Science and British philosophy: Boyle and Newton

Science and British philosophy: Boyle and Newton G.A.J.Rogers INTRODUCTION Achievements in the natural sciences in the period from Nicholas Copernicus (1473– 1543) to the death of Isaac Newton (1642–1727) changed our whole understanding of the nature of the universe and of the ways in which we may acquire knowledge of it. These innovations had unprecedented implications for philosophy, and in Britain John Locke, George Berkeley and David Hume, were only the most famous of those philosophers whose work in large part reflected the scientific developments and the issues that they generated. Copernicus’s vision of a moving earth and a heliocentric universe found strong support in the observations of Galileo with the telescope in 1609, but the full intelligibility of the heliocentric view awaited a comprehensive physics to replace that of Aristotle. This new physics gradually took shape during the seventeenth century with Galileo and René Descartes prominent in its formulation. The zenith of this development was the publication in 1687 of Newton’s Mathematical Principles of Natural Philosophy, the Printipia, which provided a comprehensive mechanics that gave physical sense to the idea of a moving earth and provided a deep understanding of central physical concepts. It also generated an accuracy in scientific calculation and prediction scarcely previously conceived. The birth of the new cosmology and the new physics was accompanied by a revival of ancient atomist theories of matter. Like the new cosmology and physics, the new atomism came to the fore at the expense of Aristotle’s plenist theories of matter and space. The new atomism, suitably modified to minimize conflict with standard Christian theology, was most ably advocated in mid-century by Pierre Gassendi as part of a concerted attack on traditional Aristotelian or Scholastic philosophy. Other thinkers, before and after Gassendi, took up the campaign for atomism or some form of corpuscular theory of matter. Amongst these were Galileo, Thomas Hobbes and Descartes, indicative of a fruitful marriage between the new mechanics and corpuscularianism that remained at the heart of scientific achievement for the next two hundred years. In England the great advocate of the new atomism was the leading natural philosopher of the group who came to establish the Royal Society in 1660, Robert Boyle (1627–91). Boyle argued the case for ‘the new corpuscular philosophy’ in a series of works which were to have a great influence not only within matter theory but also, through the philosophy of John Locke, on epistemology. An important strength of Gassendi’s advocacy of atomism was that his version, whilst closely tied to that of Epicurus, was, nevertheless, argued from within a Christian theology. He was thus able to defuse the atomistic philosophy of what was standardly seen as its major liability, its association with atheism and an unacceptable hedonism. In England something similar was achieved by the Cambridge Platonists, especially Ralph Cudworth and Henry More. The former’s True Intellectual System of the Universe (1678), which argued a Platonic-Christian atomism, and the latter in many of his writings, provided a basis from within Anglican theology for the acceptability of atomic theories. With a powerful group of like-minded enquirers into nature they helped to foster an atmosphere in which atomist theories of matter became acceptable. Concurrently with these philosophical works Boyle was not only producing argument but, importantly, presenting experiments in favour of the corpuscular theory. His findings were to be published through the 1660s and 1670s and became influential sources for the two most prominent thinkers of the end of the century, John Locke (1632–1704) and Isaac Newton. Locke was not only a student of Boyle’s writings, he was also a junior partner in Boyle’s own scientific researches, conducted when they were both in Oxford in the 1660s. From an early point in his intellectual development Locke came to share Boyle’s commitment to the corpuscular philosophy. Similarly, we can, through his early notebooks, trace Newton’s close study of Walter Charleton’s version of Gassendi’s philosophy and the works of Boyle, and his early allegiance to a corpuscular account of matter. The corpuscular theory raised fundamental questions about matter’s basic properties which remain at the forefront of debate in the late twentieth century. It also raised in an acute form questions about how we can come to know what those properties are, or even if we have any reason to believe in an independent physical world at all. It was the implications of these accounts of matter that were to feature prominently in philosophy throughout the Enlightenment. The natural philosophers had themselves often been conscious of these wider implications. Boyle, for example, was well aware that the generally empirically-based method for acquiring knowledge that he strongly favoured was open to various challenges from the sceptic. The most famous response to this scepticism in the seventeenth century was that of Descartes (1596–1650). But Boyle, whilst well aware of Descartes’s achievement, was not himself attracted to the Cartesian solutions. Instead he chose to side-step the philosophical debate and pursue his researches in natural philosophy. Nevertheless, his account of matter and its properties both contained within it answers to philosophical questions and raised others that were to remain prominent and contentious issues. Newton’s Principia is famous for giving us the laws of motion and the theory of gravitation which provided a unified account of the physics of the heavens and the earth. But Newton also saw his science as exemplifying a method which he believed to be the most fruitful for enquiries into the physical world. Newton was himself influenced by the approach to nature that had emerged in England in the decades surrounding the English Civil War and which was much coloured by the programme for the investigation of nature that Bacon had advocated in the early part of the century. Newton added to that hard-headed empirical approach a mastery of mathematics which few have equalled. The combination was to produce the most powerful theory about the natural world than had ever been produced. Newton was himself aware of the debates about method that had dominated much seventeenth-century philosophy and he came down publicly very much in favour of an empirical methodology, even though he knew that it could never deliver that absolute certainty that could vanquish the committed sceptic. His final position emerged clearly in his later writings, especially in the second edition of the Principia (1713) and the later editions of the Opticks. In them he made his opposition to hypotheses, understood as empirically unsupported conjectures, very plain, and encouraged a commitment to the central place of careful observation, combined with minimal theory, a cornerstone of British physical science. Whether he was always quite consistent with his own principles is another, very interesting, question. One issue that was to raise a great deal of debate was the exact status of Newton’s claims for absolute space and time. Newton’s account was to be challenged by the great German philosopher and mathematician Leibniz, in a fascinating exchange with Newton’s spokesman, Samuel Clarke. Leibniz also challenged the acceptability of a central concept in Newton’s system, that of gravitation. It was, Leibniz urged, an occult quality, as unacceptable as the occult qualities of the scholastics that Boyle and Newton were so eager to reject. It was a criticism that found echoes in the philosophy of George Berkeley, also writing in the early eighteenth century. The issues raised remain to this day subject to fruitful dispute in both science and philosophy. THE NATURE OF MATTER At the beginning of the seventeenth century the accounts of matter and its properties taught in the universities throughout Europe remained versions of Aristotle and his scholastic commentators. Central to these were a belief in the four elements of earth, water, air and fire, and the rejection both of the possibility of a vacuum (‘Nature abhors a vacuum’) and of any kind of atomic theory. The properties or qualities of bodies, of which there were supposed to be four primary ones, heat, cold, dryness and wet, were linked with the four elements. Thus