Newton

and the Netherlands

How Isaac Newton was Fashioned
in the Dutch Republic

Edited by Eric Jorink and Ad Maas

Leiden University Press

8

NEWTON AND THE NETHERLANDS

vant to Newton's success. Drawing on the recent trend in the history of science for concepts such as
the 'circulation of knowledge', and the focus on the processes of reception, adaptation and
dissemination, we will argue that 'Newtonianism' in the Dutch context was not a sta- ble, coherent
system, originating in Britain and waiting to be imple- mented on the Continent, but a philosophical
construction, adapted to local problems and circumstances. The dissemination of Newton was a
many-sided and complex process, in which natural philosophy, religious and cultural factors,
propaganda and practical concerns, and personal benefits, fears and preferences interacted in a
fascinating

manner.

As this book shows, the 'Newtonianism' constructed by Dutch natu- ral philosophers appears to be
anything but a fixed and clearly defined set of scientific concepts. Many scholars who have been
labeled straightforwardly as 'Newtonians', in practice did not embrace New- ton's natural philosophy
completely. Actually, the Dutch 'Newtonians' mostly used Newton's ideas in a selective or even
defective manner, and were far from dogmatic in their adherence to his work. Moreover, what was
understood by 'Newtonianism' changed in the course of time. Studying Newtonianism, therefore, is
like looking at Dutch fog: it is omnipresent, but intangible as well, it often conceals more than it
reveals and at short distances it seems to disappear altogether. It is no surprise that many of the
authors in this book are intrigued by the 'foggy', intangible character of Dutch Newtonianism.

In the first chapter Eric Jorink and Huib Zuidervaart present an overview of the colorful rise of Dutch
'Newtonianism', and the way the man himself was put on the map, as well as on the market. As they
show, Dutch 'Newtonianism' was a label, an intellectual construction, to a large extent molded by an
already existing tradition of empirical research and by a Protestant natural theology which gave the
study of nature a strong religious connotation. Newton's natural philosophy was adopted to solve
pressing religious and philosophical concerns of Dutch culture, particularly as an antidote to the
'blasphemous' ideas of Spinoza. In the second half of the eighteenth century an increasing
terminological vagueness became apparent. 'Newtonianism' became interchangeable with
experimental philosophy, 'physico-theology' and natural theology, all of which roughly described the
same set of ideas, values and practices. As their research suggests, the sudden success of Newton in
the Dutch Republic after the publication of the
INTRODUCTION

second edition of the Principia in 1713, and the subsequent pirated Amsterdam edition, could be
seen as the result of a conscious strategy of philosophers and publishers.

A particularly penetrating insight into the selective way in which Newton's ideas were adopted is
provided by Fokko Jan Dijksterhuis in chapter 6. His study focusses on the Opticks, Newton's book
about his optical experiments and views (first published in 1704). The reception in the United
Provinces of this book, which, unlike the Principia, has little to say on worldviews and religion,
provides a revealing look into the practical use of Newton's work. The polymath Lambert ten Kate and
the instrument maker and lecturer Daniel Fahrenheit, two well- known 'Newtonians' who became
familiar with the Opticks, largely ignored Newton's central claims and freely picked out the elements
they could use. For Fahrenheit the Opticks proved useful for his pur- suits in telescope making, while
Ten Kate even aimed to correct some elements of Newton's optics with his own experiments,
because they did not fit his own theories. Both were largely indifferent to Newton's natural
philosophical system. How 'Newtonian', then, were these scholars actually? Dijksterhuis ends his
article by calling into question the usefulness of the term 'Newtonianism', which he considerers 'too
ambiguous, to illuminate historical developments". "To put it briefly', he concludes, "Newtonianism"
is not a fruitful category for doing his- tory of science'.

Another chapter that discusses the nature of Dutch 'Newtonianism' is the analysis of its intellectual
dimension by Rienk Vermij (chapter 7). While emphasizing the heterogeneous character of the Dutch
Newto- nians, Vermij identifies a common project, namely 'defining the rela- tion between God and
nature in a way which answered both scientific and religious demands'. This 'project' had an
important impact on the interpretation and perception of Newton's ideas by Dutch scholars.

While in the seventeenth century nature was increasingly consid- ered in terms and concepts
adapted from natural philosophy and geometry, there was some unease about its consequences for
tradi- tional religious views. The presumption that the universe was direct- ed by a set of eternal and
immutable laws of nature could lead to a deterministic worldview in which God's role was
marginalized. What was ultimately at stake, Vermij argues, were not philosophical matters as such,
but the authority of the Bible. How could the supernatural events of the Scripture be brought in
accordance with new scientific
10

NEWTON AND THE NETHERLANDS

developments? From Newton's natural philosophy a worldview could be derived in which the world
depended directly on God's benevo- lence. Vermij argues that this worldview was instrumental in
achiev- ing a broad consensus that arose in the eighteenth-century Dutch Republic: the miracles and
mysteries of the Bible remained outside the scope of scientific interpretations and, on the other
hand, super- natural events were no longer considered credible in daily life.

Henri Krop establishes (chapter 9) that in the course of the eight- eenth century a 'Newtonian'
philosophical system was taught at the Dutch universities, which included not only natural
philosophy, but also a logic and a metaphysics. The rise of such a comprehensive aca- demic
Newtonianism was unique to the Netherlands, and was distinct from the popular branch' of
Newtonianism, which in particular found expression in physico-theological writings.

Krop focuses mainly on the late eighteenth-century writings of the then influential natural
philosopher Jean Henri van Swinden, profes- sor at Franeker and Amsterdam. Van Swinden employed
in his meta- physics a Cartesian dualism of the bodily and the immaterial world. The latter should be
investigated by mathematics and metaphysics, the former by observations. Thus, Van Swinden
insisted on a sound combination of rationalism and empiricism for investigating nature, which
according to him had a God-given, all-encompassing, teleolog ical order. According to Van Swinden's
interpretation, it was Newton who had managed to combine the deductive and the inductive meth-
od in a fruitful manner.

