Deusing, Antonius (1612-1666); Drijfhout, Abraham Jacob (1733-1765); Oosten de Bruyn, Gerrit Willem van (1727-1797)

Gert-Jan C. Lokhorst


G.J.C. Lokhorst. "Antonius Deusing (1612-1666)", "Abraham Jacob Drijfhout (1733-1765)", and "Gerrit Willem van Oosten de Bruyn (1727-1797)". In Wiep van Bunge, Henri Krop, Bart Leeuwenburgh, Han van Ruler, & Paul Schuurman, eds., The Dictionary of Seventeenth and Eighteenth-Century Dutch Philosophers. Thoemmes Press, Bristol, 2003.

Deusing, Antonius (1612-1666)

Antonius Deusing was born in Mörs (in the region of Kleve) in 1612. He studied at the Gymnasium Illustre in Harderwijk and was enrolled as a student in Leiden in 1631. In Leiden, he studied physics and logic under F. Burgersdijk, Arabic, Persian and Turkish under J. Golius, and medicine under A. Vorstius and others. He became a doctor of medicine in 1637. In 1639, he became a physician in Mörs and a teacher of mathematics at the local gymnasium. At the end of the same year, he was appointed as a professor of physics and mathematics at the Gymnasium Illustre in Harderwijk. From 1640 on, he also taught astronomy, and from 1642 on, he was also a professor of medicine. In addition to this, he was the archiater (first physician) of Harderwijk. In 1647, Deusing was appointed as a professor of medicine in Groningen. In 1648, he became a professor of philosophy as well. He was the rector of the Academy of Groningen in 1648 and 1653. On top of this, he was the archiater of the province of Groningen and the chief body physician of Willem Frederik, stadholder of Friesland. He died in Groningen in 1666.

In his inaugural oration at Harderwijk (1639), Deusing gave an account of the method of inquiry he deemed appropriate for the natural sciences. One should start with the Bible. Where the Bible is silent, one should be guided by the senses and reason. The opinions of the classical authors, particularly those of Aristotle, should always be kept in mind, but whenever these are in conflict with the Bible, the senses or reason, the latter are the final arbiters. Subjects which are capable of mathematical demonstration, on the other hand, should always be treated mathematically. Deusing's Naturæ theatrum universale (1642) and De mundi opificio (1643) exemplify this methodology.

In 1643, one of Deusing's colleagues, the theologian J. Cloppenburg, a friend of Voetius, began to protest against some of Deusing's opinions about the soul, the relationship between God and His creation, and the nature and functions of the angels. Cloppenburg tried to have Deusing condemned of heresy, but he did not succeed and left Harderwijk in 1644.

Undeterred by Cloppenburg's objections, Deusing continued his philosophical work in his De anima humana dissertationes philosophicæ (1645), in which he proposed a modification of Aristotle's view that the soul is the entelecheia of the body: he argued that, in man, one should distinguish between an anima sensitiva which cannot be separated from the body and an immortal anima rationalis which is attached to the body through the intermediation of the anima sensitiva. He elaborated this view in his OEconomus corporis animalis (1661), an attack on Walter Charleton (1619-1717), in which he maintained, first, that the anima rationalis is not incapable of knowing itself, and second, that the infant's rational soul (in contrast to his sensitive soul) is not derived from the parents' rational souls, but created afresh by God.

Most of Deusing's numerous writings were concerned with the natural sciences rather than philosophy in the modern sense of the word. He generally adopted the most conservative position compatible with the scientific knowledge of his time. Thus, he preferred Tycho Brahe's geocentric reformulation of the Copernican model of the solar system to Copernicus's own heliocentric model (Kepler's alternative to the theory of epicycles was altogether too novel to his taste). Similarly, he accepted Harvey's discovery of the circulation of the blood, but continued to regard Hippocrates, Galen and Avicenna as the greatest medical doctors of all time. He was especially appreciative of Avicenna. In his inaugural oration in Groningen (1647), he defended Galen's thesis that one cannot be an excellent doctor without also being a philosopher and described Avicenna as the best example of a medicus absolutus whose knowledge is not restricted to medicine but encompasses all branches of philosophy.

Towards the end of his life, Deusing wrote a series of polemical attacks on the speculative iatrochemical theories of the famous Leiden professor of medicine François de le Boë Sylvius (1614-1672). In these writings, he repeated a point that he had already made in his inaugural oration in Harderwijk: experience and experiment do not have the last word in medicine because reason is at least as important. On account of this view and his other predilections, Deusing has been described as the last representative of scholasticism in the faculty of medicine in Groningen.


