Fashion Statements: Sartorial Communication and Common Ground

Sanna Hirvonen (LanCog, University of Lisbon)

20 February 2026, 16:00 (Lisbon Time – WET)

Faculdade de Letras de Lisboa

Sala Mattos Romão [C201.J] (Departamento de Filosofia)

Abstract: We learn a great deal about others from what they wear. Outfit choices can signal profession, social class, culture, lifestyle, gender, sexuality, and aesthetic taste. How is such sartorial communication possible? Marilynn Johnson (2022) suggests that clothing can be understood through H. P. Grice’s intention-based account of non-natural meaning. While this proposal shows that clothing can convey communicative intentions, it leaves open crucial questions about how clothes can systematically acquire information potential, and when that information is successfully communicated. I address these questions by developing a framework for sartorial communication, drawing on Robert Stalnaker’s account of context and common ground. Unlike speech, wearing clothes is continuous, and its audience keeps shifting. This raises distinctive problems: What constitutes the context of utterance? Who counts as the intended audience? And what determines the common ground that is required for communication to succeed? I argue, first, that communities generate sartorial conventions through repeated, meaning-conveying use, thereby enabling clothes to acquire non-natural meaning. Second, knowledge of these conventions is required for a shared common ground. Third, since not everyone knows the relevant conventions, sartorial communication is conditional: it succeeds only in contexts where a member of the intended kind of audience is present.

This event is funded by Portuguese national funds through FCT – Fundação para a Ciência e a Tecnologia, I.P., within the project UID/00310/2025, Centro de Filosofia da Universidade de Lisboa (https://doi.org/10.54499/UIDB/00310/2025)

AI Art and Artists: What They Are, What They Could Be, What They Should Be

Dominic McIver Lopes (University of British Columbia)

13 February 2026, 16:00 (Lisbon Time – WET)

Faculdade de Letras de Lisboa

Sala Mattos Romão [C201.J] (Departamento de Filosofia)

Abstract: Generative AI systems provoke important practical questions, but they also provoke existential anxieties, which arise in response either to the reality or the possibility of AI art made by genuinely creative AI artists. This paper first reviews recent arguments that existing AI systems do not make art and are not genuinely creative. It then argues that existential anxieties are not warranted if possible AI artists are just like human artists. Finally, it argues that, if they are not just like human artists, then we should design them to benefit us by satisfying an interest in aesthetic diversity. The upshot is that no existential anxieties are justified. In making this argument, the paper draws lessons about AI art and artists and also about our values and interests.

This event is funded by Portuguese national funds through FCT – Fundação para a Ciência e a Tecnologia, I.P., within the project UID/00310/2025, Centro de Filosofia da Universidade de Lisboa (https://doi.org/10.54499/UIDB/00310/2025)

Metaphysical Indeterminacy of Causal Relations: the Case of the Quantum Switch

Laurie Letertre (University of Munich)

19 December 2025, 16:00 (Lisbon Time – WET)

Faculdade de Letras de Lisboa

Sala Mattos Romão [C201.J] (Departamento de Filosofia)

Abstract: It is often assumed that, if c causes e, then it is determinate that c causes e. Call this principle Determinacy of Causation (DetC for short). In recent years it has been shown that DetC suffers from various objections within a Humean framework for understanding causation (Sartorio 2006, Ballarin 2014, Bernstein 2016, Swanson 2017). Our aim in this paper is to argue that recent discoveries in the foundations of quantum mechanics might give further motivations for rejecting DetC. We focus on a specific arrangement of physical operations known as quantum switch, and show that a mildly realist attitude towards this setup forces us to put DetC into question. We will then briefly discuss the possible origin of this indeterminacy, and highlight some of the consequences of abandoning DetC for theories of causation. (Joint work with Cristian Mariani.)

Deflationism: From Semantics to Ontology

Thomas Schindler (University of Amsterdam)

12 December 2025, 16:00 (Lisbon Time – WET)

Faculdade de Letras de Lisboa

Sala Mattos Romão [C201.J] (Departamento de Filosofia)

Abstract: I present a deflationary account of abstract objects, focusing on numbers and properties. This account can be seen as a natural extension of the deflationary account of truth. Very roughly, the key idea is that (1) our talk about numbers and properties serves a quasi-logical function analogous to our talk about truth, and (2) key questions about the metaphysics and epistemology of numbers and properties can be answered with reference to that function. In contrast to many other deflationary approaches in metaphysics, the present account does not assume that the principles governing our talk about numbers and properties is analytically true.

“A Goblin Walking Quietly Over the Universe”: Artifactual Events and Musical Experience

Simon Evnine (University of Miami)

5 December 2025, 16:00 (Lisbon Time – WET)

Faculdade de Letras de Lisboa

Sala Mattos Romão [C201.J] (Departamento de Filosofia)

Abstract: In this paper, I take my account of the making of artifactual objects and see whether it can apply to artifactual events. I propose several ways in which one might, in line with my approach, make an artifactual event. On the basis of the last of these ways, I engage in a brief discussion of musical experience, which I suggest is a kind of artifactual event.