water was a combination of prime matter plus the qualities of cold and wet. Water itself was regarded as a secondary matter. The qualities that objects may have are either the primary qualities or secondary qualities, and the latter are a function of the combination of the primary matter and the primary qualities. Examples of such secondary qualities would be lightness and heaviness, softness and hardness. It is worth underlining that the terminology of primary and secondary qualities, which was to feature so centrally in Boyle and Locke was not invented by them, but was taken over from their rejected predecessors. But the list of such qualities and the explanations offered for them were to be radically changed. Another distinction drawn in the scholastic theory which was to be attacked by the corpuscularians was that between manifest and occult qualities. Whilst the scholastic primary and secondary qualities were all regarded as manifest, there were others, such as attraction, that were obscure or occult. Boyle was to see one of the great merits of the corpuscular account that it did away with these occult qualities of matter, explaining them as a function of more overt properties. Dissatisfaction with the scholastic theory emerged outside the universities and in particular in iatrochemical theory. Thus Paracelsus in Switzerland added to the traditional four elements three ‘principles’, mercury, sulphur and salt, in his chemical medicine. His alternative account attracted a wide following throughout Europe in the late sixteenth and early seventeenth centuries and had a significant impact onthe development of medical and chemical theory that is only now being fully appreciated. At about the same time interest in classical atomism was revived with the publication of Lucretius’ cosmological poem De Rerum Natura, and which itself led to a wider interest and enthusiasm for the philosophy, or such as had survived, of the Greek atomist Epicurus. Epicurus had not only provided an alternative account of the properties of matter, he also offered a model of change which was radically different from that of Aristotle. For Aristotle changes in the properties of a given object were to be accounted for by the object itself acquiring or losing qualities, hotness, wetness, and the like. For the atomist, however, change in the properties of an object was generally to be accounted for by change in the arrangements of its parts, the atoms of various shapes, and the great source of such change was motion of those parts.1 This new conception of matter and its properties received early expression in Galileo’s Il Saggiatore (1623). In a now famous passage he claimed that whenever he conceived of a material substance he had to think of it as having certain properties, of being bounded with a distinct shape and size and in some specific place, as being in motion or at rest, as touching or not touching other objects and as being one in number or few or many. These properties, he said, he could not separate from an object by any stretch of his imagination. It was, however, different with other properties such as taste, colour, sound and smell. These are not properties that one is compelled to regard an object as having and without our senses we would not have thought of them. So Galileo concluded that the latter qualities were not out there in the world but resided only in our consciousness and without living creatures they would not exist.2 Galileo’s claims are often taken to be the first modern espousal of the primarysecondary quality distinction that was to be made famous by John Locke. For Galileo it meshed with his atomism and his commitment to the centrality of mathematics to a proper understanding of the world. The book of nature, he said, was written in the language of geometry, and it was for him important that the primary qualities of objects were amenable to quantified analysis. Whether or not we see Galileo as the modern reviver of the distinction between primary and secondary qualities, the distinction itself must be seen as going together with the revival of Epicurean atomism or its near equivalent that was soon under way. This found particular expression in the writings of Pierre Gassendi, and the corpuscular philosophy of Descartes, where the primary-secondary quality distinction was most fully proposed in the latter’s account of perception in the Dioptrics. Gassendi found an English spokesman in Walter Char leton, whose Physiologia Epicuro-Gassendo-Charletoniana (London, 1654) became a widely read statement in English of the new atomism. Atomic theories of matter had begun to surface in England before the end of the sixteenth century, and in the works of Thomas Hariot, Walter Warner and Thomas Hobbes the theory received strong supporting argument. That argument, and more especially experimental evidence, for the corpuscular hypothesis was to reach an even greater level of sophistication in the writings of Robert Boyle. As a young man Boyle had travelled in Italy and was staying in Florence in January 1642, when Galileo died. Boyle was able to read Italian and he tells us that he studied Galileo’s books,3 but whether this included Il Saggiatore we do not know. It is, however, remarkable how close to that of the great Italian Boyle’s account of matter’s properties was later to be. The most comprehensive treatment of Boyle’s theory of matter was The Origin of Forms and Qualities, According to the Corpuscular Philosophy (1666, though much of it written many years earlier). In it Boyle expounds his reasons for rejecting the peripatetic explanation of matter’s properties and for substituting it with the much richer corpuscular theory. Boyle emphasizes his lack of dogma, and says that he is not concerned to argue finer points of metaphysics. Nor does he wish to confine himself to one particular version of corpuscularian theory such as that there are indivisible particles called atoms, or the physical theory of Descartes, which identified matter with extension and claimed a vaccum to be impossible.4 And neither does he intend to mix his exposition with matters of religion. Rather, he wishes his experiments and observations to be seen as leading naturally to the conclusions he draws. Before turning to the experimental evidence, however, Boyle explains what his theory is, the ‘hypothesis’ that will be confirmed or disproved by the ‘historical truths’ or experiments that are to follow. It begins from the acceptance of a ‘universal matter common to all bodies…a substance extended, divisible, and impenetrable’.5 Second, the cause of the variety of matter is the motion of its parts, introduced, no doubt, Boyle is happy to allow, by God, for there is nothing necessary about matter having any kind or degree of motion. With these ‘two grand and most catholic principles of bodies, matter and motion’ granted, Boyle is able to turn to matter and its properties or qualities. The matter of all natural bodies is, he says, the same, ‘namely a substance extended and impenetrable’. Differentiation between bodies depends on differences in their ‘accidents’ or qualities. Motion, which is not part of the essence of matter, is the most important ‘mood or affection’ of matter, and it is this motion and the resultant collisions which divides matter into its various fragments, themselves often too minute to be perceivable. Each one of these minute parts (as well as all larger bodies) must have its own determinate size and shape and be either in motion or at rest. And out of the conglomeration of the different minute parts arises the texture of the gross perceivable object of experience. These collections of particles—what we identify as particular material objects—come to our attention because they cause changes in us by ways which Boyle acknowledges remains problematic. But their affect is to produce in us the perceptions of such qualities as heat, colour, sound and odour. It is commonly imagined, says Boyle, that our perceptions “proceed from certain distinct and peculiar qualities in the external object which have some resemblance to the ideas their action upon the senses excites in the mind.’6 But this is not so, for all that there is in the body without us are the primary properties already listed. So Boyle is committed to saying that our ideas of such properties as colour and sound, although arising from real qualities of the perceived object, do not resemble their causes at all. They