This book maintains that even the three Leiden professors who became the figureheads of
Newtonianism throughout Europe - Her- man Boerhaave, Willem Jacob 's Gravesande and Petrus van
Mus- schenbroek - cannot simply be regarded as 'dogmatic' Newtonians. Rina Knoeff elaborates in
chapter 3 that Herman Boerhaave - the first who openly supported Newton in an academic oration -
hardly used Newton's mechanical philosophy at all in his medical work. At the beginning of his career,
Boerhaave applied Newton rhetorically to criticize the method of Descartes, as an example of a sound
use of mathematics in the study of nature. As he later in his career became increasingly skeptical
about the usefulness of the mechanical method for medicine, he no longer referred to the
'mathematical' Newton, but rather to his chemistry, to the experimental approach of the Opticks.
Knoeff concludes that although Boerhaave was inspired by Newtoni-

an methods, he was at the same time critical about Newton's results. Boerhaave's turn to chemistry,
 with its emphasis on non-mechanical powers in the body, even caused a decline of Newtonian
medicine from the 1740s onwards. Nor did Willem Jacob 's Gravesande, the most influential dissemi-
nator of Newton's ideas in the first decades of the eighteenth century, always follow in the steps of
his master. As Ad Maas argues (chapter 4), 's Gravesande decided to spend his life on popularizing
Newton's natural philosophy not only because of its supreme intellectual qual- ities but also because
it coincided with 's Gravesande's personal pref- erences and furthered his career. Maas suggests that
by dissociating Newton's natural philosophy from the metaphysical and theological concerns that
had worried Newton's early Dutch followers, 's Grave- sande paved the way for the introduction of
Newton's natural philo- sophical system into the Dutch academic curriculum. Kees de Pater suggests
in chapter 5 that in the case of Petrus van Musschenbroek, too, there is a marked discrepancy
between rhetoric and scientific practice. Although Van Musschenbroek portrays him- self as a
wholehearted follower of Newton, he deploys in his research a rather individual interpretation of
what Newtonianism concerns, focusing especially on its empirical aspect. As De Pater concludes, the
limits of this approach became clearly visible in Van Musschen- broek's research, which tended to
result in a rather pointless piling up of experimental data. On the other hand, Van Musschenbroek
was not always able to abstain from 'feigning hypotheses' when speculating about the nature of
matter and forces. Two of the contributions to this volume reach beyond the borders of the Dutch
Republic. The tragic central figure of Jordy Geerling's article (chapter 8), Johann Konrad Franz von
Hatzfeld, was a German lackey, who spent some years in England, but also stayed for a while in the
Republic, the refuge for a number of European freethinkers. In The Hague, Hatzfeld published his La
découverte de la vérité (1745), which contained a ferocious attack on Newton's natural philosophy.
Hatzfeld was condemned for the opinions he expressed in his book, not for his attack on Newton, but
for his radical religious and political views. His books were burnt and Hatzfeld was banished.
Hatzfeld's story is a case study in how personal and social factors could lead to radicalization. By
following Hatzfeld's footsteps, Geer- lings opens a fascinating panorama of marginal intellectuals
who 11 INTRODUCTION
12

NEWTON AND THE NETHERLANDS N

built perpetua mobilia and considered fermentation to be the driving force of the universe, and of
radical Wolfians, Aletophilen, Freemasons and to be sure - anti-Newtonians.

In Rob Iliffe's article (chapter 2), the somewhat unfathomable figure of Nicolas Fatio de Duiller leads
us over the border of the United Prov- inces. For a while Fatio held a unique position as a close
collaborator of both Christiaan Huygens and Isaac Newton, and seemed to be on the brink of joining
the ranks of the most prominent mathematicians and natural philosophers. For a brief period of time
he seems even to have obtained Newton's assent for taking care of a revised, second edition of the
Principia, in which Fatio would incorporate his own theory of gravity. However, the close association
with Newton and Huygens also made it difficult for him to develop his own reputation in the commu-
nity of natural philosophers, and after the first years of the 1690s, he gradually faded from view.

In contrast to the other articles in this volume, Iliffe's contribution addresses not the dissemination,
but rather the genesis of Newton's ideas. His story describes the intriguing period directly after the
pub- lication of the Principia, in which its contents were widely discussed and its main conclusions
had not yet taken shape as the indisputable laws of mechanics. This was also the period in which the
controversy between Newton and Leibniz about differential calculus started. In both developments,
Fatio and Huygens played a significant role. Also in contrast to the other contributions in this book,
we see in Iliffe's chapter the 'real' Newton in action. It is here that we finally meet a person who can
safely be considered as a Newtonian..

Between the English and the Dutch coast lies the North Sea. It is often from this direction that dense
fog penetrates the Netherlands. Sometimes, in the patches of fog that move over the country, one
can recognize, with a little imagination, the figure of Isaac Newton, chas- ing the ghost of Spinoza.

Note

1 We would like to thank Pete Langman and Nadine Akkerman, who came up with the idea for this
conference.
"The Miracle of Our Time'

How Isaac Newton was fashioned in

the Netherlands

ERIC JORINK AND HUIB ZUIDERVAART

13

THE MIRACLE OF OUR TIME'

Introduction

It has more or less become a truism that the Dutch Republic played an important, not to say crucial,
role in the spread of 'Newtonianism' in Europe during the early eighteenth century.' As Klaas van
Berkel has written:

It is partly or even mainly thanks to intellectual circles in the

Dutch Republic that Newton's ideas were after all accepted in the rest of Europe; Dutch scientists and
Dutch manuals were respon- sible for the spread of Newtonianism through Europe. For once, the
Netherlands was indeed the pivot of intellectual Europe.

It is well known that in 1715 Herman Boerhaave (1668-1738), by far the most famous professor of the
Dutch Republic, was the first academic to speak in public strongly in favour of Newton, calling him
'the mir- acle of our time' and 'the Prince of Geometricians'. In the very same year, the
mathematician and burgomaster Bernard Nieuwentijt (1654- 1718) published his Het regt gebruik der
wereldbeschouwing (The Reli- gious Philosopher: Or, the Right Use of Contemplating the Works of
the Creator), a work which would become extremely popular, both in the Netherlands and abroad,
and which made important references to Newton. Het regt gebruik contributed much to the
popularity of the experimental natural philosophy, so characteristic of eighteenth-cen- tury Dutch
culture. Moreover, in 1715 a young journalist and lawyer named Willem Jacob 's Gravesande (1688-
1742), travelled to London
14

NEWTON AND THE NETHERLANDS

as secretary to the Dutch ambassador. Here, he attended John Desa- guliers' lectures, made
acquaintance with Newton and was elected a Fellow of the Royal Society. Having tasted English
'Newtonianism', in 1717 's Gravesande was appointed professor of mathematics and astronomy at
the famous University of Leiden. As such, he was in the right position to preach the gospel of Newton.
Three years later, in 1720, 's Gravesande published his well-known Physices elementa math- ematica,
experimentis confirmata: sive introductio ad philosophiam Newtonianam. In this work, 's Gravesande
gave a systematic account of 'Newtonian' physics as he saw it. The work was an instant success, going
through many editions, translations and reprints. It was through 's Gravesande's handbook that his
'Newtonianism' was exported to Britain. 's Gravesande acquired such a reputation as an apostle of
Newton, that an ambitious young Voltaire came to Leiden in 1735 to follow the professor's lectures.
Voltaire, already fascinated by Newton and his natural philosophy, was by then working on his own
Élémens de la philosophie de Newton, to be published in Amsterdam in 1738.