Some Problems of Normal Form in Logical Metainferentialism

Bogdan Dicher (University of the Witwatersrand)

28 November 2025, 16:00 (Lisbon Time – WET)

Faculdade de Letras de Lisboa

Sala Mattos Romão [C201.J] (Departamento de Filosofia)

Abstract: In “Logical Metainferentialism” (Ergo, forthcoming), Dicher and Paoli develop a theory of harmony for metainferential calculi in the FDE family, including ST. They identify a certain normal form—called there structurally atomic–analytic synthetic (SAAS) normal form—as the mark of harmony. A proof is in SAAS normal form iff it is structurally atomic (the structural rules apply to/produce only atomic formulae) and analytic–synthetic (all applications of elimination rules precede all applications of introduction rules). In “Sequent Calculi for First-Order ST” (JPhiLog, 2024), Paoli and Prenosil introduce a sequent calculus for ST employing generalized elimination rules for the quantifiers. In this talk, I present a calculus for ST in which all elimination rules are in general form, and I discuss which normal forms can be identified for this calculus and their significance for metainferential harmony.

Prime Numbers and Periodical Cicadas: The Case for Mathematical Platonism?

Luca Caiti (LanCog, University of Lisbon)

21 November 2025, 16:00 (Lisbon Time – WET)

Faculdade de Letras de Lisboa

Sala Mattos Romão [C201.J] (Departamento de Filosofia)

Abstract: In his “Are There Genuine Mathematical Explanations of Physical Phenomena?” (2005), Alan Baker proposed an indispensable mathematical explanation for a peculiar biological case: the prime-numbered life-cycles of North American periodical cicadas. Following his “Explanatory Indispensability Argument” (EIA), we should then be ontologically committed to mathematical entities. In this paper, I criticize that view on two main grounds. First, I show that both the alleged indispensability and the explanatory structure Baker offers are fundamentally flawed. In doing so, I draw upon recent biological findings and analyze the discussion in the scientific literature, including a new theory for the phenomenon in question—the so-called “internal-clock theory”. Accordingly, if we take the cicada case study and the EIA, it actually follows the exact opposite of what Baker argued: that his mathematical explanation is not indispensable and that we should not be committed to the existence of mathematical objects. Second, I examine the EIA’s general stance and outline possible ways to reject it, regardless of the indispensability of Baker’s mathematical explanation. Consequently, we shouldn’t endorse such an ontological commitment, even if Baker’s mathematical explanation were indispensable—let alone given that it is not.

Some Problems of Normal Form in Logical Metainferentialism

Bogdan Dicher (University of the Witwatersrand)

28 November 2025, 16:00 (Lisbon Time – WET)

Faculdade de Letras de Lisboa

Sala Mattos Romão [C201.J] (Departamento de Filosofia)

Abstract: In “Logical Metainferentialism” (Ergo, forthcoming), Dicher and Paoli develop a theory of harmony for metainferential calculi in the FDE family, including ST. They identify a certain normal form—called there structurally atomic–analytic synthetic (SAAS) normal form—as the mark of harmony. A proof is in SAAS normal form iff it is structurally atomic (the structural rules apply to/produce only atomic formulae) and analytic–synthetic (all applications of elimination rules precede all applications of introduction rules). In “Sequent Calculi for First-Order ST” (JPhiLog, 2024), Paoli and Prenosil introduce a sequent calculus for ST employing generalized elimination rules for the quantifiers. In this talk, I present a calculus for ST in which all elimination rules are in general form, and I discuss which normal forms can be identified for this calculus and their significance for metainferential harmony.

Against Norms of Knowledge

David Papipneau (King’s College London)

14 November 2025, 16:00 (Lisbon Time – WET)

Faculdade de Letras de Lisboa

Sala Mattos Romão [C201.J] (Departamento de Filosofia)

Abstract: Intuitive support for norms of knowledge (governing assertion, belief and action) comes largely from lottery-like cases in which high confidence is causally unconnected with the facts at issue. I shall argue against knowledge norms precisely because of what they advise in such cases. Where they make a difference, they lead us astray. (I shall also consider the role knowledge plays in our emotional engagement with the world, and show that this too lends no support to knowledge norms.)

This activity is funded by Portuguese national funds through FCT – Fundação para a Ciência e a Tecnologia, I.P., within the project UID/00310/2025, Centro de Filosofia da Universidade de Lisboa
(https://doi.org/10.54499/UID/00310/2025)

What is Purely Epistemic Normativity, and Why? A Study in Wolfian Epistemology

Richard Pettigrew (University of Bristol)

7 November 2025, 16:00 (Lisbon Time – WET)

Faculdade de Letras de Lisboa

Sala Mattos Romão [C201.J] (Departamento de Filosofia)

Abstract: What is the distinction between what we ought to believe simpliciter and what we ought to believe epistemically speaking, and why do we draw that distinction? I motivate this question through a series of examples, consider various existing answers, and find them wanting. Then I propose and explore an alternative based on a version of Susan Wolf’s rule consequentialism transposed to the epistemic realm: the norms that determine what we ought to do epistemically speaking are those such that broad adherence to them across your epistemic community would give the best results from an epistemic point of view. I argue that norms that exhort us to believe only what we ought to believe epistemically speaking follow from this Wolfian version of epistemic rule consequentialism. In a coda, I offer an alternative account of the function of knowledge ascriptions that improves on Edward Craig’s.

This activity is funded by Portuguese national funds through FCT – Fundação para a Ciência e a Tecnologia, I.P., within the project UID/00310/2025, Centro de Filosofia da Universidade de Lisboa
(https://doi.org/10.54499/UID/00310/2025)