tedder

While the relations between an operation and its residuals play an essential role in substructural logic, a closely related relation between operations is that of conjugation — so closely related that with Boolean negation, the conjugates and residuals of an operation are interdefinable. In this talk extensions of Positive Non-Associative Lambek Calculus including conjugates (and residuals) of fusion are investigated. Some interesting properties of the conjugates are discussed, a proof system is presented, its adequacy questioned, and some further logics with conjugated operations are pondered.

Routley-Meyer relational semantics for some variants of Bradys´s 4-valued matrix

Sanda María López Velasco

On the one hand, the well-known logic BN4 was defined by R.T. Brady in 1982 and can be considered as the 4-valued logic of the relevant conditional. On the other hand, Routley-Meyer type ternary relational semantics is the semantics introduced by these authors in order to model the logic of relevance. Part of my current research involves applying a R-M semantics to different logics built upon some variants of MBN4 (the matrix of BN4) which verify the Routley and Meyer basic logic B.

The aim of this talk is to display these logics briefly and the reason why they could be of some interest. I will also explain how a R-M semantics can be applied to them.  Considering this, I will provide a general outline of the soundness and completeness theorems, valid for all these logics, and focus on the (corresponding) postulates proofs, which on the contrary need to be specified in each of these logics.

The pragmatics of truth-value judgments

Gregory Scontras

Investigations of linguistic meaning crucially rely on truth-value judgments: whether a sentence can truthfully describe a given scenario. On the basis of such judgments, researchers have concluded that young children perform quite differently from adults when it comes to understanding ambiguous utterances with multiple potential meanings. For example, when adults hear “Every horse didn’t jump over the fence,” they entertain two interpretations: either none of the horses jumped or not all of the horses jumped. Children usually only endorse the “none” interpretation, rejecting the utterance in a scenario where only two out of three horses jumped. However, subtle changes to the truth-value judgment task setup make children more adult-like. I summarize key results from the literature on child ambiguity resolution, noting three core variables that affect children’s disambiguation behavior. One of these variables concerns children’s processing ability: how easy it is to access the different grammatical interpretations. The other two variables concern children’s ability to manage the pragmatic context: understanding what the topic of conversation is, and modulating expectations about the world being described. I also highlight the nature of the truth-value judgment task children are being asked to engage in, which I then formally articulate using a cognitive computational model that specifies the role of each of these three variables in providing truth-value judgments. The results suggest that pragmatic factors play a larger role than processing factors in explaining children’s non-adult-like ambiguity resolution behavior, and the computational modeling framework allows us to understand exactly why that’s so. Indeed, by modeling the task itself, we see that the truth-value judgment data typically used to demonstrate children’s difficulty with ambiguity in fact require no disambiguation at all — just the ability to manage the pragmatics of the task.

Character assassination: de se semantics for indexicals

Craige Roberts

Claim: Both the directly referential semantics and the more recent anaphoric accounts of 1st and 2nd person indexicals offer a picture of indexicality which is empirically and conceptually inadequate. They fail to capture this fact: Indexicals are essentially perspectival, as reflected in the fact that 1st and 2nd person indexicals are always de se.

Why hasn’t that been evident before?

Here is something important that compositional semantics has taught us: You cannot properly assess the meaning of an expression without considering its use and meaning in embedded contexts. But, as Kaplan drove home, the English 1st and 2nd person pronouns never seem to vary in interpretation in embedded contexts. However, recent work in linguistics has uncovered a wide variety of unrelated languages where the 1st and 2nd person pronouns can be shifted under attitudes. Careful consideration of their shifted meanings offers a new perspective on indexicality. Accordingly, I offer arguments for a de se account of indexicality.

Ultraproducts and saturation

Reed Solomon

This talk will be an introduction to the ultraproduct construction and the model theoretic notion of saturation, which are two of the themes in Maryanthe Malliaris’s Annual Logic Lecture next week. My goal is to introduce these concepts with some examples and motivation to give anyone interested some familiarity with the key characters in Maryanthe’s story before she arrives. Maryanthe will define these concepts in her talk and will not presuppose any material from my talk.

The Strict-Tolerant Interpretation of the Weak Kleene Matrices

Thomas Ferguson

The framework of strict-tolerant consequence championed by Cobreros, Egré, Ripley and van Rooij provides a novel setting that permits one to have a transparent truth predicate without abandoning classical logic. The semantics for this notion of consequence, due to van Rooij, employs the three-valued strong Kleene matrices. A second framework that has received renewed attention is the collection of weak Kleene matrices, which have frequently appeared in the context of so-called logics of nonsense, making the pairing of these topics a natural avenue for investigation. In this talk, I’ll discuss strict-tolerant consequence on the weak Kleene matrices, its corresponding proof theory, and its interpretation. I’ll also discuss how the resulting notion of consequence bears on several matters in philosophical logic, including the content-theoretic interpretation of bounds consequence, the semantic properties of paradoxical sentences in the Principia Mathematica, and debates concerning the logical analysis of category mistakes.