In Memoriam Prof. dr. John-Jules Ch. Meyer (1954–2025)
With deep sadness we have learned of the passing of our colleague, mentor and friend, Prof. dr. John-Jules Meyer. For more than thirty years, John-Jules served as Professor at the Department of Computer Science of Utrecht University, where he played a central role in research and education in the field of artificial intelligence and logic. Yet his influence extended far beyond the university: he helped shape the field, nationally and internationally, in part through his role in educating and guiding an entire generation of AI researchers.
Scientific vision and pioneering role
Prof. dr. John-Jules Meyer was one of the pioneers of logic-based artificial intelligence. In the 1990s, he played a central role in the development of epistemic, non-monotonic, dynamic, and deontic logic within AI. He was co-initiator of the international DEON conferences on deontic logic in computer science; the best paper award of this conference series bears his name, and thus continues to honour his legacy. He was also one of the most important advocates of the agent-based approach within artificial intelligence. Thinking in terms of autonomous software agents, with goals and responsibilities, has since become a foundational paradigm in the field.
John-Jules’ scientific output was impressive. He published more than 500 papers and several important books, and gave dozens of keynote lectures at international conferences. In 2005, he was named Fellow of the European Association for Artificial Intelligence (ECCAI/EURAI), a recognition of his lasting contributions to the field.
Supervisor, mentor and inspiring teacher
Perhaps even more important than his scientific achievements was his role as educator and source of inspiration. John-Jules supervised more than 60 PhD candidates and served on more than 200 PhD committees in the Netherlands and abroad. In 2011, nine of his PhD candidates successfully defended their dissertations in a single year, earning him the title of UU supervisor of the year. In the year before that, he supervised more than half of all computer science PhD defenses in Utrecht.
Former PhD candidates and students remember John-Jules as a teacher who explained with clarity and enthusiasm, and as a supervisor who inspired and guided rather than prescribing a fixed path. He was known for his humour, his patience and attentiveness, and the trust and support he gave to his students and PhD candidates. An image remembered by many: John-Jules in the front row at a conference, nodding proudly and eagerly while one of his PhD candidates was presenting.
Administrative contributions
John-Jules also helped shape and develop the field through his many administrative roles. Among other roles, he was co-founder and scientific director of the SIKS research school, research director of the department of Computer Science, chair of the Association for Logic and Philosophy of the Exact Sciences, representative of Computer Science on the Joint Committee, and board member of IPN (ICT research Platform Netherlands). Within Utrecht University, John-Jules played an important role in the Cognitive Artificial Intelligence study programme, the precursor to the current bachelor’s and master’s programmes in Artificial Intelligence.
Legacy
John-Jules leaves behind an impressive scientific body of work, but his greatest legacy lies in the people he taught and inspired. We are grateful for his dedication and for the vision and inspiration with which he helped shape both the field and the many students and PhD candidates he supervised. We will miss his sharp mind, tireless commitment, humour and warm collegiality.
Our thoughts are with his loved ones, colleagues, and former PhD candidates and students.
Jan Broersen, Mehdi Dastani, Henry Prakken, Nieske Vergunst, department of Computer Science