are, he says, ‘but the effects of the oftmentioned catholic affections of matter, and deducible from the size, shape, motion (or rest), order and the resulting texture, of the insensible parts of bodies’.7 Boyle anticipates what he perceives might be a serious difficulty for the corpuscular account of matter’s properties. It is that the explication of colours, sounds and such like by reference to our senses is incompatible with something else that we take to be true, namely that the colour, say, of an object is an objective property of the body, and not dependent on our senses: ‘snow (for instance) would be white, and a glowing coal would be hot, though there were no man or other animal in the world’.8 Boyle’s answer to this problem is to offer a dispositional account of the secondary qualities. There really is a difference between snow and coal, even in the dark, namely the dispositional property that if light were to shine on both one would cause the familiar experience of white in an observer and the other that of black, just as it is true, or not, that a particular musical instrument is in tune, whether or not it is actually being played. So far Boyle’s case for rejecting the scholastic account of properties in favour of his corpuscular theory is theoretical. But about half the Origins of Forms and Qualities consists of observations and experiments which Boyle argues can only be explained satisfactorily on the corpuscular hypothesis. Thus, drawing on his mastery of metallurgy and other chemically-based enquiries, he argues that what we now would see as examples of chemical change cannot be explained on the peripatetics’ principles, whereas they are entirely intelligible on the corpuscular account. In the 1650s Oxford was the scientific centre of England and even of Europe, and Boyle settled there in 1654. By this time he was already a skilled and knowledgeable chemist and wealthy enough to set up a laboratory in his house. He also initiated chemistry classes, and unsurprisingly came to occupy a dominant place in the scientific community. One of the people soon to be working most closely with him was the young John Locke, a professional contact that was to continue when they both moved to London in the late 1660s. It should not therefore come as any surprise to find that Locke was to draw on Boyle’s scientific ideas in writing his major work on epistemology, the Essay Concerning Human Understanding of 1690. A problem which arises from Boyle’s account of qualities and our perception of them might be expressed like this. If objects in the world cause us to have our experiences of them, and if those objects are only known to us through the effects that they produce on us or in us, and those effects, our experiences of the secondary qualities such as colour and sound, for example, do not exist in the objects in the same way as we experience them, then is there not also a problem about knowing that our experiences of the primary qualities do resemble properties as they actually are in the objects? That, and related questions, have continued to concern philosophers since the seventeenth century, and although Boyle seems never to have considered the issue, we can be sure that it was one that does emerge from his and similar accounts and it was to be one that was to play a large role in philosophical discussion from this point on. It is worth underlining here that the problem arises out of the new corpuscular philosophy and its associated account of perception, and it is to feature strongly in the argument of Locke, Berkeley and Hume in Britain and, on the continent, it is central to the philosophy of Kant. THE MECHANICAL PHILOSOPHY Boyle’s account of the properties of matter was part of his wider commitment to the mechanical philosophy. Various versions of this were already well known by the time that Boyle began to publish his own works. The two most powerful versions were Descartes’s Principles of Philosophy (1644) and Hobbes’s Leviathan (1651). But neither, for somewhat different reasons, was wholly convincing to British readers. The third great exponent of the mechanical philosophy in mid-century, Pierre Gassendi, was well known to the English exiles in Paris in the Civil War and Interregnum, and his philosophy reached a wider British audience with the publication in 1654 of Walter Charleton’s Physiologia Epicuro-Gassendo-Charltoniana. The full title of the work well explained its content for it continued Or a Fabrick of Science Natural, Upon the Hypothesis of Atoms, Founded by Epicurus, Repaired by Petrus Gassendus Augmented by Walter Charleton. Essentially it was a translation of Gassendi’s account of Epicurean physics, with supplements supplied by Charleton himself. According to Charleton the physical world could be understood as a mechanical system governed by the following ‘general Laws of Nature’: ‘(1) That every effect must have its cause; (2) That no cause can act but by motion; (3) That nothing can act upon a distant subject…but by contact mediate or immediate’.9 The last of these ruled out the possibility of ‘action at a distance’, with its language of sympathies and antipathies beloved of the natural magicians from whom Charleton and the atomists generally wished to distance themselves. Charleton’s work was undoubtedly influential, but it appeared at a time when another, altogether more powerful figure was in the ascendent, namely Boyle himself, and it was to be the account of the mechanical philosophy which he produced that was to become the most widely regarded, not least because Boyle was not only recognized as a leading natural philosopher in his own right, a position that Charleton never achieved, but also because his social standing and religious piety were never in question, matters of great importance to the acceptability of an account of nature which all too easily could be identified as subversive of state, church and morals. What precisely Boyle understood by the mechanical philosophy has already in part been noticed in his claim that everything in the physical world may be understood in terms of matter in motion, but a fuller understanding of the new mechanical philosophy requires first of all a backward glance at Aristotle’s explanation of change. Fundamental to Aristotle’s account of change was the principle that nature always acts for the sake of something. In other words, all natural change is goal directed. Such a teleological view of nature still has its place in some aspects of biological explanation. Thus we can ask of any particular organ of the body what its function is. And we can be told that, for example, the function of the heart is to pump the blood round the body. This characteristically biological explanation was generalized by Aristotle to the whole of the natural world. Thus he explained the falling of a stone towards the ground as manifesting the inclination of the stone to reach the centre of the universe, which was the ‘natural place’ towards which all objects made of earth matter-one of the four elements—were naturally inclined. Each element—the other three were water, air and fire—had its own natural place and objects would move according to their composition—objects made of liquid towards their natural place above the earth matter and below the air, and so on. For some time before Boyle this account of the elements had been found wanting by a variety of natural philosophers. Amongst thesewere the followers of the sixteenth-century Swiss known as Paracelsus, who generated an alternative chemical theory that achieved a wide following in the early seventeenth century. Paracelsus and his followers were primarily interested in producing a new chemical medicine which was linked to their understanding that human beings were a microcosm of the wider universal macrocosm. The great debate about the merits of the Paracelsian theory was a feature of seventeenthcentury chemistry that Boyle was party to and his own espousal of the mechanical philosophy was in conscious opposition to both the peripatetics and the Paracelsians, or, as he often calls them, the ‘chemists’. Boyle was happy to use the results obtained by the chemists if they were successful cures for ailments, but he was unpersuaded by their theory, at least for the most part. Instead, he proposed the mechanical philosophy as the best account of chemical change and other natural changes as well. He abandoned also the Aristotelian commitment to final causes