This is only a selection. See De Haan (1960, pp. 163-8) for a longer list.


Drijfhout, Abraham Jacob (1733-1765)

Abraham Jacob Drijfhout was born in Deventer in 1733. His father was a vicar, his mother the daughter of a vicar. He studied theology, philosophy, oriental languages, medicine, mathematics and astronomy in Utrecht and received the degree of doctor of philosophy in 1755. In 1756, he became a vicar in Zuilen and married a vicar's daughter. He was appointed as a professor of philosophy, mathematics and astronomy at the Geldersche Hogeschool in June 1763. He died less than two years later, in March 1765.

Drijfhout was a more conservative philosopher than his predecessor in the chair of philosophy, mathematics and astronomy in Harderwijk, Van Lom (1704-1763). In his essay On the use and abuse of reason in philosophy, defended under J. Castiglione in Utrecht in 1753, he emphasized the limitations and fallibility of human reason, which can reach no absolute certainty except in mathematics. He mentioned the problem of the relationship between the body and the soul as an example of a problem in which the limitations of reason are clearly visible. His dissertation On the inconsistency of the morality of human acts with the principles of some recent authors (1755), supervised by J. Horthemels, "the last of the Aristotelians in Utrecht," was directed against eudemonism in ethics and attacked the school of natural law as represented by J. J. Burlamaqui's widely used textbook Principes de droit naturel (1747). Drijfhout maintained that politics and morality cannot be founded on reason but only on divine revelation. In his inaugural oration On the utmost necessity of philosophy in our time (1764), Drijfhout argued that philosophy should defend theology against the free-thinkers, esprits forts and philosophes of the time. To prevent misunderstanding, it is to be noted that Drijfhout used the term "philosophy" in a very wide sense: he saw it as consisting of logic, mathematics, physics, astronomy, metaphysics, ontology, pneumatology (the study of the nature of the soul), natural theology, and practical philosophy. Drijfhout's courses in Harderwijk were concerned with philosophy in this wide sense, and in particular with astronomy and Newtonian physics. However, his career was too short to leave many traces.



Oosten de Bruyn, Gerrit Willem van (1727-1797)

Gerrit Willem van Oosten de Bruyn was born in Amersfoort in 1727. He moved to Haarlem at an early age, studied law in Utrecht and became a Master of Both Laws (secular and ecclesiastical) in 1748. He then moved back to Haarlem, where he lived as a man of independent means. He became a member of the city council of Haarlem in 1787 and was mayor of Haarlem in 1789 and 1790. He moved to his country house Randenbroek, near Amersfoort, in 1795 and died there in 1797.

In his dissertation, On the crime of suicide (1748), Van Oosten de Bruyn gave a broad survey of the opinions of the Bible, the classical Jewish, Greek and Roman writers, and some prominent authors of his own time, on the act of suicide. He concluded that suicide is a crime according to natural law and is rightly condemned as a crime in secular and ecclesiastical law. He was therefore less audacious than Hume, who wrote his essay "Of suicide" only a few years later.

Van Oosten de Bruyn's treatise On the progress that those mortals who have never known the divine relevation have made in ethics by the light of reason alone (1758), which won him a prize offered by the curators of J. Stolp's bequest, bore more signs of the Enlightenment. In this work, Van Oosten de Bruyn started by arguing that morality does not depend on divine revelation: God has endowed all human beings with a sense of justice and a conscience, and a basic form of morality is to be found in all societies in all times. Van Oosten de Bruyn quoted several passages from Voltaire's Poème sur la loi naturelle (1752) to illustrate this thesis, which is remarkable because the public hangman of Paris burned this poem in 1759. Van Oosten de Bruyn went on to argue that it is, however, impossible to construct a clear and well-founded system of ethics without employing the idea of an omniscient, impartial God who judges us after death and punishes us for our sins while rewarding virtue. The ethical systems of Pythagoras, Socrates, Plato, Aristotle and the Stoics bear this out: even though these systems cannot be regarded as totally immoral, they have many blemishes and obscurities because they do not rest on this solid foundation. It follows from this that, in ethics, reason can play only a limited role: ethics must ultimately be based on the Christian conception of divine judgment after death, and we owe this conception to divine revelation rather than unassisted reason.

Although Van Oosten de Bruyn's essay attracted some attention at the time it was published, it did not have much impact and was soon forgotten. His history of Haarlem (1765) was rather more successful in this respect.



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