Science in Christian Perspective

In Memoriam

Reijer Hooykaas (1906-1994): 
A Modern Advocate for Philosophia Libera

Arie Leegwater*

Department of Chemistry and Biochemistry
Calvin College, Grand Rapids, MI 49546

On January 4, 1994, one of the leading Christian historians of science in the worldˇand one of only two honorary members of the American Scientific Affiliation (ASA)ˇpassed away. It was a passing not recognized to any great extent in the Anglo-Saxon world. Yet Professor Reijer Hooykaas exerted a great influence on many in the United Kingdom and North America through his writing and lecturing activities. He repeatedly spoke at conferences of Christians in Science, formerly known as The Research Scientists' Christian Fellowship (RSCF) in the UK, including the joint 1985 RSCF/ASA Conference at Oxford University. He also lectured with his close friend, Professor Donald MacKay at Regent College. There is a certain irony in this: namely, that his life and work, particularly his Christian witness, were often more recognized and appreciated by foreigners than by his own countrymen.1 I would like to give the reader a brief sketch of Hooykaas's life and some of his more important contributions to the history of science.2

History of science was not a large enterprise in the Netherlands in the 1930s. There were a number of privatdocenten, Eduard J. Dijksterhuis the author of The Mechanization of the World Picture (1950/1961) comes readily to mind.3 However, in 1945 the Free (Vrije) University of Amsterdam had the foresight to appoint Hooykaas to the first chair in the history of science in the Netherlands. All students in the natural sciences and mathematics were required to take his course in the history of science. Students could also select history of science as a bijvak (minor). According to my count, Hooykaas had four promovendi, one of whom, Harry A.M. Snelders, became director of the Institute for the History of Science at the University of Utrecht. Hooykaas himself later moved to Utrecht as professor in 1967 until his retirement in 1976. From 1948-1960, Hooykaas taught mineralogy to chemistry students at the Free University and was instrumental in establishing its mineralogy collection.4

Hooykaas was trained as a chemist, taught chemistry at two secondary schools from 1930-1946, and in 1933 defended a dissertation entitled Het Begrip Element in zijn historisch-wijsgeerige Ontwikkeling (The Concept Element in its Historical-Philosophical Development) at the University of Utrecht. In 1934 at a Free University scientific gathering, he gave a clear indication of his interests and concerns in a lecture entitled Natuurwetenschap en Religie in het Licht der Historie (Science and Religion in the Light of History). An article on Pascal in 1939 and a lengthy study of Robert Boyle, Een Studie over Natuurwetenschap en Christendom, soon followed.5

For many years, Hooykaas also played an active role in the Christian Society of Scientists and Physicians in the Netherlands. In 1948 he first lectured at the annual conference of the RSCF in London upon the invitation of Dr. Martyn Lloyd-Jones. As Hooykaas increasingly began to lecture and publish in English, his work became more widely recognized and respected. He served as Vice-President for Europe (1967-1976) and then as President of the International Committee on the History of Geological Sciences (1976-1984). In 1970 he presented the Erasmus Lectures at Harvard University and in 1975-1977 the Gifford Lectures at the University of St. Andrews.6

Hooykaas was a professor of the old school: well-read, proficient in languages, and "lord" of his domain.

Hooykaas was a professor of the old school: well-read, proficient in languages, and "lord" of his domain. He did not suffer fools gladly, whether they were under-prepared students coming for an oral examination or historians of science who used and abused his work without acknowledgment. His facility with languages was legendary. Dutch, English, French, German, Latin, Polish, and Portuguese were at his command, and he let university students know itˇoften to their embarrassment. Hooykaas frequently described himself as an old-fashioned Calvinist, not enamored by contemporary theological and philosophical movements in the Netherlands. For example, one finds a few references to theologians such as Abraham Kuyper and Herman Bavinck in his early work, but none to Gerrit Berkhouwer in his later writings; and none at all, that I could discover, to contemporary philosophers such as Herman Dooyeweerd or Dirk T.H. Vollenhoven.