in nature and in one of his works, A Free Enquiry into the Vulgarly Received Notion of Nature, which remains a classic analysis of the concept, he comes close to abandoning completely any appeal to the concept of nature to explain anything. Rather, he holds that it seems manifest enough that whatever is done in the world, at least wherein the rational soul intervenes not, is really affected by corporeal causes and agents, acting in a world so framed as ours is, according to the laws of motion settled by the omniscient Author of things.10 It was this notion of the laws of motion that was central to the mechanical philosophy’s account of change. Granted enough variety in the fundamental particles, variety of shapes and sizes, and a settled finite set of laws of motion, then it was possible, Boyle believed, to account purely on the basis of mechanical principles for the wide variety of events that can be observed. He included in this not only the gross movements of the planets and the other large objects but also what we now think of as chemical change and indeed also the way in which propagation of the species is achieved.11 The merits of the mechanical hypothesis were seen by Boyle to be many. Thus in contrast to the accounts of the peripatetics, the mechanical principles were very clear. Further, it was the simplest possible hypothesis, because there could not be fewer principles than those of matter and motion—there could not just be matter, for matter alone would be inactive. And, he held, neither matter nor motion can itself be resolved into anything simpler. But for Boyle the clinching argument in favour of the mechanical hypothesis is its power of explanation, or, as he calls it, its comprehensiveness. With the assumption of a limited number of basic corpuscles of various shapes, moving at variable speeds, we can account for the vast number of varying properties that we discover in the world in rather the same way that the limited number of letters of the alphabet can account for all the works of literature written in various languages. Further, the mechanical hypothesis is not incompatible with many of the claims of other theories, for example the chemical theory of van Helmont, and their accounts can largely be comprehended within it.12 Under Boyle’s influence especially, the mechanical philosophy became accepted by the virtuosi associated with the establishment of the Royal Society in Restoration England as the most plausible account of the natural world. It might seem that the publication of Newton’s Principia only added massive support to the mechanical hypothesis, for at first sight it seemed to provide an explanation of the motion of objects that was entirely in keeping with the mechanical model. But Newton himself rarely referred to the mechanical philosophy—the most famous occasion being in a letter to Boyle in 1679.13 But he was very keenly aware that the introduction of the law of universal gravitation, whilst correctly reflecting the observed facts of motion, was not itself explained. Although he held that ‘inanimate brute matter’ could not affect other matter without mutual contact, thus ruling out action at a distance as a possible power of material objects, he made no claims to know what the cause of gravity might be. ‘Gravity’, he said, ‘must be caused by an agent acting constantly according to certain laws, but whether this agent be material or immaterial I have left to the consideration of my readers.’14 There is some reason to suppose that Newton actually believed that the direct cause of gravitation was indeed immaterial, and that it was God himself, a view linked to his belief that the Deity was co-present and co-extensive with the infinite universe.15 There were, then, according to Newton, two kinds of things in the universe. There were particles of matter, which combined into gross material objects, and there were immaterial active agents. In his Opticks Newton characterized matter in this way: it seems probable to me that God in the beginning formed matter in solid, massy, hard, impenetrable, movable particles, of such sizes and figures, and with such other properties and in such proportion to space as most conduced to the end for which he formed them; and that these primitive particles being solids are incomparably harder than any porous bodies compounded of them.16 These particles are moved, Newton went on, not only by the normal laws of contact dynamics, which flow from their natural inertial motion, but also by ‘certain active principles’ such as that of gravity and the forces which generate the cohesion of gross objects. With this we may see that Newton held, later in his life at least, a position quite different from that of the mechanical philosophy if this is supposed to suggest some simple allegiance to Epicurean atomism. His position was a long way away from Hobbes’s materialist philosophy that the only things that exist are lumps of matter and the only cause of change is motion. Indeed Newton could not have accepted Boyle’s view that, God and minds aside, the only principles are those of matter and motion. Rather, for Newton the immaterial principles that the mechanical philosophy thought had been ejected from physics, and even from the whole of creation, were, in his more speculative and secret thoughts, given a central role in his account of things. Why they were not as prominent in Newton’s published works as they might have been is a matter that will be touched on later when we consider his attitude towards the possibility of achieving knowledge of the natural world. Space and time Newton’s commitment to absolute space and time is a famous part of his account of the world and one which was to lead to considerable controversy. He appears to have been led to his absolutist position by a variety of considerations which included his admiration for the absolute theory of the Cambridge-Platonist philosopher, Henry More, who, incidently, like Newton, came from Grantham. More had argued against Descartes’s relativist account of space that the existence of a Deity required the two absolutes of space and time in which God’s existence could be placed. Indeed More went further, for he believed that everything that exists, whether material or immaterial, must be extended (i.e. must be a space-occupier with dimensions). In this he was very conscious of his disagreement with Descartes, who had identified matter and extension, and who held that all mind-substances, including ourselves and God, were necessarily unextended entities. But God, as an infinite being, was for More an infinitely extended being—i.e. He was omnipresent both spatially and temporally. The extent and nature of More’s account of space can only be gestured here, but the relevant points for understanding Newton’s position are that More took space to be an absolute the properties of which can be described by geometry (though More was himself no great mathematician), and that it is directly linked with the nature of a Deity. More thus combined natural philosophy with theology in a commitment to absolute space and time. His account was, at the same time, an attack on the mechanical philosophy, and specifically on Robert Boyle, for More was committed to establishing the impossibility of a purely mechanical (i.e. materialist) philosophy explaining all the phenomena of nature.17 These features were to reappear in Newton, but now cemented to the incomparably more powerful mathematical physics of the Principia. Essentially, he argued that physics required absolute space and time, and the existence of absolute space and time requires the existence of an infinite God. Thus in the scholium to Definition 8 he distinguished between absolute and relative space and time. That there was such a thing as absolute space and time followed, he said, from the existence of absolute motion, and absolute motion was known to exist because any object accelerating as a result of a force acting on it must be in absolute motion, for a force is precisely that thing that causes an object to change its state of rest or uniform motion. Such a state is exhibited, for example, whenever an object in rotation attempts to recede from the centre of rotation. We can only understand this to be an object which is absolutely rotating, i.e. moving in relation to absolute space. In the General Scholium added to later editions of the Principia Newton explicitly linked his physics with his theology. God, Newton