For a long time, the sudden popularity of Newton in the Dutch Republic seemed to need no
explanation: 'Newtonianism' was seen as the logical step, from 'Aristotelianism', via 'Cartesianism',
towards modern science. From this perspective, the introduction in 1715-1717 of Newtonian physics
into the academic curriculum was inevitable. In this article, we will argue that 'Newtonianism' is a
rather problem- atic term in the Dutch context. The success of Newton's conception of nature was
not predetermined, nor was it self-evident. The philosoph- ical concept named after the great
Englishman was an elaboration of an already existing tradition of empirical research, founded in Leid-
en in the early seventeenth century: Newton, as he was fashioned by the Dutch, fitted nicely into this
tradition. In 1715, in the context of the Protestant Dutch Republic, Newton was modelled into a
useful icon, to combat the clergy's growing fear of extreme rationalism. The emer- gence of Dutch
'Newtonianism', and the popularity of Newton himself, can only be understood in the light of the
philosophical and theologi- cal developments of the late seventeenth century. For that reason we will
present an outline of these developments. 'Newtonianism' in the Dutch context was not an imported
coherent system, waiting to be implemented, but a philosophical - and to a certain extent social -
construction, created for and adapted to specific local problems and circumstances.
15

THE MIRACLE OF OUR TIME

Scientific culture in the Dutch Republic

In the mid-seventeenth century the young Dutch Republic had become one of the most flourishing
countries of early modern Europe, not only in terms of commerce but also in terms of art, learning,
science and technology. During the Dutch Revolt many Protestants had fled the Catholic South and
started a new life in the North. This had far-reach- ing consequences: while intellectual life in the
sixteenth century had been concentrated in the Southern Netherlands, especially in Antwerp and
Louvain, the emphasis now shifted to the North. The Amsterdam region became a particular hub of
trade, traffic and technology, draw- ing not only Protestant refugees from the Spanish Netherlands,
but also many Scandinavians and Germans who escaped the Thirty Years' War, as well as Sephardic
Jews and (later in the seventeenth century) French Huguenots. This mixture of persons, ideas and
goods provided a fertile soil for the exchange and creation of knowledge. In a recent volume, Sven
Dupré and Christoph Lüthy state:

the 'circulation of knowledge' was perhaps nowhere as intense as in the early modern Low Countries,
and this had to do as much with the circulation of scholars which was, in the Carrefour de la
République des Lettres, particularly lively, as with the extraordinary nodal points that cities like [first]
Ant- werp and [later] Amsterdam represented in the international exchange of goods, news, and
skills."

Lacking an older scholastic tradition, the newly founded Protestant universities of the North,
especially those of Leiden (established in 1575) and Utrecht (established in 1636) could be more
innovative than most of the older universities. They attracted many students, pro- fessors and visitors
from abroad. To give a few examples: the Leiden medical faculty improved upon the new approach
introduced by the Italian universities in the sixteenth century. A theatrum anatomicum was
established in 1590, as well as a hortus botanicus in 1594, both sup- ported by huge collections of
curiosities. In 1634 the university found- ed an astronomical observatory (the first of its kind in
Europe) and clinical teaching started two years later, becoming famous through- out Europe during
the professorship of the iatro-chemist Francis de le Boë Sylvius (1614-1672). Up to the era of
Boerhaave (1668-1738), Leiden's medical faculty was considered the best in Europe, attracting
NEWTON AND THE NETHERLANDS

many students from all over the Continent. An empirical approach towards the investigation of nature
thus lay deeply rooted in the aca- demic curriculum.

An important factor was the religious context of scientific dis- course and practice. The Northern
Netherlands was a striking exam- ple of religious pluriformity. The most powerful denomination was
the Reformed (Gereformeerde or Contra-remonstrant) Church, which was, however, not the largest in
terms of membership; it contained several currents, ranging from the Puritan-like orthodoxy of the
influ- ential Utrecht professor of theology Gisbertus Voetius (1589-1676), to the more liberal
followers of his Leiden colleague Johannes Cocceius (1603-1669). Although the Reformed Church was
never to acquire the status of a state religion in the young Republic, and was in fact just one of the
many denominations in the religious landscape, it was priv- ileged, and those who held public office
(including university profes- sors) were required to subscribe to its doctrines. Besides the Reformed
Church there existed a stunning variety of denominations, such as the Remonstrants, Mennonites,
Huguenots, Lutherans, Jews, and all kinds of sects, such as Collegiants, Millenarians, Quakers,
Labadists and Borelists. Moreover, there was a large Catholic minority. Two things are of importance
here: first, that the religious pluriformity of the North stimulated theological, philosophical and
scientific debates; and, second, that the largely Protestant culture of the North had a strong
undercurrent of natural theology which, in turn, encouraged an open eye towards God's creation. The
notion of the Book of Nature, that is to say, the idea that Creation was the second revelation of God
next to the Bible, was of great influence. Important in this respect is the so-called 'Belgic Confession'
of 1561, a document that formed the basis of the orthodox Reformed Church in the Dutch Republic.
Article II, in the edition of 1619, runs:

We know him [God] by two means. First, by the creation, preservation, and government of the
universe, since that universe is before our eyes like a beautiful book in which all creatures, great and
small, are as letters to make us ponder the invisible things of God: his eternal power and his divinity,
as the Apostle Paul says in Romans 1:20. All these things are enough to convict men and to leave
them without excuse. Second, he makes himself known to us more openly by his holy and
17

THE MIRACLE OF OUR TIME

divine word, as much as we need in this life, for his glory and for the salvation of his own."

Since nature was God's creation, the study of nature was an enterprise with strong religious
connotations. The order of nature as a whole, as well as the existence of each and every individual
creature, was seen as the manifestation of God, the almighty Architect. This principle was invoked by
those who advocated empiricism.