Hooykaas was his own person. No shades of Kuyperian triumphalism for Hooykaas: "just" patient humble inquiry. No call for the "Christianizing" of disciplines or the "inner reformation of the sciences." Pure, good science is Christian science, as he told me once in a conversation after a lecture on Robert Boyle. The truth and a respect for the given reality which surrounds us and of which we are a part are what drives us on in our scientific work and serve as a check on our frail human pretensions and speculations. Humility and respect will win the day. Pride, particularly scholastic pride in a system of thought, has led to too many pratfalls and in turn stigmatized the gospel. Wanting to take and make his own way also had a down side. Hooykaas frequently did not engage the literature on a particular topic. One often gets the impression that he, and he alone, is the first interpreter of many of the documents and manuscripts he studied.

If there is one hero that shines through Hooykaas's work, it is Blaise Pascal. Hooykaas, like Pascal, abhorred anything that smacked of system building, whether it was the ecclesiastical dogma of theologians or the philosophical systems of the various philosophical schools. And so, he was often fond of quoting Pascal: "The heart has its reasons of which reason knows nothing." Frequently, the little people, the unschooled, served as examples of those who could fell a system with one little word or action. Henry the Navigator's Portuguese sailors, craftsmen, and artisans (like the silversmiths Hooykaas knew in his birthplace of Schoonhoven) were people that moved him. One illustration must suffice:

The Portuguese are the people who first of all opened new vistas for Europe in a concrete manner. Not the Copernican world picture was the starting-point of the scientific revolution, but the hard fact, discovered by the intrepid Portuguese seafarers, that the habitable earth was much greater than ancient and medieval philosophy had deemed possible.7

I also vividly recall his reaction to Walter Thorson's lectures at the 1985 RSCF/ASA meeting exploring the significance of Michael Polanyi's thought for scientific practice. "Why make things so complicated in developing a science? Just do it." A Christian science? That is a chimera best left to rest. "If ... were to try to build a `Christian' science, we should be acting like a man who hunts for his spectacles while they are on his nose. Modern science and technology to a great extent are fruits of Christianity."8

Hooykaas could also deflate the vanity of those in authority. He took ministers and theologians to task in his article, "Dominees en Evolutie" (Ministers and Evolution), for not allowing believing scientists to speak to the issues surrounding evolution in a 1949 Reformed Ecumenical Synod report. Don't they believe in the priesthood of all believers? Aren't believing scientists able to judge and speak to these issues? Don't the theologians remember Calvin's principle of accommodation? Are they trying to repeat the mistake of creating a Mosaic science, i.e., basing a science on the Scriptures? The questions raised form a litany of concerns which Hooykaas continually raised in his publications.9

The larger issue that Hooykaas struggled with was the issue of freedom, a free science or philosophia libera.

The larger issue that Hooykaas struggled with was the issue of freedom, a free science or philosophia libera. As he put it: "The spirit of the Reformation and the spirit of true science have much in common, it is the spirit of liberty through submission to a divine revelation ..."10 It entails a freedom from systems theological and philosophical.

[T]he philosophia libera is no elaborate system, not even an elaborate Christian system, which takes away from us the duty of thinking things out for ourselves. It is the freedom of the children of God, who have found the Philosopher's Stone: the Stone which the builders of philosophy rejected.11

But a freedom to do what? If, in fact, Hooykaas wishes to advance a free science unburdened and unhindered by philosophical and theological systems, then what is the positive relationship between religion as lived and acted on and the scientific enterprise? How does, or should, a Christian view of the world and science intersect? Could there not be a Christian philosophy that might encourage scientific development and provide categories, however tentative, that reflect ontological states of affairs? By restricting theology to Scripture, as Hooykaas tended to do, doesn't religion become in a sense emasculated or restricted to certain arenas? Is a Christian philosophy even possible? Hooykaas's answer seems to be, "No."12 He prefers to be a step-child of the Reformation on this point or at least extremely dubious about its possibility.

