Paul van Ulsen (1946 - 2023)


In memoriam Paul van Ulsen (1946 - 2023)

by Johan van Benthen

On 23 September 2023, Paul van Ulsen passed away, after a serious health problem led to a subsequent period of decline. Paul spent his last years in the warm and safe environment or the health care home Het Hendrickzhuis in Amstedam.

Paul van Ulsen studied philosophy at the University of Amsterdam. He was well-known among his fellow students for his originality of mind, his wide-ranging bibliographical interests, and his unique style of solemn spoken Dutch. Pauls’ subsequent life was not always easy, necessitating a range of menial jobs to support  himself, including that of being a nightwatchman. Even so, he always kept up his intellectual connections with the academic world. Paul was involved with various archives, like that of E.W. Beth, and in particular also that of L.E.J. Brouwer. He played an important role in making sure that these major archives found a permanent home in the National Science Archive in Haarlem. 

He was also a member of an NWO-sponsored research project on the history of the Significs Circle which brought to light many new insights into this highly original Dutch school of thought. In addition, Paul always maintained a presence at the Institute for Logic, Language and Computation at the UvA in Amsterdam, where he served as an honorary librarian for many years.

Paul’s main academic achievement is his authoritative dissertation “E.W. Beth als Logicus”, defended in the year 2000, supervised by Johan van Benthem and Anne Troelstra, available online at Paul had a unique knowledge of the origins and development of all the major strands in Beth’s work, mathematical and philosophical, and of the extensive international organizational network that Beth created, which forms the basis of later institutional developments of logic at the University of Amsterdam. 

At the same time, the dissertation also shows its protagonist Beth as a human being through the judicious use of informal archival material, often showing flashes of Paul’s characteristic dry humor.

Our community has lost a striking personality and a loyal friend.

Personal statement by Dick de Jongh

For many years my dealings with Paul just concerned the university library. Which new books did the ILLC need? After his PhD in which I was only involved by way of his committee he approached me with a problem he hadn't solved in his dissertation: did Beth invent his second kind of models for intuitionistic logic himself, or did he owe them to Kripke? For me this was also a personal matter, Beth inotrduced these models just before I started my studies with him and assigned them to me. The ensuing cooperation worked out very well: my memory didn't help, but Paul knew the material that was available perfectly. The writing was mostly left to me. We came to the happy conclusion that in all probability Beth created these
now called Kripke or possible world models by himself as a natural extension of earlier work. Our library dealings continued and intensified, but another task was added to our pleasant cooperation. The editing of a digital historical dissertation series (HDS) of the ILLC. He did most of the work. When he fell sick this cooperation came to an end but after a period of stagnation the work on the series continues without him in cooperation with Marco Vervoort and  Peter van Ormondt. The series is steadily extending. When I work on the series his solid reliability and gentle humour always come back to me.

Personal statement by Kees Doets

Paul usually was his quiet and friendly self. I remember him once offering, without the least hesitation, his last hard copy of my thesis in order that he could scan the loosened separate pages and let the scan survive in our electronic archive.

Personal statement by Peter van Emde Boas

Paul and  me were roommates since the last rearrangement of rooms at the ILLC. We had desks facing each other, but on occasions we couldn’t see each other due to the boxes and stacks of books and documents Paul used for his work as a librarian and his archival tasks for the Beth and Brouwer archives. Due to my irregular presence since my retirement I don’t know how frequently he was working there.

A recurring theme in our conversations was the decline of paper based libraries and the way institutes are disposing of their printed collections under the onslaught of digitalization. We were in total agreement on this issue but the way Paul was fulminating is something to remember forever. As a positive side result, some of the material to be disposed ended up in my private collection. 

Inspecting my archives (pictures, printed announcements and old calendars) I discovered that Paul also was active as a researcher in the years 2014-2017. He was chief researcher in one of the subprojects of the program “From Criticism to Methodology” which was organized from the Erasmus University Rotterdam. The research seminars were mostly held at the ILLC. One of the participants (possibly Paul, but Gerard Alberts is also possible) got me involved. Other ILLC participants were Joop Niekus, Theo Janssen and Lex Hendriks. My records show that Paul has given at least five presentations in this seminar. 

The project involves historical research on the Significa program of Gerrit Mannoury, in relation with work of Beth and van Dantzig. A main result of the project is the biography of Mannoury by Mireille Kirkels which she defended as a ph.d. thesis at the Erasmus University in Rotterdam in 2019. I was an irregular participant, but I have learned a lot about the scientific world in the Netherlands before and after the second world war. 

It is a tragedy to have lost this fighter of the preservation of Culture.