Of similar importance in this respect was René Descartes (1596- 1650), who lived in the Dutch
Republic from 1628 to 1649. His revo- lutionary new philosophy, as outlined in the Discours de la
méthode (published in Leiden in 1637), was embraced from the start by some university professors
from Utrecht and Leiden." To Dutch profes- sors of the (higher) faculty of medicine and the (lower,
propaedeu- tic) faculty of philosophy, Descartes' rationalism and his geometrical, mechanistic
approach towards nature, seemed an all-encompassing alternative to the increasingly problematic
philosophy of Aristotle. It was within a Cartesian context that new hypotheses, such as Nico- laus
Copernicus' heliocentric theory (De revolutionibus orbium coeles- tium, 1543) and William Harvey's
theory of the circulation of the blood (De motu cordis, 1628) were debated and after fierce
opposition by orthodox theologians - gradually accepted." The work of Christiaan Huygens (1629-
1695), by far the greatest mathematician and nat- ural philosopher of the Dutch Golden Age, is
unthinkable without Descartes (although he developed an increasingly sceptical attitude towards the
Frenchman's work).12

However, in the eyes of orthodox theologians and philosophers, Descartes' philosophy threatened to
destroy old certainties. Descartes not only offered a new natural philosophy, but a new epistemology
and metaphysics as well. Cartesian doubt seemed to open the gate to scepticism and even to
atheism. Cartesian physics seemed to presup- pose God as a distant engineer and, probably worst of
all, Cartesian rationalism implied that all of God's creation could be explained and understood. In
1642, the orthodox party, led by Voetius, started a long and bitter campaign against the New
Philosophy. Although Cartesian- ism was twice officially banned from the Universities of Leiden and
Utrecht, it was never threatened seriously. The universities' curators tried to effect a peaceful
coexistence between the two sides, alternate- ly appointing Cartesians and Aristotelians to the chairs
of medicine,
18

NEWTON AND THE NETHERLANDS

philosophy and even theology. Nevertheless, the relations remained strained.

The orthodox Voetians saw their worst nightmare come true, when in 1670 Benedictus Spinoza
(1632-1676) anonymously published his Tractatus theologico-politicus. Spinoza, amongst other
things, drew the Cartesian notion of the immutable laws of nature to its logical conclu- sion: God was
bound by his own laws and the Biblical miracles could thus never have happened. The Bible was not
God's revelation to man, nor the key to nature's secrets, but only the history of a certain tribe in the
Middle East. In the Ethica (published posthumously in 1678), Spinoza advocated at length the
absolute certainties offered by the geometrical method. By now, to the orthodox clergy, rationalism
and mathematics seemed the source of atheism and hence of all evil in the world. The problem was
not only that Spinoza was seen as irreligious, since he postulated that God and Nature were identical
(the notorious Deus sive Natura), but that he claimed his atheistic ideas to be based on absolute
mathematical certainty.

This was what rationalism would inevitably lead to: an attack on the authority of Scripture. Spinoza's
philosophy was abhorred by nearly all of his contemporaries, who were convinced that rationalism
and the geometrical method would inevitably lead to atheism. In the eyes of many Dutchmen,
Spinoza reaped the harvest that Descartes had sown. The Leiden Reformed consistory noted with
disgust that the Opera posthuma 'perhaps since the beginning of the World until the present day [...]
surpasses all others in godlessness and endeavours to do away with all religion and set godlessness
on the throne'. The Leiden city council and the governing body of the university decided that, since
the Opera paved the way for an absolute atheism', the book was to be banned immediately, all copies
sold were to be confiscat- ed and burned, and the owners fined." After ample deliberations, the book
was banned by the States of Holland for containing 'very many profane, blasphemous, and atheistic
propositions'.15

Besides the contents of Spinoza's philosophy, there was also a force at work that can be called the
personal factor. While earlier philoso- phers such as Aristotle, Francis Bacon (1551-1621) and even
Descartes were only vaguely associated with real persons, the memory of the 'most horrible of
atheists', the 'apostate Jew', the 'destroyer of Chris- tianity' remained much alive during the
eighteenth century. Pierre Bayle (1647-1706), 'le philosophe de Rotterdam', included an entry on
19

THE MIRACLE OF OUR TIME"

Spinoza in his famous Dictionaire historique et critique (first edition 1697; in later editions this entry
was expanded), which was immedi- ately issued as a separate treatise in Dutch, Het leeven van B. De
Spi- noza, met eenige aanteekeningen over zyn bedrijf, schriften, en gevoelens (1698).16 On the basis
of thorough research, the Lutheran minister Johannes Colerus (1647-1707) published his short
biography of Spi- noza in 1705." Although both writers vehemently rejected Spinoza's system, they
had to admit that the philosopher had lived like a saint: modest, peaceful, abstemious. This image
was endorsed by Spinoza's correspondence, first published in the banned Opera posthuma (1678),
and available to a wide audience through the translation published in De boekzaal van Europe in
1705. Spinoza really presented the most pressing intellectual problem of the later seventeenth and
early eight- eenth century.18

Newton enters the stage.

It was against this background that Newton entered the Dutch intel- lectual sphere. The first serious
attention given to Newton in the Netherlands followed the publication of 'An Accompt of a New Cata-
dioptrical Telescope' in the Philosophical Transactions of March 1672. Very few Dutchmen were able
to read English at that time, but the invention was also discussed in the Journal des sçavans, an
edition of which was published in Amsterdam in 1673. It was Christiaan Huy- gens who had been
personally responsible for the French analysis. Already in January 1672 Huygens was informed of
Newton's invention, in a letter by Henry Oldenburg (c. 1618-1677), the secretary of the Royal Society.
Huygens immediately informed Jean Gallois, the editor of the Journal des sçavans, of this remarkable
new kind of telescope." Short- ly afterwards, in March 1672, Oldenburg sent Huygens Newton's 'New
Theory about Light and Colours', which was published in the current issue of the Philosophical
Transactions. 20 Again Huygens gave a positive response. In July 1672 Huygens wrote to Oldenburg
that he appreciated the 'colour hypothesis of Mr. Newton', and although the 'Experimen- tum crucis'
was a bit obscure in its presentation, he understood that it underscored Newton's new optical
theory." Newton's invention and his new theory of light prompted Huygens, a skilled lens-grinder
who had constructed telescopes and discovered the rings of Saturn, to fol- low Newton's work
intensely; it had the same effect on lesser minds.22
20

NEWTON AND THE NETHERLANDS

Dutch reactions to the first edition of Newton's Principia (1687) The publication of Newton's Principia
in 1687 aroused great attention in the Netherlands, but only among a small minority. It is well known
that Huygens received a copy from the author, studied the book inten- sively, and discussed its
contents with Nicolas Fatio de Duillier (1664- 1753). 'I wish to be in Oxford', Huygens wrote to his
brother, 'just to meet Mr. Newton, for I greatly admire the beautiful inventions that I find in the book
he sent me.23 Huygens was much impressed by the book, although he did not subscribe to its main
idea: the theory of universal gravitation. To Huygens, still working within what might be called a
Cartesian framework, the concept seemed to bring back qual- ities such as occult powers and hidden
properties. Newton's theory just seemed 'absurd'.24 Nevertheless, Huygens appreciated the mathe-
matical ingenuity of the Principia, and he recommended the book to the influential Amsterdam
burgomaster Johannes Hudde (1628-1704), one of the very few other Dutchmen able to follow
Newton's calcula- tions.25 As Rob Iliffe describes in this volume, Huygens remained for some years in
close contact with Newton, using Fatio de Duillier as a go-between.

