The Logic and Metaphysics Workshop will meet on December 1st from 2:00-4:00 in-person at the Graduate Center (Room 8203) for a talk by Melissa Fusco (Columbia).

Title: Do the chances update by conditionalization?

Abstract: In “Subjectivist’s Guide to Objective Chance”, David Lewis proposes a chance-credence norm he calls the “Principal Principle” (PP). Lewis also writes, in Sec. 11, that a later chance distribution comes from an earlier one by conditionalization. In this talk, I use an accuracy framework to explore temporalist alternatives to PP. Rather than concerning how an agent’s ur-priors defer to the ur-chances, these temporalist alternatives hold that a rational agent defers to the chances that are current for her. I then sketch how a non-conditionalizing update rule can maximize chance’s own expected accuracy over a language capable of expressing this temporalist norm. This update rule is based on Goldstein (2020)’s conditionalization-with-normalization. 

The Logic and Metaphysics Workshop will meet on November 3rd from 2:00-4:00 in-person at the Graduate Center (Room 8203) for a talk by Brad Armour-Garb (SUNY-Albany).

Title: A novel defense of legal gluts

Abstract: While Graham Priest is best known for taking dialetheia—true contradictions (that is, true statements whose negations are also true)—to emerge from the semantic paradoxes, he (1987/2006) has long maintained that the strongest case for dialetheism emerges from the possibility of legal gluts—dialetheia that incorporate some aspect of law. This contrasts with a point made by JC Beall—that the only dialetheia arise from the semantic paradoxes. Priest argues for the possibility of legal gluts, rather than arguing for their actuality, by relying on hypothetical cases and arguing for their plausibility. Beall disputes Priest’s argument for their possibility and argues that they are in fact impossible. In my talk, after setting out assumptions that serve as “common ground” for the current debate, and briefly summarizing arguments for and against their possibility, I show that Beall’s argument against Priest does not work. I then develop a novel argument for their possibility and, time permitting, go further than Priest by making a case for the actuality of legal gluts.

The Logic and Metaphysics Workshop will meet on November 17th from 2:00-4:00 in-person at the Graduate Center (Room 8203) for a talk by Giuliano Rosella (Turin).

Title: The probability and logical representation of suppositional conditionals

Abstract: We present new results concerning the probability and logical representation of suppositional conditionals—conditionals whose truth depends on the consequent holding in appropriately selected worlds where the antecedent is true (e.g., Stalnaker conditionals and Lewis counterfactuals). We show that the probability of such conditionals can be precisely captured by an updated Belief function within the framework of Dempster–Shafer Theory of Evidence (DST). A key consequence of this result is that the probability of suppositional conditionals is bounded by standard imaging-updated probabilities. This finding generalizes Lewis’s earlier characterization of Stalnaker conditionals in terms of Imaging and addresses an open problem concerning the characterization of the probability of counterfactuals. Our approach formally bridges DST with conditional logic and employs a logical reconstruction of Lewis’s counterfactuals as a form of necessitated Stalnaker conditionals, leveraging a notable correspondence between modal operators and Belief functions.

Note: This is joint work with Tommaso Flaminio (IIIA-CSIC, Barcelona), Lluis Godo (IIIA-CSIC, Barcelona), and Jan Sprenger (Turin).

The Logic and Metaphysics Workshop will meet on October 27th from 2:00-4:00 in-person at the Graduate Center (Room 8203) for a talk by Michael Della Rocca (Yale).

Title: Akrasia, explanation, and a rationalist Trojan horse

Abstract: In this talk, I will explore whether weakness of will or, as I think it is better called, akrasia is possible. I will argue that all accounts that accept the possibility of akrasia sever the link between evaluation of an action as best and one’s motivating desires. Such severing is, I will argue on largely rationalist grounds, unintelligible. I will then go out of my way to be generous: I will offer my opponent a powerful and seemingly promising response in the spirit of rationalism to my argument against the possibility of akrasia. However, this “gift” to my opponents surprisingly turns out to be something of a Trojan horse because, far from shoring up the possibility of akrasia, this response to my argument only threatens to cast into doubt or worse not only akrasia, but also the possibility of reasons for action in general and the coherence of the notion of normativity. The talk ends with some observations as to what this new understanding of action without reasons for action and without normativity might look like.

The Logic and Metaphysics Workshop will meet on November 10th from 2:00-4:00 in-person at the Graduate Center (Room 8203) for a talk by Yale Weiss (CUNY).

Title: Peripatetics, Stoics, and connexive implication

Abstract: Connexive logics form a heterodox family of systems characterized by contra-classical principles of conditionality and negation including so-called Aristotle’s and Boethius’ theses. In this talk, I introduce connexive logic and survey its origins. While McCall (1966) attributed connexivism to Peripatetic and Stoic logicians alike, and Lenzen (2022) argued against attributing it to several Peripatetic logicians, I argue that there is strong evidence for connexivism throughout the Peripatetic tradition but that Stoic logicians such as Chrysippus are unlikely to have embraced it. Along the way, I critically examine possible motivations for Peripatetic connexivism and note connections to more recent logical developments.

The Logic and Metaphysics Workshop will meet on October 20th from 2:00-4:00 in-person at the Graduate Center (Room 8203) for a talk by Eno Agolli (CUNY).

Title: All counterpossibles are false

Abstract: Counterpossibles are conditionals with impossible antecedents. All analyses of conditionals today agree that some counterpossibles are true. In this paper, I advance — to my knowledge for the first time — absurdism, the view that all counterpossibles are false. I do that in two steps. First, I show that there exists indeed an alternative analysis of conditionals which entails absurdism and which is well-motivated. The alternative analysis construes conditionals as plural definite descriptions of possible worlds and it is motivated by an impressively thoroughgoing parallelism between conditionals and definite plurals. Second, I show that absurdism itself is independently motivated, as it provides desirable logical results, a better rationale for positing pragmatic repair for counterpossibles, and ties in with a contemporary current of general skepticism toward counterfactuals.