Henry Prakken

I am a professor of Artificial Intelligence and Law in the Responsible AI group of the Department of Information and Computing Sciences at Utrecht University. I have master degrees in law (1985) and philosophy (1988) from the University of Groningen. In 1993 I obtained my PhD degree (cum laude) at the Free University Amsterdam with a thesis titled Logical Tools for Modelling Legal Argument.

My main research interests concern artificial intelligence & law and computational models of argumentation. I am a past president of the International Association for AI & Law (IAAIL), of the JURIX Foundation for Legal Knowledge-Based Systems and of the steering committee of the COMMA conferences on Computational Models of Argument. I am on the editorial board of several journals, including Artificial Intelligence and Law. Between 2017-2022 I was an associate editor of Artificial Intelligence.

LATEST:

Call for papers of COMMA 2026. Submission deadline 18 April 2026.
Call for papers of JURISIN 2026. Submission deadline 10 February 2026.
My promotor and long-time boss John-Jules Meyer passed away on October 22, 2025. Links to an In Memoriam in Dutch and English.
Call for abstracts of a workshop on Argumentation and Online Debates. Submission deadline Jan. 15th, 2026.
Call for papers of ICAIL 2026. Extended submission deadline 31 January 2026.
I co-organised a Symposium on Ethical and Legal Perspectives on Explainable AI, Utrecht (The Netherlands), 16 October 2025.
I was interviewed by the Dutch magazine for lawyers Advocatenblad (2025-2, pp. 34-38) about When do you step into the world of AI?
Slides of my invited talk What information does an algorithmic legal judgment prediction give? at JURIX 2024.
Full text of my inaugural address of Sept. 9th, 2024 [original Dutch version], [translated English version]
An obituary of Trevor Bench-Capon, who passed away on 20 May 2024.
The Handbook of Rationality (eds. Markus Knauff and Wolfgang Spohn) is now open access.
Public announcement of my appointment as full professor on AI and law at Utrecht University, with a brief interview.
I have received the 2023 CodeX Prize of CodeX - The Stanford Center of Legal Informatics, Stanford University, jointly with Trevor Bench-Capon and Giovanni Sartor, in acknowledgement of our work on argumentation theory and its application to the law.
- Press release
- Video of CodeX prize announcement at FutureLaw 2023
My reader Juridische Argumentatie (in Dutch) is now downloadable under Creative Commons license CC BY-NC 4.0 (a layout problem on p. 8 corrected on Dec 6, 2025).
Mijn commentaar als referent op het preadvies van Eric Tjiong Tjin Tai tijdens het jaarcongres 2020 van de Nederlandse Juristenvereniging. De preadviezen zijn hier te downloaden.
John Fox, the leader of the ASPIC project (2004-2007) died on August 31, 2021. Links to a tribute and an obituary.
I was interviewed by the Dutch newspaper NRC about IBM's Debater project.
The special issue of Topics in Cognitive Science on Models of Rational Proof in Criminal Law, edited by myself, Floris Bex and Anne Ruth Mackor, is now online. See also the introduction. With useful case study material for argumentation research, including my argumentation-based analysis of the Simonshaven case.
I am a coordinator of a special-interest group on AI, Ethics and Law of the new UU focus area Human-centered AI.
- Symposium on Ethical and Legal Perspectives on Explainable AI, Utrecht (The Netherlands), 16 October 2025.
- Session on Legal and Ethical Aspects of ChatGPT and Similar Tools during the Meet Human-Centered AI Day, Utrecht (The Netherlands), 4 April 2023.
- Symposium on Law and Artificial Intelligence: Not a World Apart, Utrecht (The Netherlands), 18 May 2022.
I take part in the 19 million euro NWO Gravity project on Hybrid Intelligence.
My invited talk Abstract argumentation does not exist at the ILLC Workshop on The wisdom and madness of crowds: argumentation, information exchange and social interaction.
A new online complaints system of the Dutch Police has ASPIC+ inside. See also Schraagen et al. (2018).
I was interviewed about the 'robot judge' in the Dutch newspaper Trouw.

Some recent and forthcoming papers:
- A JURIX 2025 workshop paper with Anne Ruth Mackor on possibly misleading ways to report likelihood ratio's in criminal cases.
- My handbook chapter with Trevor Bench-Capon, Katie Atkinson, Floris Bex and Bart Verheij on Computational models of legal argument in Vol. 3 of the Handbook of Formal Argumentation.
- My accepted AI Journal paper on dialectical argument strength, combining and extending my COMMA 2022 and KR 2023 papers.
- My KR 2023 paper on expansions in ASPIC+.
- My ICAIL 2021 paper with Floris Bex on the relevance of algorithmic decision predictors for judicial decision making.
- My paper with Rosa Ratsma on argumentation for explainable AI, accepted for Argument & Computation.
- A paper A formal analysis of some factor- and precedent-based accounts of precedential constraint in Artificial Intelligence and Law.
- My CMNA 2020 paper On validating theories of abstract argumentation frameworks: the case of bipolar argumentation frameworks.
- A handbook chapter on Logical models of legal argumentation. In M. Knauff & W. Spohn (eds.): The Handbook of Rationality. Cambridge, MA: MIT Press 2021.
- A TPLP paper with Alejandro Garcia and Guillermo Simari on a comparison between ASPIC+ and DeLP.
- My ICAIL 2019 paper on accrual of arguments.
- My COMMA 2018 paper with Michiel de Winter on the dangers of abstraction in argumentation.
- My KR 2018 paper on probabilistic strength of arguments with structure.
- My chapters in the Handbook of Formal Argumentation on the history of formal argumentation (version August 15th, 2017) and (with Sanjay Modgil) on abstract rule-based argumentation (version July 4th, 2017).
- A corrected version of my 2013 AIJ paper with Sanjay Modgil on the ASPIC+ framework. A note on the corrections.
- A JAIR paper of Diana Grooters and myself Two aspects of relevance in structured argumentation: minimality and paraconsistency (solving the contamination problem in ASPIC+ and other things; an extended version of our COMMA 2014 paper).
- My AI Journal review with Giovanni Sartor on Law and logic: a review from an argumentation perspective. Published AI Journal version. Corrected version A note on corrections.
- My ECAI 2014 paper on abstract support relations