​Research

I have been working on a series of related topics and themes over the past few years, as I try to outline below. By clicking on the links you find some of the publications this has resulted in. For an exhaustive, non-narrative overview of my publications, I refer to my CV and this page (which contains downloadable pdfs of most of my published papers and working papers). I'm always in for discussing these topics or starting up collaborations on them. Feel free to contact me if you would have any questions or suggestions, or if you simply have trouble getting access to any of the mentioned papers.

Pooling and pointwise intersection

​When agents have (possibly conflicting, unprocessed, piecemeal) evidence, norms, plans, or other sorts of information, we may ask what would happen if they pool this information, i.e. combine it in order to e.g. determine what the group knows, wants, or intends. In this joint research with Dominik Klein, I investigated the logic of such claims, using and extending existing tools from modal logic. At the moment we have one conference paper, and one article published in Studia Logica, based on this work. Our forthcoming paper in the Journal of Philosophical Logic concerns the same theme, focusing on issues of expressivity and communication dynamics.

Group agency and collective obligations

​""Should we, as a group, have done X rathery than Y?"  "I had no obligation to ensure Z, since by myself I was unable to do this!" Expressions of this sort are ubiquitous in everyday reasoning and political discourse, but we often hardly have a clue whether they can be true at all, and if so, what their truth conditions are. In recent work with Allard Tamminga and Hein Duijf I have been using game-theoretic semantics and formal logics to study expressions concerning group agency and collective obligations. This resulted in a conference paper that we presented at LORI2017, a  Synthese paper, a paper in Philosophical Studies, and some more work in progress. Relatedly, I guest edited an issue of Logique et Analyse on "Collective Agency, Games, and STIT Logic".

Deliberation, aggregation, and democracy

​"This is my most recent research line, much influenced by discussions with Olivier Roy and his group at the University of Bayreuth where I was a Marie Curie fellow. While traditional social choice theory studies the way preferences, opinions, and other types of information can be aggregated, mainstream political theory emphasizes the importance of group deliberation: people should talk, exchange arguments, revise their preferences, and pool their knowledge before casting a vote or reaching agreement. My aim with this research is to develop formal models of deliberation, combining tools from modal logic, deontic logic, and dynamic epistemic logic. Relared to this research line, I organized the DYCODE lectures on Collective Decision-Making: Formal Tools and Philosophical Perspectives  at the University of Bayreuth and developed course material for high school students.
Since April 2021, this research line is at the center of my VIDI project entitled ENCODE: Explicating the Norms of Collective Deliberation. See this page for more information.

Deontic Logic

​"Each of the above topics relate, in one way or another, to deontic logic: the logic of obligation, permission, and any notion that is crucial in moral reasoning.  Other than the aforementioned work, I have been studying the concept of deontic sufficiency (leading to this article in Erkenntnis) and linked this to the idea of obligation as weakest permission (see this paper in the Review of Symbolic Logic), and the logic of deontic claims concerning coarse-grained alternatives (see this article in the Journal of Logic and Computation). More recently I was invited to become co-author of the Stanford Encyclopedia of Philosophy-entry on Deontic Logic. I also proudly co-chaired the 15th International Conference on Deontic Logic and Normative Systems (DEON2020/2021) with Alessandra Marra, Fenrong Liu, and Paul Portner; see this link for the proceedings (open access). 

... and more...

​"I like to read and work on a variety of topics, and I much prefer teamwork over solitary investigations. Here's a non-exhaustive list of other topics I have been working on, in the past, or more recently:

1. ​The "problem of no hands": whether there exist cases of group decisions for which no individual member of the group can be held responsible. I studied this topic with Hein Duijf since the summer of 2019, and we published this paper in Social Choice and Welfare.
2. ​Rawls' Theory of Justice, and in particular, his claim that under the veil of ignorance, people will make choices that coincide with what the Difference Principle would proscribe. In joint work with Thijs De Coninck I have developed a formal semantics and logic that allow us to verify this claim and define various deontic logics based on a notion of fairness. In ongoing work we are providing an axiomatization for the class of social choice rules that can be grounded in original position arguments.
3. Term modal logics: modal logics that allow one to quantify over agents. These are a very natural vehicle for the formalization of claims such as "every doctor has the obligation towards each of their patients to respect their autonomy" or "whenever agent x receives evidence from one of its friends, then that evidence is reliable". I have worked on such logics with Stef Frijters and Joke Meheus over the past two years.​
4. Non-monotonic logic, defeasible reasoning, and adaptive logics. This was the subject of my PhD thesis, in which I studied both general metatheoretic issues related to adaptive logics, and applications in terms of deontic logic, abductive reasoning, and belief revision. Much of this work was joint with Christian Strasser, Mathieu Beirlaen, and Joke Meheus. Relatedly I also worked with Christian on the preferential semantics of non-monotonic consequence relations, cf. this paper in the Journal of Philosophical Logic.
5. ​Belief revision, in particular the notion of propositional relevance in belief revision. There is a central intuition in the theory of belief revision that, upon receiving new information, an agent should only change those beliefs that are "relevant" to this new information. But what exactly does this mean? Continuing the work of Rohit Parikh and David Makinson, I tackled this subject together with my former co-supervisor Peter Verdée, resulting in papers in Synthese, Logique et Analyse, and the Journal of Logic and Computation.
6. ​Truthmaker semantics, and hyperintensional logic more generally, caught my attention a few years ago due to the efforts of Albert Anglberger, Johannes Korbmacher, and Federico Faroldi. With Federico, who is meanwhile a colleague at Ghent University, I am co-editing a book in the Springer Outstanding Contributions to Logic series, entitled "Kit Fine on Truthmakers, Relevance, and Non-classical Logic". This book will collect 15 original contributions, an autobiography, and extensive commentaries by Kit on each of the chapters.

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