Christian Foundations of the Idea of Laws of Nature
Above: God the Father on a throne, Westphalia, Germany, late 15th century. [See https://commons.wikimedia.org/wiki/File:Gottvater_thronend_Westfalen_15_Jh.jpg Only a part of the painting is reproduced above.]
Christian Foundations of the Idea of Laws of Nature 1
That science is possible at all is ultimately owing to the intelligibility of nature. Were it not for the fact that the natural world seems to operate according to a set of invariable principles, and that human minds have the capacity to discover or intuit those principles, there would be no science as we know it. In different periods of history, and across diverse cultures, the regularities of nature have been conceptualised in different ways, giving rise to different kinds of sciences. But in the seventeenth century a quite specific and unprecedented understanding of nature’s intelligibility arose in the West: the idea that the world was governed by laws of nature. As we will see, the novel idea that nature was governed by laws developed out of a specific set of theological assumptions. Laws of nature were understood as God’s imposition of an invariant mathematical order onto a world of inert matter, and all of the motions in the universe were thought to result directly from God’s willing them. ‘Law’, in this instance, was thus no mere metaphor, but was grounded in the supposition of a divine law-giver. This idea became a central premise of modern science
In order to understand the significance of the seventeenth-century shift towards explanation in terms of laws of nature, along with the theological justifications of this new conception, we need to consider the dominant understanding of the regularities of nature that preceded it. From about the thirteenth century onwards the standard philosophy of nature taught in the medieval universities was Aristotelian in character. The Greek philosopher had proposed that the regularities of nature are not imposed from ‘outside’, as it were, but resulted from the internal properties of things — their inherent qualities and virtues. This view was subsequently Christianized by thinkers such as Thomas Aquinas, who maintained that these qualities and virtues had been embedded within natural objects by God. Accordingly, Aquinas spoke of ‘the order that God has implanted in nature.’ 2
Unlike modern laws of nature, this internal order was not manifested in immutable rules, since these implanted powers could, on occasion, miscarry, giving rise to exceptions to the usual course of events. The example Aquinas offers is that of an individual born with six fingers on each hand.3 Again, Aquinas was following Aristotle. Both thinkers understood the course of nature as ‘that which is wont to occur in things for the most part, but it is not everywhere in keeping with what always occurs.’ 4 There was no sense, then, that apparent exceptions to the common course of nature needed to be incorporated within an overarching framework of lawful regularities. More generally, Aristotelian science concerned itself with what were imagined to be the unchanging essences of individual things.5
Another point of difference between medieval and modern science concerned the role played by mathematics. The ancient and medieval sciences were organized very differently from present-day science. (In fact, our English word ‘science’ only took on its modern meaning during the nineteenth century.) Aristotle had carefully distinguished between natural philosophy, the science concerned with genuine causal explanations, and mathematics, which was concerned with human abstractions.6 The study of the motions of celestial bodies, for example, could be treated under two distinct rubrics: natural philosophy, which dealt with the causes of the motions of the stars and planets; and mathematical astronomy, which provided mathematical models for predicting the positions of the objects in the heavens. Simplifying things somewhat, natural philosophy was a realist enterprise, while astronomy was instrumentalist. A mathematical model might accordingly be regarded as ‘saving the appearances’ — that is, providing an account that yielded good predictions — without being taken as a true representation of the relevant motions.7 This was the point that Osiander attempted to make in his controversial preface to Copernicus’s De revolutionibus (1543). The hypothesis of a sun-centered system, Osiander explained, was to be understood within the disciplinary framework of mathematical astronomy, not natural philosophy. Although physically impossible (as natural philosophy) the heliocentric model nevertheless yielded good predications and hence had merit as mathematical astronomy.8 This principle was also a key issue in the Galileo affair, with Pope Urban VIII proposing that the Copernican hypothesis be understood as one of a number of possible instrumentalist models, while Galileo insisted on a realist interpretation.
During the late Middle Ages, and into the Renaissance and Reformation, challenges were issued to each of these elements of the Aristotelian worldview. Speculations about the absolute power of God, along with an emphasis on God’s unconstrained freedom to will any state of affairs, promoted a questioning of the relative autonomy of the Aristotelian natural order. The revival of mathematical mechanics, along with the emergence of a new Christian Platonism that stressed the reality of mathematical relations, opened up new possibilities for the application of mathematics to natural philosophical problems. Other schools of Greek thought were also revived, further eroding the intellectual monopoly exercised by Aristotelianism. Most notable amongst them, for our purposes, was the atomism of Democritus and Epicurus. Atomistic or ‘corpuscular’ theories of matter implied that matter was essentially inert, in contrast to Aristotelian assumptions about the inherent purposefulness and causal efficacy of natural objects. Subsequently, the Protestant Reformers were to reinforce these developments by critiquing the dominance of Aristotle’s ‘pagan’ philosophy in scholastic thinking. The Reformers also stressed, in an unprecedented way, the sovereignty of God and the primacy of the divine will.
