Scenes from the ‘A farewell to Graham Priest’ event held on May 18, 2026.

The Logic and Metaphysics Workshop will meet on May 18th from 2:00-4:00 in-person at the Graduate Center (Room 9205) for a special farewell event for Graham Priest (CUNY). Reflections on Priest’s work will be given by Bradley Armour-Garb (Albany), Hartry Field (NYU), Achille Varzi (Columbia), and Yale Weiss (CUNY).

The Logic and Metaphysics Workshop will meet on May 11th from 2:00-4:00 in-person at the Graduate Center (Room 9205) for a talk by Mircea Dumitru (Bucharest).

Title: On the Normativity of Logic and Ethics

Abstract: The talk focuses on the normativity of logic, and how this relates to debates about logical exceptionalism and anti-exceptionalism, by comparing logical and ethical normativity within the broader landscape of modal concepts. I distinguish three irreducible kinds of necessity: metaphysical necessity – grounded in the nature of reality; natural necessity – grounded in laws of nature; normative necessity – grounded in norms, obligations, or what ought to be. The presentation surveys the philosophical debate about the normativity and methodology of logic: (i) logic’s traditional exceptional status rests on its normative authority and universality; (ii) anti-exceptionalists, by contrast, treat logical theory formation as fallible, abductive, and revisable, aligned with scientific practice; (iii) the contemporary challenge is to reconcile logic’s normative role with a non-exceptionalist, abductive methodology—a question I tackle from an exceptionalist standpoint. I side (with some reservations) with Exceptionalism in both logic and ethics, aligning with Derek Parfit’s objectivist view of morality and endorsing the robustness and irreducible character of normative necessity.

The Logic and Metaphysics Workshop will meet on May 4th from 2:00-4:00 in-person at the Graduate Center (Room 9205) for a talk by Marian Călborean (Bucharest).

Title: The minimal ontology of time: A unified axiomatization for A- and B-theories

Abstract: How little ontology is needed to accommodate the major logical and metaphysical theories of time? I present a first-order framework whose primitive structure consists of moments, events, a temporal order, start and end functions, tense traces, and minimal change and reality flags. Optional geometric schemas are available for Newtonian, branching, relativistic, and fragmentary time. I argue that the axioms are independently motivated and systematically variable and that canonical positions in temporal metaphysics (presentism, growing-block theory, moving-spotlight theory, eternalism, and fragmentalism) can be recovered as parameter settings or schema extensions of the neutral core. I then prove a representation theorem for Prior’s PF and indicate extensions to metric and interval temporal logics. The framework thereby compares the metaphysical costs of temporal ontologies. Conditional on preserving global reality and substantial temporal passage, growing-block theory emerges as the most parsimonious A-theoretic ontology, while Fine-style fragmentalism divides into two non-equivalent variants, depending on whether fragments are understood as tense-coherent histories or as spacetime regions.

The Logic and Metaphysics Workshop will meet on April 27th from 2:00-4:00 in-person at the Graduate Center (Room 9205) for a talk by Mel Fitting (CUNY).

Title: A few intuitionist logics

Abstract: Intuitionistic logic was designed in the 1930’s by Heyting to embody the reasoning of a constructivist mathematician.  In the 1960’s Kripke introduced possible world semantics for it, capturing ideas embodied in intuitionistic reasoning, though it requires classical mathematics to show that it works.  A constructivist doesn’t reason only about mathematics.  The real world is of some interest too.  But there may be gaps in our knowledge, or contradictory information, gluts.  There are relatives of classical logic aimed at this: logic of paradox LP, for gluts; Kleene’s strong three-valued logic K3, for gaps, first-degree entailment FDE, for both.  These don’t take constructivist motivations into account, but there are intuitionistic analogs that do; we call them ILP, IK3, and IFDE.  These are what I will discuss.  These have a Kripke-style semantics, natural tableau proof systems, and share many fundamental properties of Heyting’s calculus.  But much is still unknown, and this is all rather new.  This work has appeared in Notre Dame Journal of Formal Logic, Simple tableaus for simple logics last year and Simple tableaus for simple intuitionistic logics this year.

The Logic and Metaphysics Workshop will meet on April 20th from 2:00-4:00 in-person at the Graduate Center (Room 9205) for a talk by Jacopo Giraldo (Padua).