A third important Dutch intellectual to be acquainted with the Principia at a very early stage was the
Leiden professor of philoso- phy Burchardus de Volder (1643-1709).26 De Volder, a close friend of
Huygens and Hudde, personally met Newton as early as 1674, when he visited England. He was much
impressed by Boyle's and Hooke's experiments performed at the Royal Society. Back home in Leiden,
and with the approval as well as the financial support of the Leiden curators, he started a theatrum
physicum in which he used a Boylian air-pump to illustrate his lectures. Leiden University was the first
in Europe to provide such facilities for experimental philosophy. Cam- bridge (where Newton had
lectured from 1669 to 1701) followed in 1707, while Paris had to wait until 1751. But as pioneering as
it was, De Vold- er's initiative fitted neatly into the long-standing empirical tradition in Leiden that
had begun with the hortus botanicus and the theatrum anatomicum. Tellingly, the curators approved
De Volder's request in the hope that 'many students from other universities and academies will be
lured hither' by his often spectacular demonstrations." By way of these demonstrative experiments,
De Volder (and his lesser-known colleague, Wolferd Senguerd, 1646-1724) created a fertile ground for
the blossoming of eighteenth-century experimental physics.
Although De Volder also had the privilege of receiving an author's copy of Newton's Principia, he
never became an advocate for the work's theories. De Volder's experimental method was evidently
inspired by Boyle, not by Newton. Much like his friend Huygens, De Volder admired the mathematical
side of Newton's work, but he only mentioned Newton in passing during his academic career.28

This was not the case in the lectures of the Scotsman Archibald Pit- cairn (1654-1713), a friend and
early follower of Newton, who in 1692 was appointed professor of medicine in Leiden. However, he
left this post within a year. Although it is suggested that Pitcairn had an impact on a number of
Scottish students who had followed his Leiden lec- tures, there is no hard evidence that he gained any
Dutch followers. 29 There are other indications that the Leiden academic commu- nity had little
interest in Newton's book. In 1687 the influential Lei- den bookseller Pieter van der Aa (1659-1733)
received twelve copies of the Principia in commission from Newton's publisher in London, with the
explicit intention of selling them on the Dutch market and at the Frankfurt book fair. But after two
years of prudence Van der Aa returned the seven copies that still remained in stock.30 Through the
purchase of the famous library of Isaac Vossius (1618-1689), Lei- den University acquired a copy of
the Principia as early as 1690, but it took twelve years before the collection could be consulted.31
Even in 1711 the Leiden professor in chemistry, Jacobus le Mort (1650-1718), ridiculed Newton's
concept of universal attraction.32 So before 1715, in academic circles, Newton was admired as a
mathematician, but not as a physicist.

Amsterdam mathematical enthusiasts

As Rienk Vermij has shown, the earliest Dutch admirers of Newton were not to be found among
university professors, but among an infor- mal group of Amsterdam mathematicians in the 1690s.33
In the Dutch Republic, a lively intellectual culture existed, including many informal clubs where
philosophical, religious and scientific ideas were debat- ed. In the mid-seventeenth century most
Dutch cities had a theatrum anatomicum, which not only served for a medical education, but were
also used as cultural convergence points: places where a library was formed, natural history
specimens were collected and intellectual dis- cussion was possible.34 And there were other forms of
intellectual life too. To name a few examples: a group of early followers of Spinoza held

21

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NEWTON AND THE NETHERLANDS

weekly meetings in the 1660s; in the same period the research-oriented Collegium Privatum
Amstelodamense was founded, which focussed on comparative anatomy and included John Locke
(1632-1704) dur- ing his stay in Amsterdam. In the 1690s the Haarlem-based Collegi- um Physicum
discussed problems from the post-Cartesian textbook by Jacques Rohault (1618-1672), performing
experiments and arguing with congenial enthusiasts from elsewhere, such as the Amsterdam
Mennonite merchant Lambert ten Kate Hermansz (1674-1731) and the Rotterdam Quaker Benjamin
Furly (1636-1714).35

The group of Amsterdam mathematicians seemed to have includ- ed a broker named Jacob Makreel,
a Mennonite merchant named Adriaan Verwer (c. 1655-1717), and the physician, mathematician and
regent Bernard Nieuwentijt, who lived in nearby Purmerend.36 The group was interested not only in
mathematics, but in philosophical and religious themes as well. They had many foreign contacts,
includ- ing George Cheyne (1671-1743) and David Gregory (1659-1708), who kept them informed on
British affairs. For example, Nieuwentijt, who was working on infinite series, learned from Gregory
that Newton had already published on this topic (apparently this concerned the pieces included in
John Wallis' Algebra of 1685). In 1694 and 1695 Nieuwen- tijt published two mathematical tracts on
the brand new calculus, the Considerationes and the Analysis infinitorum, in which he rejected
Leibniz's approach to the subject, but praised Newton, referring sev- eral times to lemmas from the
book of 'this illustrious author', iden- tified later on as the Principia.37 So the Amsterdam group
apparently discussed Newton's Principia at an early stage, and one wonders if its members were
among the buyers of the five copies that Van der Aa had sold. Nieuwentijt considered Newton to be
the greatest living mathematician, while Verwer embraced the universal law of gravita- tion.
However, this support for Newton was strongly stimulated by ulterior motives.

The pious Verwer, an active member of the Amsterdam Mennonite congregation Het Lam en de
Toren (The Lamb and the Tower), was typical of the many Dutchmen who sought God outside the
bound- aries defined by the orthodoxy of the Reformed Church.38 Although Verwer as far as we
know had no academic training, he knew Latin, was a skilled mathematician and maritime expert, and
studied his- tory, religion, philosophy and linguistics. He vehemently rejected the Spinozist conception
of God and Nature. Already in 1683, he had
published a refutation of Spinoza's Ethics, namely 't Mom-aensicht der atheistery afgerukt (Atheism
Unmasked). Throughout his life, he con- tinued to seek proof of non-natural and non-material forces
in Crea- tion, which he evidently found in the work of Newton.39 Verwer's copy of the Principia, now
in Utrecht University Library, contains his manu- script notes. In his Inleiding tot de christelyke gods-
geleertheid (Intro- duction to Christian Theology, 1698), Verwer explicitly referred to the Principia to
prove that the elliptical shape of a planet's orbit would be impossible without the interception of a
Governor, who exists outside these things'." Elsewhere in his book, Verwer used Newton's formula for
the inverse square law to give the mathematical proof that 'eternal happiness is proportional to good
works, and inversely proportional to divine grace'.42

Anti-Spinozism was also to become a life-long concern for Nieuwen- tijt, who in 1715 and
(posthumously) in 1720 would publish two books explicitly directed against the 'ungodly
philosopher', namely Het regt gebruik der wereldbeschouwingen, ter overtuiginge van ongodisten en
ongelovigen (translated into English by John Chamberlayne as The Religious Philosopher: Or, the Right
Use of Contemplating the Works of the Creator in 1718) and Gronden van zekerheid [...] ter
wederlegging van Spinoza's denkbeeldig samenstel (Grounds of Certainty [...] Intended to Refute
Spinoza's Imaginary System).