This changing intellectual environment prompted a new set of questions about God’s relation to nature. If God was the creator of the world, it seemed logical that he had issued physical laws that were in some sense analogous to the moral laws prescribed in Scripture. And if mathematics were a product of the divine mind, rather than just a human abstraction, perhaps geometrical and mathematical relations were a real feature of the structure of the world. Finally, if the world were a divine artefact, then Aristotle’s distinction between natural and artificial was questionable, and it would make sense to apply the knowledge gained from the operations of humanly constructed machines (i.e. mechanics) to the operations of nature itself. All of this set the scene for the emergence of the modern notion of laws of nature.
The French natural philosopher René Descartes was the first to formalize the idea of laws of nature and provide examples.9 In his Principles of Philosophy (1644), he speaks of the creation of the world, telling us that ‘God imparted various motions to the parts of matter when he first created them, and he now preserves all this matter in the same way, and by the same process by which he originally created it.’ This was a quite radical claim, suggesting that all motion in the world results from God’s constant and direct action. Motion, in a sense, is God’s ongoing re-creation of inert particles in different points in space. This does not give rise to a chaotic or arbitrary world, however, for as Descartes explains, God’s immutability guarantees the constancy of what he wills. God’s immutability, in other words, underwrites the constancy of the laws of nature. Descartes went on to identify three such laws of motion.10
Descartes’ world is radically different from that of Christian Aristotelianism. In the latter, change occurs on account of the active powers of natural things (although God both conserves things in existence and lends his active ‘concurrence’ to the operation of their secondary causal powers).11 In the Cartesian world, God does all the work, albeit in keeping with a regular pattern that he himself has willed. In fact, for Descartes, all necessary relations — not just the laws of nature, but also the laws of mathematics and logic — ultimately depend on the God’s will. Mathematical truths, he says, ‘were established by God and totally depend on him just like all the other creatures.’ 12
If Descartes provided a theological justification for the existence of laws of nature, Johannes Kepler provided reasons for their mathematical character. He was acutely conscious that in doing so he was rejecting Aristotle’s attempt to keep mathematics and natural philosophy apart, but provided a theological justification for doing so:
God the Creator, since he is a mind, and does what he wants, is not prohibited, in attributing powers and appointing circles, from having regard to things which are either immaterial or based on imagination. And since he wills nothing except with absolute reason, and nothing exists except by his will, then let my adversaries say what other reasons God had for attributing powers, etc. since there was nothing except for qualities.13
Kepler would argue elsewhere that Aristotle’s inability to conceptualize a world founded on mathematical principles was owing to the fact that he had no doctrine of creation. A mathematical natural philosophy that was unacceptable to Aristotle, Kepler wrote, is ‘acceptable to me and to all Christians, since our faith holds that the World, which had no previous existence, was created by God in weight, measure, and number, that is in accordance with ideas coeternal with Him.’ 14 All of this makes possible the conviction that mathematical laws are not just human constructions and devices for calculation, but rather describe the real relations that obtain between physical objects in the universe.
Newton’s masterwork, the Principia mathematica (1687) represents the culmination of the trends evident in Kepler and Descartes. The title of the work — ‘Mathematical Principles of Natural Philosophy’ — bears witness to Newton’s insistence on combining mathematics and natural philosophy, while the work itself contains his three laws of motion along with an articulation of his celebrated universal law of gravity.15 In his preface to the book, Newton explains that whereas the ancients (i.e. Aristotle) had pursued the investigation of nature by attempting to identify ‘inherent forms and qualities’ in things, the moderns ‘have undertaken to reduce the phenomena of nature to mathematical laws’.16 Elsewhere he wrote that phenomena such as gravity are not qualities inhering ‘in the specifick forms of Things’ but rather result from ‘general Laws of Nature.’ 17 The preface to the second edition of the Principia makes the theological connection explicit:
… this World — so beautifully diversified in all its forms and motions — could not have arisen except from the perfectly free will of God, who provides and governs all things. From this source, then, have all the laws that are called laws of nature come, in which many traces of the highest wisdom and counsel certainly appear, but no traces of necessity.18
Here, again, the emphasis is on the freedom of the divine will to impose whatever regularities upon nature that it chooses, along with the proposal that the wisdom of God is evident in the fitness of the laws.