Title: The Grounding Structure of Location

Abstract: How is the location of a material object metaphysically determined? Is it where it is because of its parts or the bigger wholes it is part of? In this essay, we open an inquiry into this problem by introducing and contrasting two radical principles. The Bottom-Up Grounding-Locative (BUGL) principle holds that the location of a composite object is grounded by the locations of its components and mereological relations between objects and spatiotemporal regions. In contrast, the Top-Down Grounding-Locative (TDGL) principle claims that an object’s location is grounded by the locations of the larger wholes it helps compose, the spatiotemporal relations it bears with the other components, and its own shape and size. Unlike BUGL, TDGL remains metaphysically neutral regarding the ultimate structure of reality, particularly in the context of classical mereology. We show that TDGL exhibits a gradual character: the way in which an object’s location is grounded depends on the scale or size of the system within which the object is located. Ultimately, we discuss the role of the universe and the impact of its peculiar location on the interpretation of TDGL. 

The Logic and Metaphysics Workshop will host a logic workshop on Friday, April 17th, from 1:00 to 6:30 at the Graduate Center (Room 8400 4419). Details here.

The Logic and Metaphysics Workshop will meet on April 13th from 2:00-4:00 in-person at the Graduate Center (Room 9205) for a talk by Eno Agolli (SKC/CUNY).

Title: Two-Dimensional Monsters

Abstract: Epistemic modality has long threatened to upend well-established tenets of semantic orthodoxy. One target is the Kripkean package about singular terms and de re modality. Against Russell and Quine, Kripke argued that (i) names are rigid, (ii) that descriptions are non-rigid, and (iii) that quantifying into modal contexts is both possible and coherent. But his arguments were built around cases of metaphysical modality. In parallel epistemic cases, the standard Kripkean picture appears to falter. This has fueled a range of revisionary responses, including dynamic, counterpart-theoretic, and impossible-worlds approaches. I argue that this is an overreaction. Working within a two-dimensional framework, I propose that variables at logical form range over two-dimensional individual concepts (rather than individuals). This single, minimal departure from orthodoxy yields a surprisingly unified treatment of the epistemic data and, crucially, retains a version of Kripke’s trifecta.

The Logic and Metaphysics Workshop will meet on March 30th from 2:00-4:00 in-person at the Graduate Center (Room 9205) for a talk by Shin Matsuura (CUNY).

Title: A paraconsistent theory of truth with a connexive conditional

Abstract: The semantic paradoxes show that one cannot retain the unrestricted T-schema while maintaining classical logic. Since Kripke’s “Outline of a Theory of Truth,” it has been known that non-classical theories of truth can maintain the transparency of truth. However, any such theory must also be equipped with a suitable conditional to adequately express the T-schema. In this talk, I propose a paraconsistent theory of truth based on a connexive conditional and report its non-triviality result. Unlike other paraconsistent theories of truth, my proposal is not based on relevance logic. Instead, its underlying logic is an “irrelevant” connexive logic with a simple Kripke semantics and closely related to (sub)intuitionistic logic. I argue that this theory can overcome some difficulties faced by earlier paraconsistent theories of truth, including the treatment of restricted quantification. 

The Logic and Metaphysics Workshop will meet on March 23rd from 2:00-4:00 in-person at the Graduate Center (Room 9205) for a talk by Jamie Beardmore (Columbia).

Title: Mereological Fusions as Mere Manys

Abstract: Philosophical attention to developments in plural logic has led to the theory of “Manyism”: fusions are “mere manys” in that they are pluralities and not also individuals (Thunder 2023; Trueman and Thunder 2025). Manyism gives a further result of “Mereologicism”: the axioms of (atomistic) classical mereology are theorems of higher-level plural logic. Mereologicism (and therefore Manyism) is claimed to secure the ontological innocence of mereology because logic is ontologically innocent, and mereology is shown to be logic. I first investigate the Mereologicist model presented in (Trueman and Thunder 2025) to determine the payoff of going “superplural”. I argue however that Mereologicism may be recovered from standard plural logic. I then raise attention to various semantics for plural logic, to i) argue against the Manyist claim that fusions, qua pluralities, exist in the same sense as individuals; and ii) raise questions of indeterminacy for plural quantification, given a plural analogue of Henkin semantics for second-order logic introduced by Florio and Linnebo (2021). I close by questioning whether Manyism is better suited as a theory of speaker-meaning for everyday talk of mereological fusions, rather than a metaphysical theory distinct from mereological nihilism.