By Klaas van Berkel

Beeckman was born on December 10, 1588, in Middelburg, capital of the province of Zeeland. His father was a well-to-do candle-maker, who could afford to send his son to Leiden to study theology (1608-1611). In Leiden Beeckman also studied mathematics with the Ramist philosopher Rudolph Snel. Because of dogmatic differences between his father and the leading theologians and ministers in Zeeland, Isaac Beeckman could not find a place as a minister and decided to become a candle-maker like his father. From 1612 to 1616 he had his own workshop in the city of Zierikzee. There, he also repaired water-pipes in breweries and in gardens of wealthy regents. In 1616, however, he handed over his shop to his assistant and went back to Middelburg to study medicine. In 1618 he took his degree at the French university of Caen with some Theses de febre tertiana intermittente.

Since the beginnings of his studies, Beeckman had always kept a notebook, the present Journal. This miscellaneous collection of notes contains remarks pertaining to his personal life, the weather and the social circumstances under which he lived, but also to medicine, logic, music, physics and mathematics. From this Journal, it is clear that already in Zierikzee Beeckman had developed a coherent mechanical philosophy of nature, of which atomism, a modern principle of inertia, and a drive for a mathematical interpretation of natural philosophy are the main ingredients. Only in the Corrolaries to his thesis Beeckman published some of his ideas.

After returning from France, Beeckman went to the city of Breda to help an uncle. There in Breda, in November 1618, he met the young René Descartes. In the last two months of 1618 they discussed several topics in mechanics and mathematics, including the law of falling bodies. The next year Beeckman became a teacher at the grammar school (or Latin school) in Utrecht. In April 1620 he married Cateline de Cerf from Middelburg, who bore him seven children. In December 1620 Beeckman moved to Rotterdam. There he became an assistant to his younger brother Jacob, who was the principal of the local grammar school. Beeckman very much liked the practically oriented atmosphere in Rotterdam. Together with some craftsmen and a physician he founded a Collegium Mechanicum, in which he discussed all kinds of practical problems. Nevertheless, in 1627, because of conflicts within the Dutch Reformed Church in Rotterdam, Beeckman accepted anoffer to become the principal of the grammar school in nearby Dordrecht. He opened his lessons in Dordrecht with a lecture on his so-called 'philosophia physico-mathematica' .

By this time Beeckman had a fully developed mechanical philosophy. He started from the assumption that no explanation in physics was acceptable that did not allow for a pictorial representation. Therefore he rejected the concept of the impetus and instead opted for the idea that an object that is set in motion will always continue to do so unless it is interrupted or deflected. Beeckman also rejected the Aristotelian matter theory and embraced atomism, even though he was aware of its problems. Finally he rejected the notion of the 'fuga vacui' and favored the idea that air pressure was responsible for the behavior of fluids. Starting from ideas like these, Beeckman was able to give mechanical explanations of many different physical phenomena, including magnetism, the tides, the propagation of sound, musical harmonies and the movement of the planets (he was a Copernican).

Around 1630, Beeckman renewed his friendship with Descartes and established friendly relations with two other French philosophers, Mersenne and Gassendi. The relationship with Descartes however cooled down considerably after 1631, when Descartes got the impression - unfounded as it was - that Beeckman was boasting of being Descartes' teacher. In the mid-1630s Beeckman spent considerable time learning the art of grinding lenses. Isaac Beeckman died of tuberculosis on May 19, 1637.

Due to his natural shyness and modesty, Beeckman never published his novel ideas. Only several years after his death his younger brother Abraham published a selection of the entries in the notebooks, the Mathematico-physicarum meditationum, quaestionum, solutionum centuria (Utrecht 1644). But it was a publication too obscure to have an impact on the history of science. Had that been all, Beeckman would have remained a shadowy figure in the background of the Scientific Revolution. In 1905 however, the historian of science Cornelis de Waard rediscovered the lost notebooks of Beeckman and published them between 1939 and 1953, including a supplement with many documents pertaining to Beeckman that have since been lost due to the Second World War. The present Journal is a splendid piece of work, but one should be careful in using it, since De Waard heavily edited the notebooks and left out several notes (on family business and meteorology for instance). One is advised to take good notice of De Waard's own introductions. Since its publication, except for the auction catalogue of his library, not many new documents regarding Beeckman have shown up.