says, is the Lord of his creation and from his true dominion it follows that the true God is a living, intelligent, and powerful Being; and, from his other perfections, that he is supreme, or most perfect…his duration reaches from eternity to eternity; his presence from infinity to infinity…. He endures forever, and is everywhere present; and, by existing always and everywhere, he constitutes duration and space.18 So, in Newton’s view, it is the existence of absolute space and time that entails the existence of an infinite deity and it is the new physics, Newton’s new physics, that requires absolute space and time to explicate the central concept of force. Newton’s commitment to absolute space and time was one of the topics of a famous exchange between the English philosopher divine, Samuel Clarke and the German philosopher, Leibniz. Leibniz had several objections to the introduction of absolute space and time, some of which related to his understanding of what kind of universe God might create. But a central claim of his was that space and time were not real things which could exist separately from phenomena. They were essentially relational concepts and did not exist before a world was created, as Newton implied.19 A relativist position not too distant from that of Leibniz was also taken by George Berkeley, though for rather different reasons. The fullest expression of that position occurs in his work, De Motu (1721) in which Berkeley argues that the concepts of absolute space and time are empty since it is impossible to conceive of absolute motion. Motion can only be recognized or measured, he says, through observation, and since absolute space cannot affect the senses cit must necessarily be quite useless for the distinguishing of motions’.20 The debate about absolute space and time was to continue through the eighteenth century and well into the nineteenth, but in general the high standing of Newtonian science protected it from rejection until supplanted by the physics of Mach, Poincaré and Einstein at the end of the nineteenth century. Knowledge and nature The new science that developed in the sixteenth and seventeenth centuries challenged the understanding of knowledge and how it may be obtained in a variety of ways. Thus, to take but one, though important, example, Copernicus’s suggestion that the earth rotates daily on its own axis and that in a year it circles the sun seemed quite at odds with our ordinary experience, where we see the sun rise in the east and set in the west and the earth itself feels stationary. Aristotle had himself stressed the empirical source of knowledge, and experience seemed to tell against Copernicus. Even if one granted that the Copernican system generated more accurate predictions, that in itself did not prove that it was true. Those who sided with Copernicus, like Copernicus himself, were often strongly impressed with the power of mathematics to make sense of the world, and often went so far as to see mathematics as itself providing a criterion for truth between competing theories. In England this position was well represented in the 1570s by John Dee’s Preface to the first English edition of Euclid’s Elements. Geometry, Dee claimed, provided a bridge between the eternal and the transient, the mind of God and the changing world. Mathematics provided the key to the creation. We have already seen that something of that was later to find expression in Galileo, as it did also in Galileo’s contemporary, the great astronomer, Kepler. This emphasis on the power of mathematics stood in contrast with the general scholastic position which did not emphasize mathematics as a source of knowledge of the natural world. Indeed, for the most part Aristotle’s natural philosophy rejected mathematics as irrelevant to understanding the truth about nature. Knowledge, it was held, was primarily a matter of identifying the true essence of natural kinds in terms of their essential properties by careful empirical investigation or, more often, mastering the truths that had been uncovered by the investigations of earlier thinkers, including, of course, Aristotle himself. According to Aristotle to have knowledge of a natural kind was to have arrived at a correct definition of that kind; to understand what a horse is, say, is to be able correctly to define the species. The rejection of Aristotle’s beliefs about the natural world was generally accompanied by rejection of his philosophy of science. And sometimes this included his understanding of what it was to explain something and his identification of the goal of enquiry with scientia, with known certain truth. Although central figures in the new approach to nature, of whom Francis Bacon, Galileo and Descartes are probably the most important examples, aspired to achieving certain knowledge in their enquiries, even Descartes saw that much of his account of the natural world should be regarded as reaching only some kind of high probability or ‘moral certainty’.21 In England in the period around the establishment of the Royal Society in 1660, there was clear recognition that it was too easy to claim more certainty for one’s science than was warranted. Boyle was just the leading figure in this circle, and his writings and practice provided a clear view of where he believed the limits of knowledge lay in matters of natural philosophy. A central concept in his account was that of hypothesis. Part of its force was to suggest something of the notion that the claim made by the hypothesis was to some degree problematic, though the precise amount was open to enormous variation. Its problematic nature was, though, to be seen in sharp contrast with the scientia claimed by the Aristotelians. The latter were therefore always liable to be labelled dogmatists, a charge that had for the new thinkers a quite definite pejorative sense nicely captured in the title of Joseph Glanvill’s defence of the new learning and its method, The Vanity of Dogmatising (1661). Granted that hypotheses were a part of normal scientific enquiry, it was also very much Boyle’s view that it was very easy, too easy, to assume as true something for which there was no substantial evidence. Something of this is to be found in his remarks about the Copernican theory of the universe. In an early letter Boyle complained of the dogmatic stances of the astronomers, ‘Ptolemeans, Tychonians and Copernicans…the one taking that…for an undeniable demonstration, which the other will absolutely reject as a paralogism, or at least call in question as no more than a bare probability’.22 At a later date Boyle made it clear that he regarded the Copernican system as a much superior hypothesis to the alternatives, because by it ‘divers inconveniences are avoided’ such as the assumptions by the Ptolemaic system of a firmament revolving about the earth at enormous speed every twenty-four hours, the need for epicycles to account for apparent retrograde motion, and so on.23 Similarly the corpuscular philosophy was an ‘hypothesis’ which was to be ‘either confirmed or disproved by, the historical truths [i.e. objective experimental facts] that will be delivered’.24 The contrast for hypotheses is with established empirical fact. And the gathering of such empirical data was the task of the natural philosopher. These were the histories of particular phenomena, the gathering of which Boyle, following Bacon, saw as the primary task of the virtuoso. Bacon had warned strongly against leaping to conclusions about the causes and nature of phenomena. In the Novum Organum (1620), his great work on scientific method that had such a high standing with the early Fellows of the Royal Society, he had argued that there are only two ways of searching into and discovering truth. ‘The one flies from the senses and particulars to the most general axioms, and from these principles, the truth of which it takes for settled and immovable, proceeds to judgement and to the discovery of middle axioms.’ This way, he says, is now in fashion, but the true way, as yet untried, ‘derives axioms from the senses and particulars, rising by a gradual and unbroken assent, so that it arrives at the most general axioms last of all’.25 The ‘histories’ of particular phenomena that Bacon recommended and Boyle was attempting to construct just were the evidence upon which the axioms might at a later stage be erected. One such work was The Experimental History of Colours (1663) in which Boyle tells us that of all the theories about the nature of light and colours, he is inclined to take colour to be ‘a modification of light: and would invite you chiefly to cultivate this hypothesis’. But he tells us that he proposes it only in a general sense and he does not pretend to choose between alternative views (one of which was Descartes’s theory of rotating particles). He goes on to say that he does not pretend to know what light is, which is itself required to be known if we are to know what colour is.26 In an interesting short note amongst his many manuscript papers now preserved at the Royal Society Boyle sets out ‘The Requisites of a Good Hypothesis’ and ‘The Qualities & Conditions of an Excellent Hypothesis’. For the former these include that it is intelligible, that it contains nothing impossible or manifestly false or that it supposes nothing unintelligible or absurd. It must be self-consistent and sufficient to account for the phenomena, and not contradict any other known phenomena. An ‘Excellent Hypothesis’ must in addition have sufficient grounds in the nature of things; it must be the simplest of all the good hypotheses we can frame; it must explicate the phenomena better than any other; and it should provide a basis for making predications which can be tested by experiment.27 Boyle’s requirements are not only of historical interest, but provide criteria which can as well be applied today. But they also reveal an important aspect of his approach to the natural world. Clearly Boyle did not aspire to the kind of science that begins from selfevident axioms and deduces consequences from these to produce a comprehensive account of nature. Equally clearly he did not reject a role for hypothetical explanation. But he did insist that not all hypotheses were equally acceptable, equally worthy of our attention. Very obviously, he wished to insist that there were rational criteria for choice, for theory choice, as philosophers of science might say today. Boyle, then, certainly cannot be accused of following a methodological path in science which some have seen as a fault in his mentor, Bacon, that of rejecting hypotheses as mere speculation and therefore unscientific. Many conjectures he no doubt did and would judge to be absurd. But this was because they failed to satisfy his criteria for good hypotheses and not because constructing hypotheses was itself pointless or worse. Nor, it need hardly be urged, did Boyle subscribe to any kind of dogmatic empiricism and a rejection of any role for reason in human enquiries. ‘Experience’, he wrote, ‘is but an assistant to reason, since it doth indeed supply information to the understanding; but the understanding remains still the judge.’28 Did Boyle believe that such enquiries would or could lead to knowledge? Precisely what epistemic status our judgements might be said to have is not something to which Boyle appears to have given us a direct answer, but it is fairly clear what his position was. He accepted that some things can be known to be true ‘immediately and by intuition’. He would no doubt have included simple arithmetic as an example. But he also saw it to be true of claims made on the basis of experience ‘as when by the bare evidence of the perception, [the mind] knows that this colour is red, and that other blue’.29 But in many cases, he goes on to explain, the intellect judges with the aid of hypotheses ‘such as are a great part of the theorems and conclusions in philosophy and divinity’.30 In other words, the certainty of our conclusions, which cannot exceed the certainty of the premises from which they are derived, can be no more sure than the hypotheses which they assume, and therefore at best only probable. But Boyle was prepared to settle for that state of affairs. He was not just ready to admit, but keen to underline, that there were many truths that were beyond the human mind to grasp. He saw no reason, he said, ‘that intelligibility to a human understanding should be necessary to the truth or existence of a thing, any more than that visibility to a human eye should be necessary to the existence of an atom, or of a corpuscle of air’.31 And although we may rightly smile at the Aristotelians for thinking they have explained the qualities of bodies with their theory of substantial forms, we must recognize that whilst it remains true that we can give no satisfactory account of how it is that sensible objects are perceived or how mind and body are connected, we are in no position to claim superiority.32 And in summary we may see in the following passage a reassertion of that Baconian position to which we have already referred. Men, he says, should be concerned ‘to make experiments and collect observations without being over-forward to establish principles and axioms, believing it to be uneasy to erect such theories, as are capable to explicate all the phenomena of nature, before they have been able to take notice of a tenth part of those phenomena’. He continues with words that were to be echoed in Locke’s Essay Concerning Human Understanding: it is sometimes conducive to the discovery of truth, to permit the understanding to make an hypothesis, in order to the explication of this or that difficulty, that by examining how far the phenomena are, or are not, capable of being solved by that hypothesis, the understanding, even by its own errors, be instructed.33 And again Boyle reminds us not to allow any hypotheses or systems that we do make to be regarded as so certain that we are not prepared to amend them in the light of further evidence. Boyle’s general approach to the possibility of knowledge of the natural world was to remain dominant for the remainder of the century and, with the fuller statement it was to receive in Locke’s Essay Concerning Human Understanding in 1690, the position was consolidated well into the Enlightenment. It also appeared to be endorsed by Newton’s methodology and by his pronouncements on method that appeared most overtly in the later editions of his works. Nor is this surprising when we remember that Boyle, Locke and Newton were, in their different areas, the leading intellectual figures of their time, united in their common commitment to the aspirations of the Royal Society. And Locke was a friend to both of them, as junior research partner to Boyle and his literary executor at his death, and as one of the few persons with whom Newton enjoyed a close personal and intellectual friendship.34 Newton’s most famous statement of his philosophy of science was set out in the Regulae Philosophandi of the second edition of the Principia of 1713.35 They appear to be a clear commitment to the empiricist account of natural science that we would expect from the President of the Royal Society. The first of the four embodies a principle of parsimony but which is qualified in an important way. The Rule reads: “We are to admit no more causes of natural things than such as are both true and sufficient to explain their appearances’.36 As explication Newton tells us that ‘Nature is pleased with simplicity, and affects not the pomp of superfluous causes’. Taken as a principle of parsimony and nothing more, reinforced by the second Rule which reads, ‘Therefore to the same natural effects we must, as far as possible, assign the same causes’, Newton’s first Rule seems unproblematic enough. But it is important to note, first, that the Rule takes it for granted that the task of natural philosophy is to seek for the causes of phenomena, and therefore takes the concept of causation to be unproblematic. Newton was hardly the first person to do that, but within two decades David Hume was to subject the concept of causation to a critical examination which remains a classic in philosophical analysis. Second, the Rule sets out two criteria which must be satisfied for the attribution of causes. It is not enough that the supposed causes explain the appearances, they must also be true. Newton does not tell us anything further about this, but it is easy enough to see what he had in mind. It was that the cause must not just be assumed to exist, there must be some evidence, and no doubt he had in mind empirical evidence, that the cause actually does exist. Thus, to take a simple example, if a ring disappears from a window sill by an open window, a sufficient explanation for its disappearance would be to assume that a magpie had taken it. But for Newton this would not count as a true explanation, unless we had some