My work is independent of my will. My best works are created when driven by an inner strength. This has nothing to do with my will. It is that immediate spontaneity of my intense way of living that makes the difference between my work and a lot of other artists who make art works with their mind.

Letter to H. E. Kramer, 14-11-1927, as quoted in: Bram van Velde, A Tribute, Municipal Museum De Lakenhal Leiden, Municipal Museum Schiedam, Museum de Wieger, Deurne 1994, p. 46 (English translation: Charlotte Burgmans)