In a number of his more philosophical pieces, Hooykaas argued for a rational empiricism.13 One almost sees Francis Bacon's images in this phrase: not the ant (the empiricist) nor the spider (the rationalist), but the bee (rational empiricist) collecting nectar with purpose and cunning. On reflection, his argument for rational empiricism often made his own position appear to carry a positivistic stain. His appeal to facts, quoting T.H. Huxley and Bacon at length, often appeared to be less than self-critical and his tracing of scientific concepts frequently lacked contextualization. No sustained inquiry into the social context of scientific claims (or truth) are to be found in Hooykaas. In his lengthy analysis of Teilhardism, one finds this typical quote:

[T]he founders of modern science strove for a methodological separation of science and religion. With Kepler, (a devout christian), astronomy was made independent of Bible texts, but metaphysical notions still intervened in his method; with Pascal and Boyle, (both apologists of christianity), this separation has become complete. In their scientific work one does not find a word about religion, although their strictly rational-empirical method certainly formed an organic unity with their christian faith.14

Hooykaas, therefore, argued for a methodological, but not an ontological separation of religion and science. The troubling phrase "organic unity" was never explicated in any great detail. He once described this interrelationship between general revelation and scriptural revelation as one of independence: "Christian faith acknowledges two independent sources of revelation: Scripture and Nature."15 But true to form, there never was a systematic analysis of this persistent question.

 Hooykaas...argued for a methodological, but not an ontological separation of religion and science.

On the other hand, the quiet confidence that good, realistic, and humble science is intrinsically Christian, that one can "cleanly" separate the methodological from the ontological, also harbors a danger. How does one stem the tide against what Hooykaas took to be a rising evolutionism? What philosophical weapons, besides his persistent appeal to be humble before the data, could one use if someone was convinced that the weight of the evidence indicated that an extensive evolutionary development had in fact occurred? These issues, the increasing politicization of the university, and the "contextualization of science" movements of the day were difficult ones for him to come to grips with. I suspect he became increasingly isolated on these questions.


Among the many contributions Hooykaas made to the history of science, I think three stand out as signposts of his diverse interests and breadth of knowledge: (1) the historiographic issues tackled in Religion and the Rise of Modern Science; (2) the seminal work done in the history of geology, The Principle of Uniformity and Catastrophism in Geology; and (3) his discovery of a missing work of Rheticus. The first contribution, in particular, with its suggestion of a close causal link between Christianity (specifically the Reformation) and early modern science was met with controversy and question. One only needs to turn to the pages of this journal to read the stinging book review by David Lindberg.16 The most mature and balanced expression of Hooykaas's views on this matter can be found in a recent article entitled, "The Rise of Modern Science: When and Why?" Hooykaas argues:

The rise of modern science has two major causes: firstly, the new natural history and the methodological epistemological changes connected with it; and secondly, the transition from an organistic to a mechanistic view of the world, a change closely connected with experimental philosophy and the contribution made to it by engineers, physicians, alchemists, cartographers, pilots and instrument makers.17

In this article, there are many references to much of his previous work, but again Hooykaas has no real engagement with historians who hold differing viewpoints.18

The seminal work done in the history of geology, The Principle of Uniformity and Catastrophism in Geology, was path-breaking.

The geology work was path-breaking. As Martin Rudwick, a leading historian of science and geology, and eventually Hooykaas's successor at the Free University, described it:

When this work [on `The Principle of Uniformity'] was published...the study of the history of geology was still in a primitive state. Professor Hooykaas put it on a new basis, by emphasizing the reasonableness and scientific value of those who had criticized Lyell's geological arguments. Previously, these opponents had been virtually dismissed, because their scientific arguments had clearly been related to religious concerns. Characteristically, Professor Hooykaas's freedom from their anti-religious historical prejudice made it possible for him to re-assess the value of Lyell's work, and that of these other scientists, more objectively.19