The main objections of Verwer and Nieuwentijt to Spinoza were that he did not believe in God as the
Almighty Creator, but only in blind fate and chance and, moreover, that he undermined Christian faith
by claiming absolute mathematical certainty. Both Verwer and Nieuwentijt sought to do the opposite,
i.e. to strengthen Christianity on the basis of mathematical arguments. And it was here that Newton
was put to use. The Englishman was seen as a brilliant mathematician of unimpeachable conduct. But
more importantly, Newton made a clear distinction between pure and applied mathematics.
Mathemat- ics was essential for the study of nature, but only when mathematical reasoning was
tested by experience could one say that mathematics had anything to do with reality. 43 This was
crucial for Verwer and Nieu- wentijt. In his Gronden van zekerheid the latter used this distinction to
tackle Spinoza's claim to mathematical truth. Moreover, Newton was very clear about the place of
God as the ultimate ruler of the universe. The metaphysical nature of gravity underscored this picture
of Newton as a real Christian mathematician. Newton's work seemed to provide

23

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NEWTON AND THE NETHERLANDS

an uncontested basis for a truly Christian natural philosophy. Newton saved, so to speak, the
mechanical way of reasoning, from the atheistic spell of Descartes and Spinoza.44 Thus, in the wake
of the publication of the first edition of the Principia, a small group in the Netherlands created an
image of Newton which presented him not just as a pious mathematician, but as a philosopher
whose message was relevant to the whole of Christianity. It was these aspects that set the stage for
Newton's later success in the Dutch Republic.45 Without this aura, he would never have been so
influential.

Jean Le Clerc

This pious fashioning of Newton would have been impossible if his anti-Trinitarian tract, An Historical
Account of Two Notable Corrup- tions of Scripture, which he had sent to Locke in the early 1690s, had
been printed by the Amsterdam publisher Jean Le Clerc (1657-1736). This Swiss Huguenot had to flee
from his native Geneva because of his unorthodox ideas and subsequently earned a living in
Amsterdam as a journalist and professor of theology at the Remonstrant seminary. For a few months,
Newton favoured the idea of allowing Le Clerc to pub- lish a Latin or French translation of his
Historical Account, but then he withdrew it.46

As is now well known, Newton spent much of his time on biblical criticism, millenarian prophecies
and alchemy. Only a small circle knew of Newton's heterodox ideas. But in the wake of the Principia,
he seriously considered publishing some of his religious works. In the Historical Account, Newton
argued that the dogma of the holy Trinity had no foundation in Scripture, and that the biblical
passages 1 John 5.7 (the 'Johannine comma') and 1 Timothy 3.16 were corrupt. Le Clerc's copy,
written in Locke's hand, went missing. The work was finally pub- lished in 1754.47 Had Le Clerc
published it in the 1690s, Newton would have had a lifelong reputation among the Dutch for
propagating unor- thodox, if not heretical, ideas, putting him firmly in the camp of free- thinkers and
atheists, with Isaac la Peyrère (1596-1676), Isaac Vossius and Spinoza.48

Le Clerc, who was a personal friend of Verwer, would serve the 'Newtonian case' in other ways. He
edited the Bibliothèque univer- selle, which was the only Dutch-issued journal to publish a review of
Newton's Principia. The review was printed anonymously in 1688, but was in fact written by Locke,
who lived in the Dutch Republic from
1684 to 1688, and would have a notable impact on the intellectual life of the Netherlands.50 Other
Dutch journals, such as Pierre Bayle's Nou- velles de la République des Lettres, completely ignored
the Principia.

Given Locke's review, Le Clerc must have had a basic idea of the Prin- cipia. But like Verwer, he was
rather eclectic. When in 1696 he wrote a textbook on physics, he just repeated the views of several
authors on various subjects, including a brief account of Newton's theory of gravi- ty, which he used
to repudiate the Cartesian vortices, although he still interpreted gravity in a corpuscular way."
Evidently Le Clerc accepted Newton's way of mathematical reasoning, without giving it credit as an
accurate picture of reality.

The Amsterdam scholar would again pay attention to Newton's work after the 1706 Latin edition of
Newton's Opticks, a work whose somewhat neglected reception in the Netherlands is addressed by
Rina Knoeff and Fokko Jan Dijksterhuis in this volume. Le Clerc was one of the few in the Republic to
review the Opticks. It is tempting to see a connection between the enthusiasm for Newton among
the Amsterdam amateurs and the 'Newtonian' edition of Rohault's famous textbook on physics,
issued in 1708 by the Amsterdam pub- lisher Johannes Wolters.52 At first sight Rohault's work was a
manual on Cartesian physics, but in 1696 and again in 1702 - the English Newtonian Samuel Clarke
had produced an edition with very exten- sive notes, adding many references to the Principia. In fact,
before 1713 this annotated Rohault edition was for many scholars the first intro- duction to Newton's
way of physical reasoning.53

During these years Le Clerc's enthusiasm for Newton increased. In 1690, he called Newton 'this great
mathematician' and in 1706 'one of the greatest mathematicians that ever lived'. But he really
became a Newtonian after reading the second edition of the Principia, published in Cambridge in
1713. In a review in his new journal Bibliothèque anci- enne et moderne he called Newton without
reservations 'the greatest mathematician the world has ever seen'.54 According to Le Clerc, it was
Newton who gave the coup de grâce to materialistic and atheistic speculations. As Vermij has noted,
'upon reading the second edition of the Principia Le Clerc apparently came to realize the full impact
of Newton's ideas. In his review he focused mainly on Roger Cotes' pref- ace and on the new
'Scholium', the two additions which were so suc- cessful in giving the highly abstract book a more
philosophical twist. Le Clerc was a sworn enemy of Descartes' materialism and of Spino-