Later Newtonian thinkers reinforced these new conceptions. In the very first of the Boyle Lectures, delivered in 1692, the polymath Richard Bentley declared that ‘all the powers of mechanism are dependent on the Deity’. This was ultimately because ‘gravity, the great basis of all mechanism, is not itself mechanical, but the immediate fiat and finger of God, and the execution of divine law.’ 19 Others within Newton’s circle also adopted the view that all that happens in nature does so as the direct consequence of God’s willing it. Isaac Barrow, the first Lucasian Professor of Mathematics at Cambridge and Newton’s immediate predecessor in that famous chair, baldly stated that ‘the efficient Cause of all Things is God.20 God’s oversight is unmediated, moreover, for he ‘uses no other means, instruments or applications in these productions, than his bare word or command.’ 21 Samuel Clarke, the most philosophically able theologian of his generation and best known as Newton’s spokesman in the famous controversy with Leibniz, also contended that laws of nature were nothing other than God’s volitions: ‘the Course of Nature, cannot possibly be any thing else, but the Arbitrary Will and pleasure of God exerting itself and acting upon Matter continually.’ 22
In sum, while Descartes had introduced the idea of divinely originated laws of nature, and Kepler brought mathematics on board, it was the Newtonian system that made mathematical laws the bedrock of modern physics. Like Descartes and Kepler, Newton and his followers were unambiguous about the theological foundations of those laws.
It is curious, given this history, that appeals to laws of nature are now often thought to render theistic interpretations of the natural world redundant. This ‘naturalistic’ tendency first arose in the nineteenth century when the theological origins of the concept of laws of nature was sufficiently historically distant to be quietly forgotten. But as the history outlined above suggests, resting content with laws of nature as a sufficient explanation is really a failure to pursue the enquiry to its proper terminus. As the astute Austrian-British philosopher Ludwig Wittgenstein observed: ‘At the basis of the whole modern view of the world lies the illusion that the so-called laws of nature are the explanations of natural phenomena. So people stop short at natural laws as at something unassailable, as did the ancients at God and Fate.’ 23 By way of contrast, for the seventeenth-century originators of the concept, ‘laws of nature’ were unthinkable without a divine law-giver. It would not seem unreasonable to argue that present-day appeals to laws of nature involve the same tacit commitment.
[Peter Harrison has been since 2015 the Director of the Institute for Advanced Studies in the Humanities at the University of Queensland. Before that he was Andreas Idreos Professor of Science and Religion at the University of Oxford and Director of the Ian Ramsey Centre. He delivered the 2011 Gifford Lectures at the University of Edinburgh (published as The Territories of Science and Religion by University of Chicago Press), and the 2019 Bampton Lecture at the University of Oxford. He is the recipient of many other honors and awards for his scholarship and writing on the historical relation of science and Christian belief. He is the author, coauthor, or editor of many books. He is editor of The Cambridge Companion to Science and Religion (Cambridge University Press, 2010).]
1.. This article is based on material from two book chapters: Peter Harrison, ‘The Development of the Concept of Laws of Nature’, in Fraser Watts (ed.), Creation: Law and Probability (Ashgate, 2008), pp. 13-36, and Peter Harrison, ‘Laws of Nature in Seventeenth-Century England: From Cambridge Platonism to Newtonianism’, in Eric Watkins (ed.), The Divine Order, the Human Order, and the Order of Nature: Historical Perspectives (New York: Oxford University Press, 2013), pp. 127-48.
2.. St. Thomas Aquinas, Summa contra gentiles III, 100.
3.. Aquinas, Summa contra Gentiles III, 99.
4.. Aquinas, Summa contra gentiles III, 99.
5.. Aristotle, Metaphysics 1026b- 1027a, 1064b-1065a. For Medieval and Renaissance versions of this view see Aquinas, Commentary on the Metaphysics of Aristotle 11.8.2276, tr. John P. Rowan, 2 vols., (Chicago: Henry Regnery, 1961), Vol. 2, p. 814; Matteo Palmieri, Civil Life II, in Renaissance Philosophical Texts, ed. Jill Kraye, 2 vols., (Cambridge: Cambridge University Press, 1997) vol. 2, pp. 149-72 (esp. p. 153).
6.. Aristotle, Posterior Analytics 75b. On earlier understandings of science see Harrison, The Territories of Science and Religion, (Chicago: University of Chicago Press, 2015), pp. 11-16.