In 1984 Hooykaas published a translation of a missing work, "Treatise on Holy Scripture and the Motion of the Earth," by G.J. Rheticus (1514-1576), an assistant of Copernicus. Hooykaas was able to recognize a quotation (long attributed to Rheticus but never properly identified) in a leaflet bound in a collection of seventeenth century texts.20 In fact, Hooykaas always had a keen interest in how scientists and theologians reflected on the relationship of science and Scripture. In particular, his analysis of John Calvin's position of not reading Greek astronomy into the Scriptures, but rather arguing that the Bible is a book accessible to everyone and that therefore Moses "adapted his writing to common usage" was one he repeated many times.21 In 1955 he had already identified Andrew Dickson White's error in attributing anti-Copernican quotations to Calvin.22

A Quiet Confidence

In many ways, the views of Hooykaas were those of a person confident of the liberating power of the gospel, born to a culture where the engagement of Protestant Christians in cultural pursuits was the air one breathed. Yet he was ever hesitant to be too confident in human constructions and institutions. He enjoyed pricking the balloons of other people's pretensions. He too much relished his role as a gadfly to ever provide a sustained system or argument.

If we want to know what it means to cultivate science in a christian way we should not theorize too much about it, but we ought to state by induction how scientists, who lived consciously out of faith, not only in church but also in the laboratory, saw the relation between science and religion. The history of science demonstrates clearly that respect for empirical facts and methodical independence of theology and philosophy characterized the work of Pascal, Boyle, Newton, Duhem, Faraday, Roozeboom, etc. Consequently they bore fruit, which did not shrivel after a short time, like the speculations of the system-builders.23

He transmitted this confidence to others, particularly to English scientists with a rich sense of their own tradition. Hooykaas was ever active in alerting us to a "cloud of witnesses."24 For that we will ever be in his debt.

Bibliography of Hooykaas's Publications

By way of conclusion, let me give a short (almost) chronological bibliography of Hooykaas's publications in English:

"The discrimination between `natural' and `artificial' substances and the development of the corpuscular theory." Actes du Ve congr╦s International d'Histoire des Sciences Lausanne (Paris, 1948): 113-124.

"The first kinetic theory of gases (1727)." Ibid, 125-129.

"Chemical trichotomy before Paracelsus." Archives Internationale d'Histoire des Sciences 2 (1949): 1063-1074.

"The experimental origin of chemical atomic and molecular theory before Boyle." Chymia: Annual Studies in the History of Chemistry 2 (1949): 65-80.

"Science, materialism, and christianity." Free University Quarterly (FUQ) 1 (1950): 49-62.

"Science and religion in the seventeenth century." FUQ 1 (1951): 169-183.

"Torbern Bergman's crystal theory." Lychnos (1952): 21-54.

"Pascal, his science and his religion." FUQ 2 (1952): 106-137.

"Science and theology in the middle ages." FUQ 3 (1954): 77-163.

"Science and theology." FUQ 3 (1955): 205-211.

"Thomas Digges' Puritanism." Archives Internationale d'Histoire des Sciences 8 (1955): 145-159.

"Science and Reformation." Journal of World History 3 (1956): 109-139.

"The principle of uniformity in geology, biology, and theology." Transactions of Victoria Institute of Great Britain (1956): 101-116.

"Philosophia Libera: Christian Faith and the Freedom of Science." (London: Tyndale Press, 1957).

"The concepts of `individual' and `species' in chemistry." Centaurus 5 (1958): 307-322.

"A christian basis for scientific and technological education?" In Technology and Purpose in Higher Education (London: British Council of Churches, 1959).

Natural Law and Divine Miracle: A historical-critical study of the Principle of Uniformity in Geology, Biology and Theology (Leiden: E.J. Brill, 1959). Second impression as The Principle of Uniformity in Geology, Biology and Theology (Leiden: E.J. Brill, 1963).

"The Historiography of Culture, Science and Learning in Modern Poland." FUQ 6 (1959): 221-244.

The Christian Approach in Teaching Science. (London: Tyndale Press, 1960).