25

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26

NEWTON AND THE NETHERLANDS

za's conception of nature, and now he realized that Newton stipulat- ed that the universe was
governed by a force - gravitation - which could not be explained in any mechanical way. This anti-
materialistic approach was exactly what he needed. The law of universal gravita- tion described with
mathematical precision what happened in the heavens, but its nature was evidently metaphysical. It
therefore pro- vided the ultimate proof of God's existence. In 1715, in the introduction to a series of
reviews of works by other British scholars, like George Cheyne, John Ray and William Derham, Le
Clerc added that Newton's principles:

show that it is impossible that the world has been made, and remains in its present state, by purely
mechanical forces and movements. This leads us to recognise that there is a fully immaterial God,
who is the creator of the world. [...] This is quite different from the principles of Descartes, who
believed that it sufficed for God to have given motion to matter just

once to see everything in the world, or at least everything material, come forth from it.56

For the Dutch scholars Newton had published the second edition of his book at the right time. He
entered the stage at a moment when the discontent with Cartesian physics and Spinozist rationalism
was mounting. In other words, Newton became so successful not because he was right, but because
he was useful. In the Dutch context, his work was increasingly considered as much more than a
physical the- ory, but as the incontestable basis of a Christian philosophy of nature. Inspired by Cotes'
foreword to the Principia and the remarks in the Scholium, the book was no longer seen as a rather
abstruse hypotheti- cal description of the world system, but as a major achievement in natural
philosophy. Dutch culture at this time showed a preoccupa- tion with mathematicians and the
problem of certainty, as well as with atheism, and 'Newtonianism' was now presented as the answer
to all these problems.

The pirated Amsterdam edition of the 1713 Cambridge version of the Principia

As is well known, the real triumph of Newton on the Continent start- ed with the second edition of
the Principia.57 The Cambridge edition
was published in May 1713, and according to a list personally made by Isaac Newton, probably some
seventy copies were distributed as pres- entation copies, among which were four for the university
libraries in Leiden, Utrecht, Franeker and Groningen.58

Bearing in mind that, among the group of scientific enthusiasts in Amsterdam, Newton was seen as
an anti-atheistic and trustworthy guide to a new handling and study of nature, we can now
understand better why within a few months after the second Cambridge edition of the Principia, a
pirated version was printed, with a new typeface and re-engraved plates, in the city. In the Newtonian
scholarship little attention is given to this Amsterdam edition, which appeared first in 1714, and was
reprinted in 1723 in a slightly expanded version (fig. 1),59 A closer look at these two pirated editions
reveals some intriguing facts, relevant to a better understanding of the reception of Newton in the
Republic.

The Amsterdam edition was announced in July/August 1713 in a new Dutch-issued journal in French,
the Journal littéraire de La Haye. The anonymous journalist wrote that this reprint was to be
published by a company of booksellers ('une compagnie des libraires') and would be based on the
second edition of the Principia which had just been

27
28

NEWTON AND THE NETHERLANDS

published in England (qui vient de paroître en Angleterre').60 Obvi- ously, the editors of the Journal
were very well informed about events both in England and in Amsterdam. It soon turned out that the
pirat- ed edition was issued as a joint venture of at least ten Amsterdam booksellers and printers,
using the device Vis unita major (The unit- ed force is greater). This company was founded in 1711 in
response to an agreement between 54 book publishers from Amsterdam, Leiden, The Hague,
Rotterdam and Utrecht, in an attempt to regulate the book trade. The pirating of foreign books was
also discussed in this com- pact, which in some cases would be an enterprise only to be tolerated if it
was a concerted action, with a shared profit."

In regard to the Principia the obvious question is: why would such a large group of booksellers expect
a profit from the illegal issue of a just-reprinted difficult book, the sales of whose first edition of 250-
400 copies had been notoriously poor? Why did they expect to profit from this investment? And who
took the initiative for this costly enterprise - with an estimated print run of 750 copies - and for what
reasons?62 As we will outline below, the 1714 Amsterdam reprint coincided with a Newtonian
offensive not only by Le Clerc, but also by Boerhaave, Nieuwentijt, 's Gravesande and the versatile
scholar Lambert ten Kate. As Meindert Evers has already remarked in a survey of Newton's recep-
tion in one of Le Clerc's journals, it seemed that this was a konzertierte Aktion: a coordinated action
to put Newton firmly on the map, as well as on the market. The truth of this claim remains a matter
of specula- tion, but it cannot be disputed that within three years of the launch of the second edition,
many Dutch professors and non-academics, both in Latin and in the vernacular, strongly spoke out in
favour of Newton and his method. So let us examine the Amsterdam reprint in greater detail. Who
might have been involved in it?

Let us start with the announcement in the Journal littéraire of July/ August 1713. This journal had
been started just a few months before by Thomas Johnson, a Scottish bookseller whose shop in The
Hague was a centre for British citizens residing in Holland. It was probably Johnson who organized a
steady correspondent for the Journal littérai- re in London, in the person of Pierre des Maizeaux (c.
1666-1745), a Huguenot and an acquaintance of Le Clerc.64 In 1720 Des Maizeaux would also edit
the Amsterdam edition of the famous Leibniz-Clarke correspondence on the priority dispute with
Newton in regard to the invention of differential calculus.65 Since 1708 Johnson had maintained
close contacts with the Amsterdam publisher Jean-Louis de Lorme (one of Le Clerc's main publishers),
who (until his departure to France in 1711) provided him - as the only bookseller in The Hague - with
a copy of all the 'livres étrangers' published in Amsterdam.66 After 1711 De Lorme's role as Le Clerc's
publisher and probably also as Johnson's provider of foreign books was taken over by the brothers
Rudolf and Gerard Wetstein." This publishing company participated in the Vis unita major book
company that would publish the Principia. So it is evident that information, both from the English
edition of the Prin- cipia and from the Amsterdam initiative, came together in The Hague. Then there
was the editorial board of the Journal littéraire. At its very start in 1713 the journal was run by two
Dutch Huguenots, Albert Henri de Sallengre (1694-1723) and Thémiseul de Saint Hyacinthe (1684-
1746), together with two genuine Dutchmen, Justus van Effen (1684-1734) and Willem Jacob 's
Gravesande. As Ad Maas describes in his contribution to this volume, in later years 's Gravesande
would become the most influential figure in spreading the fame of Newton and systematizing a
natural philosophy he called 'Newtonianism'. But in 1713 's Gravesande was still working as a lawyer
in The Hague, having finished his education at Leiden University in 1707, where he had matriculated
in the faculty of law three years before. However, 's Gravesande had been interested in mathematics,
physics, ethics and philosophy for a long time and during his student years he even wrote a work,
Essai de perspective, which was published in The Hague in 1711. There he became one of the
founders of the Journal littéraire (1713). Most likely, it was 's Gravesande who was the editor
responsible for the many articles devoted to physics and mathematics.68 Generally, the Journal took
a leading role in propagating books on natural theolo- gy, such as Derham's Physico-theology, with
the explicit aim of refuting atheism.69

