a Belgian philosopher, born about 1625 at Antwerp, died about 1668 as professor of philosophy at Leyden. He at first taught the classics and the Cartesian philosophy at Louvain, but subsequently wemnt to Leyden, where he abjured Catholicism, and finally obtained the chair of philosophy, which he retained until his death. He was the most remarkable disciple of Des Cartes prior to Spinoza and Malebranche, and his writings contain the germs of some of the doctrines of these later philosophers. He in particular developed the hypothesis of occasional causes. He wrote Ethica (Amsterdam, 1665); Logica (Amsterd. 1662); Metaphysica (Amsterd. 1691). (A.J.S.)