"A New Responsibility in a Scientific Age." FUQ 8 (1961): 78-97.

"Teilhardism." FUQ 9 (1963): 1-17, 58-83.

"The Portuguese Discoveries and the Rise of Modern Science." Boletim da Academia Internacional da Cultura Portuguesa 2 (1966): 87-107.

"Geological uniformitarianism and evolution." Archives Internationale d'Histoire des Sciences 11 (1966): 3-19.

"A new illustration of the Huttonian theory." Atlas (News Supplement of Earth-Science Review) 3 (1967): 177-179.

Dictionary of Scientific Biography, C.C. Gillispie, editor (New York: C. Scribner's Sons, 1970-1980).

"Isaac Beeckman." Vol. I (1970): 566-568.

"Ren╚-Just HaŞy." Vol. VI (1972): 178-183.

"Jean-Baptiste Rom╚ de l'Isle." Vol. XI (1975): 520-524.

"Historiography of science, its aims and methods." Organon 7 (1970): 37-49.

Catastrophism in Geology: it's scientific character in relation to actualism and uniformitarianism (Amsterdam: North-Holland Publishing Co., 1970). Also in Philosophy of Geohistory: 1785-1970. Vol. 13: 310-356, Benchmark Papers in Geology Series (Stroudsburg, PA: Dowden, Hutchinson and Ross, Inc., 1975).

Religion and the Rise of Modern Science (Grand Rapids: Eerdmans, 1972).

"The Impact of the Copernican Transformation." (Milton Keynes: The Open University Press, 1974) Amst. 283, Unit 2, 51-86.

"Puritanism and Science." Ibid., Unit 6, 5-32.

"Genesis and Geology." Ibid., Unit 11, 55-79.

"Nature and History." Ibid., Unit 15, 5-29.

"Calvin and Copernicus," Organon 10 (1974): 139-148.

"Humanism and the Voyages of Discovery in 16th Century Portuguese Science and Letters." Mededelingen der Koninklijke Nederlanse Akademie van Wetenschappen, Afdeling Letterkunde, Nieuwe Reeks Deel 42, no. 4, 1979.

"Pitfalls in the Historiography of Geological Sciences." Histoire et Nature 19/20 (1983): 21-34.

Selected Studies in History of Science (Coimbra: Por ordem da Universidade, 1983).

G.J. Rheticus': Treatise on Holy Scripture and the Motion of the Earth (Amsterdam: North-Holland Publishing Co., 1984).

"The Rise of Modern Science: When and Why?" British Journal for the History of Science, 20 (1987): 453-473.



1No references to Hooykaas's work, for example, are found in a two-volume work dedicated to Geloof en Natuurwetenschap [Faith and Science] (s' Gravenhage: Boekencentrum, 1967) despite a lengthy discussion of the Foster thesis and several sections devoted to history of science replete with appeals to Butterfield, von Weizacker, Holton, etc. A recent book by H. Floris Cohen, a Dutch historian of science, entitled The Scientific Revolution: A Historiographical Inquiry (Chicago: University of Chicago Press, 1994) finally does justice to Hooykaas's contributions.

2These personal recollections are partially based on my attending Hooykaas's lectures for two years (1967-1969) at the Free University of Amsterdam. Also see the recent article by Oliver R.Barclay, "Obituary: Professor Reijer Hooykaas." Science and Christian Belief 6 (1994): 129-132.

3For a good overview of the practice of history of science in the Netherlands see the article by H.A.M. Snelders, "History of Science Today, 2. History of Science in the Netherlands." British Journal for the History of Science 20 (1987): 343-348.

4Capita Selecta uit het werk van Professor Dr. R. Hooykaas (Utrecht: Institute for the History of the Natural Sciences, 1976) has a relatively complete bibliography through 1976, and has good biographical information.