We know for certain that 's Gravesande was acquainted with Ber- nard Nieuwentijt, who was directly
related to the Amsterdam mathe- maticians. Contacts between Nieuwentijt and 's Gravesande date
back to 1712, when the latter made a calculation on the ratio of the number of newborn boys and
girls, a piece which Nieuwentijt would include in his aforementioned book, Het regt gebruik.70 This
bestseller was pub- lished in 1715 by the widow of Johannes Wolters, together with her son from an
earlier marriage, Joannes Pauli. They too were participants in the Amsterdam Vis unita major
company that brought the Principia

29

THE MIRACLE OF OUR TIME

30

together with Willem Jacob's Gravesande, the main constructor of Dutch 'Newtonianism'.

into print. As a matter of fact, in Het regt gebruik some vignettes are exactly identical to those used in
the pirated edition of the Principia."

When we combine these facts with a statement made in 1722 in a letter by Nicolaas Struyck (1687-
1769), an Amsterdam mathematician with close connections to the Amsterdam Vis unita major
publishing consortium, the identities of the actors responsible for the Amsterdam Newton editions
becomes more clear.?72 To one of his correspondents Struyck remarked that he had found some
printing errors in his own 1714 Amsterdam copy of Newton's Principia, which faults he would report
to 'Professor 's Gravesande, who is here supervising a third edi- tion. Obviously this was not a
statement concerning the genuine third London edition, issued by Cotes in 1726, but rather the
second Amsterdam printing of the Principia. This edition with a new typeface was issued in 1723.
Moreover, this second Amsterdam printing would become the only version in which Newton's wish to
include four small mathematical tracts was fulfilled. Who else than a person with close
contacts to Newton could be aware of this wish of the great 'Master'?74 With this knowledge in
mind, it seems plausible that a collective effort of Le Clerc, 's Gravesande and, perhaps, Nieuwentijt,
was the driving force behind the Amsterdam printing of 1714. 's Gravesande probably played the
same role at the second extended print run of 1723.

Putting Sir Isaac on the shield: The construction of an anti- atheistic Dutch 'Newtonianism'

In early 1715 Jean Le Clerc contributed to the 'new' Newtonian offen- sive by including in his
Bibliothèque ancienne et moderne a French translation of large parts of a book by the British
'Newtonian' George Cheyne, entitled Philosophical Principles of Natural Religion (London 1705). In
this publication Le Clerc again pointed to 'the most sublime and very important truths' that Newton
had discovered.75 Based on Le Clerc's lengthy summary in the Bibliothèque, the aforementioned
Lam- bert ten Kate soon made a loose Dutch translation, to which he added extensive personal
remarks.76 Like his close friend Verwer, Ten Kate had a Mennonite background. As a well-to-do
citizen, he could spend most of his time as a virtuoso, studying history, the arts, linguistics, philosophy
and the natural sciences. Ten Kate certainly used Newton's thoughts on religion to promote scientific
interest among the Dutch. The long title of his adaptation of Cheyne, published in 1716, leaves little
doubt as to Ten Kate's interests: Den Schepper en Zyn bestier te kennen in Zyne schepselen (To Know
the Creator from His Creatures, According to the Light of Reason and Mathematics, [written] to Cul-
tivate a Respectful Religion; to Destroy the Basis of Atheism; and for an Orthodox Use of Philosophy)."
According to Ten Kate, all scientif- ic research should be subservient to a better understanding of
divine Revelation. In the introduction of his book, Ten Kate underlined the fact that Descartes'
mechanical philosophy led to Spinoza's system. However, both philosophers had neglected
experience and experi- ments, and had abused mathematics, but some distinguished men in England,
who disliked the uncertainties of hypotheses, have based themselves only on a Philosophia
Experimentalis, by means of mathe- matics'.78 The success of this approach was demonstrated by
'the most famous mathematician Newton' who had discovered the law of grav- itation, thereby
eliminating the dangers of philosophy and putting mathematics at the basis of religion: 'Sir Newton
gave such a mathe- matical account of Nature, that man cannot but see God's hand in the

31

THE MIRACLE OF OUR TIMET

 NEWTON AND THE NETHERLANDS appearances (as Professor Cotes justly states in
the second edition of Newton's work)'.79 Le Clerc was very pleased with Ten Kate's
work. It was the only book in Dutch ever to be reviewed in the Bibliothèque ancienne et
moderne. In their approval of Newton's method, Le Clerc and Ten Kate were followed by
Herman Boerhaave. The Leiden professor, without any doubt the most famous Dutch
scholar of his time, was the first aca- demic to speak publicly in Newton's favour.80 The
occasion on which Boerhaave delivered his Sermo academicus de comparando certo in
physicis was highly symbolic and without doubt deliberately chosen. It was on 8 February
1715, the 140th anniversary of Leiden Universi- ty, and the day Boerhaave resigned as
Rector Magnificus. Instead of addressing a medical subject, Boerhaave raised his
eloquent voice to make a bold statement that concerned the members of all faculties.
Since physics was essentially the study of God's creation, the meth- od followed was of
relevance to Christian society as a whole. In plain language, Boerhaave rejected the
speculations by Descartes and the dangerous pretensions by some ungodly
mathematicians, i.e. the Spi- nozists. Instead, he advocated the method of Newton, 'the
miracle of our time', 'he who deserves everywhere to be honoured as the lead- ing
figure', 'the Prince of Geometricians'. It was only through New- ton's method that
certainty was to be achieved: 'Everything that has been discovered in physics by
geometricians through deduction from observation stands with such unshaken truth that
not a single mortal has any doubt on these points - whereas fictions soon collapse and
show their true nature'.82 Although some orthodox Cartesians, such as the Franeker
professor of philosophy Ruardus Andala (1665-1727), protested vehemently, it was clear
that the intellectual climate was changing. As Rina Knoeff notes in her contribution to this
volume, Boerhaave himself, after his programmatic and highly political ora- tion, never
introduced Newton's ideas into his courses, nor paid much attention to the Englishman.
This only reinforces the impression that Boerhaave's outburst in favour of Newton was
part of a coordinated action. To be sure, only a few months later, Bernard Nieuwentijt
published his Het regt gebruik der wereldbeschouwingen, which was an explicit attack on
Spinoza. In this book Nieuwentijt pointed out how sound scientific principles demonstrate
the wisdom and power of the Crea- tor. Science was here mainly understood as
experimental physics and