Career
He was its chairman from 1946 to 1969. Van Praag was one of the first professors in Humanist studies in University of Leiden (1964-1979). He played a major role in the founding of the International Humanist and Ethical Union and was its chairman from inception in 1952 until 1975.
There was another Jaap van Praag who live in the same period (Amsterdam, 10 July 1910 - Amsterdam, 7 August 1987).
This Jaap van Praag was chairman of Dutch football club AFC Ajax from 1964 till 1978.
