Patterns of Truth: Location and Modality

Gabriel Uzquiano (University of Southern California)

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

Faculdade de Letras de Lisboa

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

Abstract: When is a proposition true at a location, whether a time, a place or a world? And what is it for a proposition to be true exactly at a given location, as opposed to being true all over or entirely within that location? We develop a unified modal framework for these distinctions designed to capture a family of locational relations for propositions, but we find that exact location is resistant to the treatment. We argue that to be true exactly at a location is not just a matter of what pattern of truth across locations a proposition may exemplify.

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)

Questions in the Language and Logic of Thought

Salvador Mascarenhas (École Normale Supérieure, Institut Jean-Nicod)

6 March 2026, 16:00 (Lisbon Time – WET)

Faculdade de Letras de Lisboa

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

Abstract: When making decisions, humans manipulate mental representations of relevant accessible facts to produce new representations which support one or another course of action. At first glance, we would expect these mental representations to correspond precisely to our best independent guess as to what symbolic systems best support rationality: classical logic and classical probability theory. Yet, there is ample evidence from natural-language semantics that various non-classical symbolic systems provide theories of natural-language meaning that have at least the same empirical coverage as classical theories, while providing explanatory insights into meaning which are inaccessible to classical theories. Might this mean that mental representations more generally have the very non-classical properties found in investigations of linguistic meaning? In this talk I argue that they do. I give two case studies which illustrate how a non-classical account of disjunction based on theories of question meanings can shine light on puzzles of human reasoning and decision making, in particular the puzzles of reasoning by representativeness studied by Tversky and Kahneman. I conclude with preliminary but highly suggestive evidence that these kinds of non-classical mental representations are involved in causal representation and inference.

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)

É com enorme prazer que informamos a comunidade académica do lançamento do canal de Youtube do grupo HPhil. Nele será possível seguir os eventos do nosso grupo, com especial destaque para as sessões do nosso seminário permanente – https://www.youtube.com/@HPhilCFUL

It is with great pleasure that we announce to the academic community the launch of the HPhil group’s YouTube channel. The channel will provide access to our group’s events, with particular emphasis on the sessions of the HPhil’s permanent seminar – https://www.youtube.com/@HPhilCFUL

Primitivist Views of Belief and Knowledge

Pascal Engel (EHESS, Paris)

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

Faculdade de Letras de Lisboa

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

Abstract: Two theses about belief and knowledge have dominated contemporary analytic philosophy: (A) Knowledge is a kind of higher-grade belief; (B) Propositional attitudes are relations to propositions. Both theses have been criticized: (A) by those defending the “knowledge first” program in epistemology, who claim that any definition of knowledge is bound to be circular and that knowledge is “prime”, and (B) by Arthur Prior and some phenomenologists, who have claimed that belief should not be understood as a relation between an attitude (or a mode) and a proposition, but only the entertaining of a content. On this view, sometimes called “prenectivist”, there are no attitudes as ordinarily construed: there are only kinds of contents, which determine in which kind of attitude a subject is at a given moment.

Let us call these views about knowledge and belief primitivist: knowledge cannot be decomposed as a conjunction of true belief and some other factor, and belief is not relational, but only the instantiation a certain kind of content. The arguments in favour of the knowledge first view are well known, and I shall not rehearse them, except the circularity argument. The (B) view of belief can also be labelled “belief is prime”. I shall in particular ask whether they both give priority to objects rather than propositions. Both views have the consequences that belief and knowledge are very different kinds of states.

One version of the (A) view is that knowledge is basically objectual knowledge (knowing Sintra, knowing Pessoa) rather than knowledge that (knowing that Sintra is not far from Lisboa). It is basically Russell’s notion of acquaintance. Recently a version of the knowledge first program has been defended by Maria Rosa Antognazza (2024), who argues, on historical grounds, that knowledge is an undefinable form of assent or grasping of objects.  The primitivist version of the (B) view is defended among others, by Uriah Kriegel (2022).

I would like to defend several objections to these primitivist conceptions of knowledge and belief. One can agree with the primitivist conception of knowledge without agreeing that (a) the fact that any definition of knowledge is circular entails that knowledge cannot be characterized by certain marks (sensitivity, safety, reliability) which do not amount to justified belief, (b) the fact that a long historical tradition has accepted a view of knowledge as a primitive state graspable by intuition does not imply that there is no room for a notion of knowledge as belief plus a justificatory factor, (c) that there is an important difference between objectual knowledge by acquaintance and propositional knowledge by description does not entail that the latter is based on the latter, (d) that the non-attitudinal and non-relational view of belief has many problems and fails to be a genuine alternative to the relational view.

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)

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.