7.. As Aquinas put it: ‘Yet is not necessary that the various [mathematical] suppositions which they [astronomers] hit upon were true—for although these suppositions save the appearances, we are nevertheless not obliged to say that these suppositions are true, because perhaps there is some other way men have not yet grasped by which the things which appear as to the stars are saved.’ Exposition of Aristotle’s Treatise on the Heavens II.17.451, tr. R. Larcher and P. Conway, 2 vols., (Columbus: College of St Mary of the Springs, 1963-4), vol. 2, p. 74.
8.. ‘For it is not necessary that these hypotheses should be true, or even probable; but it is enough if they provide a calculus which fits the observations’. Nicolaus Copernicus, On the Revolutions of the Heavenly Spheres, tr. Charles Glenn Wallis (Amherst: Prometheus Books, 1995), p. 3.
9.. There were, admittedly, some medieval precedents for this terminology. A concept of ‘natural laws’ operated in the sphere of morality. Natural laws in this sense consisted in moral injunctions such as ‘Thou shalt not kill’. These were universal, and were related to divine law and divine commandments, but were natural in the sense that they were thought to be accessible to all rational individuals. It also worth noting that Jane Ruby and A.C. Crombie have pointed out that Roger Bacon (c. 1210—c.1292) spoke of ‘laws’ [lex, leges] of reflection and refraction, and of these collectively as ‘laws of nature.’ See A.C. Crombie, ‘The Significance of Medieval Discussions of Scientific Method for the Scientific Revolution’, Critical Problems in the History of Science (Madison: University of Wisconsin Press, 1959), p. 89; Ruby, ‘The Origins of Scientific Law’, Journal of the History of Ideas, 47 (1986): 341-59 (pp. 343f.). There were also interesting precedents for the Cartesian combination of occasionalism and atomic matter theory among ninth-century Islamic thinkers.
10.. Descartes, Principles of Philosophy, §§ 61, 63, 65, in The Philosophical Writings of Descartes, 3 vols., ed. John Cottingham, et al., (Cambridge: Cambridge University Press, 1985-91), vol. 1, pp. 240-2. For an account of Descartes’s role in developing the notion of laws of nature see John Henry, ‘Metaphysics and the Origins of Modern Science: Descartes and the Importance of Laws of Nature’, Early Science and Medicine, 9 (2004), 73-114.
11.. On conservation and concurrence see Alfred J. Freddoso, ‘God’s General Concurrence with Secondary Causes: Why Conservation is not Enough’, Philosophical Perspectives 5 (1991): 553-585.
12.. Descartes to Mersenne, 15 April 1630, Philosophical Writings, vol. 3, p. 23.
13.. Johannes Kepler, Mysterium Cosmographicum, tr. A.M. Duncan (Norwalk, CT.: Abarus, 1999), p. 123.
14.. Kepler, The Harmony of the World, tr. and intro. by E.J. Aiton, A.M. Duncan, J.V. Field (Philadelphia: American Philosophical Society, 1997), pp. 115, 146. The reference to ‘weight, measure, and number’ comes from the Book of Wisdom 11:12
15.. Isaac Newton, The Principia: Mathematical Principles of Natural Philosophy, tr. I. Bernard Cohen and Anne Whitman (Berkeley: University of California Press, 1999), pp. 416f.
16.. Newton, Principia, p. 381 (my emphasis).
17.. Newton, Opticks (New York, 1979), p. 401.
18.. Newton, Principia, p. 397. The preface to the 2nd edn. was written by Newton’s close collaborator Roger Cotes.
19.. Richard Bentley, Boyle Lectures, Sermon IV, in The Works of Richard Bentley, D.D., 6th edn., ed. Alexander Dyce (3 vols., London, 1836), vol. 3, pp. 74-5.
20.. Barrow, The Usefulness of mathematical learning explained and demonstrated, tr. John Kirby (London, 1734), Lecture VII, p. 109.
21.. Barrow, ‘Maker of heaven and earth’, (Sermon XII), in Theological works, (3 vols. London, 1885), vol. 2, p. 303. Cf. Isaac Newton, Unpublished scientific papers of Isaac Newton, ed. and tr. A. Rupert Hall and Marie Boas Hall (Cambridge: Cambridge University Press, 1962), p. 139; William Whiston, A New Theory of the Earth (London, 1696), pp. 6, 211.
22.. Samuel Clarke, ‘The Evidences of natural and revealed religion’, The Works of Samuel Clarke, D.D., 2 vols., (London, 1738), vol. 2, p. 698.
23.. Ludwig Wittgenstein, Tractatus Logico-Philosophicus, 6.371-372.