reason to believe that there was a magpie in the vicinity at the time. The ring’s recovery from a neighbouring magpie’s nest at a later stage, would be some (rather good) evidence that the supposed cause was the true one. It is almost certain that Newton had a particular philosophy of science in mind to which he was opposed when he formulated his Rule in this way, and that was what he took to be the philosophy of Descartes. At the end of his Principles of Philosophy, which gave a comprehensive explanation for many of the phenomena of nature and was a work that Newton knew well, Descartes had written in defence of his system that ‘if people look at all the many properties…and the fabric of the entire world, which I have deduced in this book from just a few principles, then, even if they think that my assumption of these principles was arbitrary and groundless, they will still perhaps acknowledge that it would hardly have been possible for so many items to fit into a coherent pattern if the original principles had been false’.37 It was Newton’s belief that we can make no such assumption. To do so would have been to accept an unwarranted hypothesis. As he expressed it in an important letter to Roger Cotes, it would be to accept ‘a proposition as is not a phenomenon nor deduced from any phenomena, but assumed or supposed— without any experimental proof’.38 He went on later in the same letter, ‘hypotheses of this kind, whether metaphysical or physical, whether of occult qualities or mechanical, have no place in experimental philosophy. In this philosophy, propositions are deduced from phenomena, and afterwards made general by induction’.39 This last comment, the reference to induction, takes us to the fourth Rule (we shall return to consider Rule III below). In it Newton says that we should look upon propositions inferred by general induction from phenomena as accurately or very nearly true, notwithstanding any contrary hypotheses that may be imagined, till such time as other phenomena occur by which they may either be made more accurate or liable to exceptions.40 Newton is claiming that the way to proceed in experimental philosophy, or, as we would now call it, empirical science, is to make observations and then draw general conclusions based on those observations. It is important that the general conclusions are based on observations and not just plucked from the air (the kind of hypotheses that Newton rejected). But for Newton it was equally important to recognize that it was perfectly legitimate to generalize on this basis, even though he realized that there was no absolute certainty guaranteed by the method. He explained this latter point very clearly near the end of the Queries in the Opticks: And although the arguing from experiments and observations by induction be no demonstration of general conclusions, yet it is the best way of arguing that the nature of things admits of, and may be looked upon as so much the stronger, by how much the induction is more general.41 Newton, then, saw inductive generalization as central to proper scientific explanation, and although he clearly recognized that it did not guarantee truth, it was the best way open to us for reaching general claims about the world. Once again it was David Hume who was to give critical attention to this central concept in Newtonian science. Newton’s invocation of the concept of gravitation in the Principia had quickly brought his theory under critical scrutiny. And it was Leibniz, and from a different direction, Berkeley, who were again Newton’s most important critics. Leibniz accused Newton of reintroducing occult qualities into philosophy because, Leibniz said, he was claiming that gravitation was the cause of the observed effects of bodies in motion, but gravity was only known by its effects and was therefore an unknown cause. In effect Leibniz was accusing Newton of just that intellectual sin that Newton himself so strongly opposed, namely assuming a cause without independent empirical evidence of its existence. The Rules of Reasoning were in part devised to meet such an objection, and it was Rule III in particular that was designed to do this. In it Newton says that the ‘qualities of bodies which admit neither intensification nor remission of degree, and which are found to belong to all bodies within the reach of our experiments, are to be esteemed the universal qualities of all bodies whatsoever’.42 In his explication of the Rule Newton again underlines his commitment to empirical evidence as the legitimate source for our claims about the properties of bodies, against ‘the dreams and vain fictions of our own devising’. And the qualities that we find in all bodies are, he says, those of extension, hardness, impenetrability, mobility and inertia, a list close to those primary qualities that we have already seen identified by Boyle and others. But Newton also points out that all bodies appear to gravitate towards one another, that is, all the objects that we come across have a tendency to move towards each other with increasing velocity. And this is an empirically identified property of all the bodies that we can investigate. But this property or tendency Newton says, is not claimed by him to be an essential property of matter. For it diminishes with distance, contrary to the first criterion for qualities in Rule III, namely, that it must not admit intensification or remission of degree. Still less was gravitation taken by Newton to be the cause of any action. And in many places Newton underlined that he did not have any sure explanation of the effect, the actual observed movement of objects towards each other. The Rules, then, may be seen as part of Newton’s deep commitment to the empirical approach to nature that he had early adopted and which not only found reinforcement in the success of his own enquiries but also in the philosophy of his friend, John Locke. But we also know that Newton sought an answer to that major question his account of motion raised, namely, what is it that causes objects to gravitate towards one another? Newton saw this as an issue related to several others, the nature and strength of chemical bonding, magnetic and electrical phenomena, for example, for which he had no satisfactory answer. But we have already seen that Newton was inclined to suspect that the cause of such observable forces in nature, such active principles, might be none other than the direct intervention of God himself. It was a conjecture, even an hypothesis, that Newton knew he was in no position to prove, and so he largely kept it to himself. NOTES 1 Cf. Epicurus Tetter to Herodotus’ passim [2.12]. 2 Cf. ‘The Assayer’ (1623) ([2.14], esp. 274–7). 3 Cf. Boyle’s biography of his early years in ‘The Life of the Hon. Robert Boyle’, [2.2], vol. I, xxiv. Boyle was scarcely 15 at the time. 4 Origin of Forms and Qualities, [2.7], 7. 5 ibid, 18. 6 [2.7], 51. 7 [2.7], 37. 8 [2.7], 32. 9 [2.17], 343. 10 [2.7], 185. 11 See, for example, [2.7], 198–90 for Boyle’s account of the creation and the principles required to maintain the world in being. 12 Cf. especially About the Excellency and Grounds of the Mechanical Hypothesis [2.7], 138– 54. 13 [2.3], 2:288–95. 14 [2.3], Newton to Richard Bentley, February 25 1692/3, vol. 3, 253–6. 15 Cf. B.J.T.Dobbs, [2.52]. 16 Opticks, Fourth Edition, 1730, [2.9], 400. 17 For a fuller discussion of More on space and time and his relationship to Boyle see A.Rupert Hall, [2.30], Chs 9 and 10. 18 Principia, bk III, [2.8], 545. 19 Cf. The Leibniz-Clarke Correspondence, [2.24], especially the Fifth Letter. 20 De Motu, sect. 63, [2.25], 4:49. BIBLIOGRAPHY Standard Editions 2.1 The Works of the Honourable Robert Boyle, ed. Thomas Birch, London, 5 vols, 1744. 2.2 The Works of the Honourable Robert Boyle, ed. Thomas Birch, new edn, London, 6 vols, 1772. 2.3 The Correspondence of Isaac Newton, ed. H.W.Turnbull, et. al., Cambridge, 7 vols, 1959–77– 2.4 Newton, Isaac Philosophiae naturalis principia mathematica, 1st edn, London, 1687, 2nd edn, 1713, 3rd edn, 1726. 2.5——Philosophiae naturalis principia mathematica, 3rd ed. 1726, with varient readings, ed. A.Koyré and I.B. Cohen, 2 vols, Cambridge, 1972. 2.6——Opticks, 1st edn, London, 1704, 2nd edn, 1717, 3rd edn, 1721, 4th edn, 1730. 21 See, for example, Descartes, Principles of Philosophy, part 4, sects 204 and 205, [2.16], 289– 90. 22 In a letter to Samuel Hartlib, 8 April 1647, [2.2], 1: xxxix. 23 Cf. The Second part of the Christian Virtuoso, [2.2], 6:722–3. 