Dutch philosopher and pioneer in experimental psychology.
He was the son of Jan Hendrik Heijmans (18 July 1813, Leeuwarden – 19 April 1874, Leeuwarderadeel), notary and later municipal, and Sara Henriëtte Wijsman (? Amsterdam – 3 September 1884, Leiden).
After HBS secondary education in Leeuwarden (16 July 1874), he studied law and philosophy in Leiden University under Jan Pieter Land, Simon Vissering and Joannes Buys. He passed his exams in public law on 23 October 1879 cum laude and on 29 June 1880 he was awarded a cum laude PhD on a dissertation in Political Economics “Karakter en methode der staathuishoudkunde” (Character and method of political economy) under Jan Pieter Nicolaas Land. He continued his philosophical studies in Germany where he earned a second D.Phil degree with Zur Kritik des Utilismus (Freiburg, 1881) under Wilhelm Windelband.
On 15 September 1881 he married Anthonia Berendina Theodora Barkey. Little is known of her, except that she was artistic, well educated and his favourite experimental subject. They got no children.
On 21 May 1883 he became a private lecturer in philosophy in Leiden, giving classes in “principles of mathematics and natural sciences”. On 18 June 1890, he was appointed professor at Groningen in the faculty of arts and philosophy with the task of teaching in the history of philosophy, logic, metaphysics and psychology. On 27 September 1890, Heymans took office with the inaugural lecture: Het experiment in de philosophie (experiment in philosophy).
Heymans was influenced by the ideas of the Russian Neo-Kantian philosopher of Greek-German descent, African Spir (15 November 1837 – 26 March 1890) and the German philosopher, physicist and experimental psychologist Gustav Fechner. In Groningen, Heymans founded the first laboratory for experimental psychology of the Netherlands. He was probably the first Dutch experimental psychologist (even before the word psychologist existed) studying paranormal phenomena. In parapsychology, Heymans conducted like Wilhelm Wundt the experiment using quantitative methods. In 1919 he was the the first chairman of the Studievereniging voor Psychical Research (SPR).
He was regarded as an eminent teacher. In 1900 he became member of the Royal Netherlands Academy of Arts and Sciences, he resigned November 1919. He got many international awards, but sent back a French award in protest of the Dreyfus affair. In his last decades he had eye problems.
He died 18 February 1930 in Groningen.
On June 11, 1944, the Heymans-Genootschap (1944-1962) was established. The University of Groningen still harbours a Heymans Institute (Psychology) and a Heymans Building (top reached on 3 March 2008), which accommodates the Faculty of Behavioural and Social Sciences.

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