5The Pascal article was translated into English and appeared in the Free University Quarterly of 1952. H. Floris Cohen has his own translation of this article published in 1990 as "Pascal: His Science and His Religion." Tractrix: Yearbook for the History of Science, Medicine, Technology and Mathematics 1 (1990) 115-139. The Boyle study of 126 pages, Robert Boyle: Een Studie over Naturwetenschap en Christendom (Loosduinen: Kleijwegt, 1942) has recently been translated by Harry Van Dyke of Redeemer College as Robert Boyle: A Study in Science and Christian Faith and will be published under the auspices of its Pascal Centre.

6Hooykaas was also a member of a number of European scientific societies and holds an honorary doctors degree from the University of Coimbra in Portugal.

7"The History of Portuguese Culture." Free University Quarterly 7 (1960): 211.

8The Christian Approach in Teaching Science (London: The Tyndale Press, 1960): 12. Emphasis in the original. In a later article, "A New Responsibility in a Scientific Age." Free University Quarterly 8 (1961): 95, he states: "Thus there is no necessity to christianize science: this has already happened. We may consider it a product of the human mind which has been enabled to find its right method and its highest purity by being christianized in the 17th century. In spite of the then following dechristianization of much of Western thought, the basis and method have remained the same."

9"Dominees en Evolutie." [Ministers and Evolution], Bezinning-Gereformeerd Maandblad tot Bewaring en Bevordering van het Christelijk Leven 5 (1950): 74-88.

10Philosophia Libera: Christian Faith and the Freedom of Science (London: The Tyndale Press, 1957): 23

11Ibid, 24. Emphasis in the original.

12"Is een christelijke philosophie mogelijk?" [Is a Christian Philosophy Possible?] Vox Theologica 19 (1948): 48-53.

13See, for example, "De Baconiaanse traditie in de natuurwetenschap," Algemeen Nederlands Tijdschrift voor Wijsbegeerte en Psychologie 53 (1961) 181-201, in which the Baconian tradition is characterized as "the proclamation of rational empiricism, namely experimental science founded on experience in contrast to rationalism and traditionalism," 181.

14"Teilhardism, Its Predecessors, Adherents, and Critics." Free University Quarterly 9 (1963): 59.

15"Science, Materialism, and Christianity." Free University Quarterly 1 (1950): 60.

16David Lindberg, review of Religion and the Rise of Modern Science, in Journal of the American Scientific Affiliation (December 1974): 176-178. Also see the subsequent exchange between D.M. MacKay and Lindberg: JASA (September 1975): 141 and (March 1976): 48.

17"The Rise of Modern Science: When and Why?" British Journal for the History of Science 20 (1987): 471.

18For a thorough and balanced presentation of the historiographical interpretations of the `Scientific Revolution' see H. Floris Cohen's book (fn. # 1). For a recent analysis of the Foster thesis see Edward B. Davis, "Christianity and Early Modern Science: The Foster Thesis Reconsidered," a paper presented at a recent conference on "The Evangelical Engagement with Science," sponsored by the Institute for the Study of American Evangelicals, Wheaton College, Wheaton, IL (March 30-April 1, 1995).

19M.J.S. Rudwick, "The History of the Natural Sciences as Cultural History," Inaugural lecture at the Vrije Universiteit, Amsterdam, (23 May 1975): 13. Also see Rudwick's comments in "Historical Analogies in the Geological Work of Charles Lyell." in Symposium: Hooykaas and the History of Science (Utrecht: Utrecht State University, 1977): 89.

20G.J. Rheticus': Treatise on Holy Scripture and the Motion of the Earth (Amsterdam: North-Holland Publishing Co., 1984).

21Religion and the Rise of Modern Science (Grand Rapids: Eerdmans, 1972): 117-122, 154.

22"Thomas Digges' Puritanism." Archives Internationale d'Histoire des Sciences 8 (1955): 151.

23"Science, Materialism and Christianity." Free University Quarterly 1 (1950): 61-62.

24"Hendrik Willem Bakhuis Roozeboom (1854-1907): Grondlegger der Phasenleer." Geloof en Wetenschap 53 (1955): 77.