24 Origin of Forms and Qualities, [2.7], 18. 25 The New Organon, Aphorisms—bk I, XIX, [2.15], 261. 26 [2.2], I: 695. Samuel Pepys was a great admirer of this work of Boyle, though he claimed not to be able to understand it. 27 Cf. [2.7], 119. 28 The Christian Virtuoso (1690), [2.2], 5:539. 29 Advices in judging of Things said to transcend Reason, [2.2], 4:460. 30 [2.2], 4, 461. 31 [2.2], 4, 450. 32 Cf. The Excellence of Theology Compared with Natural Philosophy, [2.2], 4:45. 33 Certain Physiological Essays, [2.2], vol. 1, 302–3. Cf. Locke, An Essay Concerning Human Understanding, bk 4, ch. 12, sect. 13, [2.23], 648. 34 Not only did Newton go to stay with Locke at least twice at Oates in Essex but he invited Locke to visit him in London and in Cambridge. A favourite subject was their shared interest in theology and their secretly shared anti-trinitarian commitments. On their close intellectual position see, for example, Rogers, [2.58]. On Boyle and Locke see Rogers, [2.48]. 35 For accounts of the regulae and their place in Newton’s thought see A.Koyré, ‘Newton’s “Regulae Philosophandi” ’, [2.53], ch. 6, and G.A.J.Rogers, ‘Locke’s Essay and Newton’s Principia’, [2.59]. 36 Mathematical Principles of Natural Philosophy, [2.8], 2:398. 37 Principles of Philosophy IV, 205, [2.16], 1:290. 38 [2.3], 5:397. 39 Ibid. 40 [2.8], 400. 41 Opticks, [2.9], 404. 42 [2.8], 398. Other Editions 2.7 Selected Philosophical Papers of Robert Boyle, ed. M.A.Stewart, Manchester, Manchester University Press, 1979. 2.8 Newton, Isaac Mathematical Principles of Natural Philosophy and His System of the World, trans. Andrew Motte in 1729, rev. Florian Cajori, 2 vols, Berkeley and Los Angeles, University of California Press, 1962. 2.9——Opticks, New York, Dover, 1952. Bibliographies 2.10 Fulton, J.F. A Bibliography of the Honourable Robert Boyle, Clarendon Press, Oxford, 2nd edn, 1961. 2.11 Wallis, P. and R.Newton and Newtoniana, 1672–1975, Folkstone, W.Dawson and Sons Ltd, 1977. Important Primary Sources 2.12 Bacon, Francis The Philosophical Works of Francis Bacon, ed. J.M.Robertson from the text of Ellis and Spedding, London, George Routledge and Sons, 1905. 2.13 Berkeley, George The Works of George Berkeley, Bishop of Cloyne, ed. A.A. Luce and T.E.Jessop, 9 vols, London, Nelson, 1950–7. 2.14 Charleton, Walter Physiologia Epicuro-Gassendo-Charletoniana: or A Fabrick of Science Natural upon the Hypothesis of Atoms, Founded by Epicurus, Repaired by Petrus Gassendus, Augmented by Walter Charleton, London, 1654, repr. New York and London, Johnson Reprint Corporation, 1966. 2.15 Cudworth, Ralph The True Intellectual System of the Universe, London, 1678, repr. New York and London, Garland Press, 1978. 2.16 Descartes, R. The Philosophical Writings of Descartes, trans. John Cottingham, et al., Cambridge, Cambridge University Press, 3 vols, 1985–91. 2.17 Epicurus, The Extant Remains, trans. C.Bailey, Oxford, The Clarendon Press, 1926. 2.18 Galilei, Galileo ‘The Assayer’ (Il Saggiatore) in Discoveries and Opinions of Galileo, trans., with Introduction and Notes by Stillman Drake, New York, Doubleday Anchor Books, 1957. 2.19 Hobbes, Thomas The English Works of Thomas Hobbes, ed. Sir William Moleworth, 11 vols, London, 1839–45, repr., with an Introduction by G.A.J.Rogers, London and Bristol, Thoemmes Press/Routledge, 1992. 2.20 The Leibniz-Clarke Correspondence, ed. H.G.Alexander, Manchester University Press, Manchester, 1956. 2.21 Locke, John An Essay Concerning Human Understanding, London, 1690, 2nd edn, 1694, 3rd edn, 1695, 4th edn, 1700, 5th edn, 1706. 2.22——An Essay Concerning Human Understanding, ed. P.H.Nidditch, Oxford, Clarendon Press, 1975. 2.23 Lucretius, On Nature, trans. R.M.Geer, New York, Bobbs Merrill, 1965. 2.24 More, Henry A Collection of Several Philosophical Writings, London, 1662, repr. New York and London, Garland Press, 1978. 2.25——Enchiridion Metaphysicum, London 1671. Works on Science and Philosophy in Seventeenth- and Eighteenth-century Britain and Europe 2.26 Buchdahl, G. Metaphysics and the Philosophy of Science, Oxford, Black well, 1969. 2.27 Burtt, E.A. The Metaphysical Foundations of Modern Physical Science, Routledge and Kegan Paul, 2nd edn, London, 1932. 2.28 Clulee, N.H. John Dee’s natural Philosophy. Between Science and Religion, London, Routledge, 1988. 2.29 Debus, A.G. The English Paracelsians, London, Oldbourne, 1965. 2.30 Hall, A.R. Henry More. Magic, Religion and Experiment, Oxford, Blackwell, 1990. 2.31 Kargon, R.H. Atomism in England from Hariot to Newton, Oxford, Clarendon Press, 1966. 2.32 McMullin, E. (ed.) the Concept of Matter in Modern Philosophy, Notre Dame and London, University of Notre Dame Press, 1978. 2.33 Oldroyd, D. The Arch of Knowledge. An Introductory Study of the History of the Philosophy and Methodology of Science, New York and London, Methuen, 1986. 2.34 Osier, M. (ed.), Atoms, Pneuma, and Tranquility. Epicurean and Stoic Themes in European Thought, Cambridge, Cambridge University Press, 1991. 2.35 Schofield, R.E. Mechanism and Materialism. British Natural Philosophy in an Age of Reason, Princeton, Princeton University Press, NJ, 1970. 2.36 Shapiro, B.S. Probability and Certainty in Seventeenth-Century England, Princeton, Princeton University Press, NJ, 1983. 2.37 van Leeuwen, H.G. The Problem of Certainty in English Thought. 1630–1690, The Hague, Martinus Nijhoff, 1970. 2.38 Webster, C. The Great Instauration. Science, Medicine and Reform 1626–1660, London, Duckworth, 1975. 2.39 Yolton, J.W. (ed.) Philosophy, Religion and Science in the Seventeenth and Eighteenth Centuries, Rochester and Woodbridge, University of Rochester Press, 1990. Works on Robert Boyle 2.40 Alexander, P. ‘Boyle and Locke on Primary and Secondary Qualities’, Ratio 16 (1974): 237–55. 2.41 Alexander, P. Ideas, Qualities and Corpuscles. Locke and Boyle on the External World, Cambridge, Cambridge University Press, 1985. 2.42 Hall, A.R. and Hall, M.B. ‘Philosophy and Natural Philosophy, Boyle and Spinoza’, in I.B. Cohen and R.Taton (eds), Mélanges Alexandre Koyré. L’aventure de l’esprit, Paris, 1964, pp. 241–56. 2.43 Jacob, J.R. ‘Boyle’s Atomism and the Restoration Assault on Pagan Naturalism’, Social Studies in Science 8 (1978): 211–33. 2.44 Macintosh, J.J. ‘Robert Boyle on Epicurean Atheism and Atomism’ in [2.34]. 2.45 Mandelbaum, M. Philosophy, Science and Sense Perception, Baltimore, Baltimore University Press, 1964. 2.46 McGuire, J.E. ‘Boyle’s Conception of Nature’, J. of the History of Ideas 33 (1972): 523–42. 2.47 O’Toole, F.J. ‘Qualities and Powers in the Corpuscular Philosophy of Robert Boyle’, J. of the History of Philosophy 12 (1974): 295–315. 2.48 Rogers, G.A.J. ‘Boyle, Locke and Reason’, J. of the History of Ideas XXVII: 206– 16, repr. in [2.39]. 2.49 Shapin, S. and Schaffer, S. ‘Leviathan’ and the Air-Pump. Hobbes, Boyle and the Experimental Life, Princeton, Princeton University Press, 1985. Works on Isaac Newton 2.50 Austin, W.H. ‘Isaac Newton on Science and Religion’, J. of the History of Ideas XXXI (1970): 521–42. 2.51 Butts, R.E. and Davis, J.W. The Methodological Heritage of Newton, Oxford, Blackwell, 1970. 2.52 Dobbs, B.J.T. ‘Stoic and Epicurean Doctrines in Newton’s System of the World’ in [2.34]. 2.53 Hall, A.R. Philosophers at War. The Quarrel between Newton and Leibniz, Cambridge, Cambridge University Press, 1980. 2.54 Koyré, A. Newtonian Studies, London, Chapman, 1968. 2.55 Kubrin, D.C. ‘Newton and the Cyclical Cosmos. Providence and the Mechanical Philosophy’, J. of the History of Ideas 28 (1967): 325–46. 2.56 McGuire, J.E. ‘Atoms and the “Analogy of Nature”. Newton’s third Rule of Philosophizing’, Studies in the History and Philosophy of Science 1 (1970): 154–208. 2.57 McGuire, J.E. and Tamny, M. Certain Philosophical Questions. Newton’s Trinity Notebook, Cambridge, Cambridge University Press, 1983. 2.58 Rogers, G.A.J. ‘The Empiricism of Locke and Newton’ in S.C.Brown (ed.) Philosophers of the Enlightenment, Brighton, Harvester Press, 1979, pp. 1–30. 2.59——‘Locke’s Essay and Newton’s Principia’, J. of the History of Ideas 39 (1978): 217–32. Repr. in [2.39]. 2.60 Westfall, R.S. ‘The Foundations of Newton’s Philosophy of Nature’, British J. for the History of Science, 1 (1962): 171–82. 2.61——Force in Newton’s Physics, the Science of Dynamics in the Seventeenth Century, London, Macdonald and New York, American Elsevier, 1971. 2.62——Never at Rest. A Biography of Isaac Newton, Cambridge, Cambridge University Press, 1980.