Jacques Maritain Center: Thomistic Institute

The Scientific Revolution and Contemporary Discourse on Faith and Reason

Thomistic Institute, University of Notre Dame
16-23 July 1999

William E. Carroll

Aristotelian physics made sense of the world and strengthened the hands of the men of God and all those striving to redeem civilization, culture, and truth from barbarism There was only one problem. It was wrong.(1)

In early June of this year, when Pope John Paul II addressed a meeting of Polish academics at the new University of Copernicus, he observed that Copernican astronomy, especially its defense in the Seventeenth Century by scientists such as Galileo, reminds us of an "ever-present tension between reason and faith." The Pope noted that although Copernicus saw his new astronomical system as "giving rise to even greater amazement at the Creator of the world and the power of human reason, many people took it as a means of setting reason against faith." Coincident with the rise of modern science in the Seventeenth and Eighteenth Centuries, there was, according to the Pope, a tragic split between reason and faith. "Particularly, beginning in the Enlightenment period, an extreme and one-sided rationalism led to the radicalization of positions in the realm of the natural sciences and in that of philosophy. The resulting split between faith and reason caused irreparable damage not only to religion but also to culture."(2) The Pope called upon his audience to work for "a reconciliation between faith and reason,"(3) and remarked that, "it is quite important to remember constantly that authentic freedom of scientific research cannot prescind from the criterion of truth and goodness."

Interpretations of modernity, including the understanding of the relationship between faith and reason, depend in important ways on analyses of the Scientific Revolution of the Seventeenth Century. In particular, the materialism, mechanism, and reductionism so often associated with modern science has its roots in a faulty philosophy of nature supported by an interpretation of the history of science.(4) The understanding of the rise of modern science as involving a rejection of Aristotelian science (5) has led many to ignore the profound truths about nature, human nature, and God which are found in Aristotelian and Thomistic thought. There are related interpretations of the Scientific Revolution which see it as an emancipation of science from the clutches of theology: interpretations which provide considerable support for view that reason and faith are bitter enemies, or for the view recently dubbed NOMA by Stephen J. Gould.(6) According to Gould, reason and faith properly exercise "non-overlapping magisteria" and it was Galileo who led the way for the modern recognition of these distinct magisteria.

As we look at the importance of the history of science in contemporary discourse on faith and reason, I want to begin with a conclusion: the developments in the natural sciences in the Seventeenth Century, most apparent in the field of physics, do not so much represent a rejection of the principles of Aristotelian physics(7) as they mark a great advance in our understanding of the ways in which mathematics can be applied to the study of physical reality. The sciences of Galileo and Newton, strikingly original as they are, remain fully consistent with a general Aristotelian science of nature. There is, of course, much more to the developments of science in the Seventeenth Century than the role played by mathematics as applied to motion. Nevertheless, by keeping this focus we will have an opportunity to pursue with appropriate sophistication an understanding of the Scientific Revolution.

Let us turn to a characteristic rendering of what we might call the master narrative of the Scientific Revolution. Herbert Butterfield, writing more than forty years ago in a book entitled The Origins of Modern Science (1957), remarked that because the Scientific Revolution:

. . . overturned the authority in science not only of the Middle Ages but of the ancient world, . . . since it ended not only in the eclipse of scholastic philosophy but in the destruction of Aristotelian physics, it outshines everything since the rise of Christianity and reduces the Renaissance and Reformation to the rank of mere episodes, mere internal displacements, within the system of medieval Christendom. Since it changed the character of men's habitual operations even in the conduct of the non-material sciences, while transforming the whole diagram of the physical universe and the very texture of human life itself, it looms so large as the real origin of the modern world and of the modern mentality that our customary periodisation of European history has become an anachronism and an encumbrance.(8)

Although we may be less enthusiastic than Butterfield in his characterization of the importance of the Scientific Revolution, we ought to recognize in his comments the prevailing view of the Scientific Revolution as the overthrow of Aristotelian science. We may well accept Thomas Kuhn's description of this Revolution as a "paradigm shift" and thus react skeptically to claims which conclude that Aristotle's science was false and modern science true, but nevertheless the master narrative remains intact, since, in Kuhn's terms, there is an incommensurability between the old and the new paradigms.

The master narrative tells the story of how Galileo and Newton overturned the antiquated Aristotelian view of the universe and established the principles of modern science. The very first principle of the new physics is the principle of inertia: "Every body perseveres in its state of rest or of uniform motion in a straight line, unless it is compelled to change that state by forces impressed upon it." Alfred North Whitehead called the principle of inertia "the first article of the creed of science, and like the Church's creed it is more than a mere statement of belief; it is a paean of triumph over defeated heretics."(9) The defeated heretics, Whitehead explains, are "the Aristotelians who for two thousand years imposed on dynamics the search for a physical cause of motion."(10)

Contemporary commentary on the relationship between theology and the natural sciences has been heavily influenced by the orthodox interpretation of the Scientific Revolution as a radical rupture in the history of science. Anthony Kenny, for example, denies the probative force of Aquinas' proofs for the existence of God because these proofs are based on the principles of Aristotelian science, a science which the modern world has shown to be false.(11) Kenny also thinks Aquinas' ethical theory suffers because Aquinas' account of appetites in man and in animals depends upon an "archaic physics," now known to be false. Any notion of the natural agency of inanimate matter cannot be reconciled with the principle of inertia. Newtonian mechanics, according to Kenny, rules out any appeal to a teleological account of all of nature.(12) Kenny observes that, for Aquinas, "all action, including the most elemental actions of completely inanimate bodies , was . . . fundamentally teleological. This part of Aquinas' system is something which must be discarded if we are to make any use of his philosophy at the present time."(13)

One particularly influential contemporary theologian, Wolfhart Pannenberg, claims that the acceptance of the principle of inertia in the Seventeenth Century represents not only a radical break in the history of science but is also a fundamental problem for the Christian doctrine of creation. According to Pannenberg, the principle of inertia lies behind a denial of the radical contingency of the world: a contingency central to the doctrine of creation.(14) For Pannenberg, it is not until the ascendancy of field theory in contemporary physics that we can discern a complementarity between the claims of physics and the theological concept of creation.(15)

Pannenberg observes that, especially with Descartes, the principle of inertia "leads to an emancipation of the natural processes from their dependence on God, . . . [even though] the general framework of Descartes' ideas on the creation of the world and on its [the world's] need for continuous preservation by God was still quite traditional."(16) It was Descartes who referred to inertia as "the first law of nature."(17) Descartes did take the law of inertia to be a manifestation of the immutability of God, but the seeds are sown, according to Pannenberg, for the eventual affirmation of the autonomy of the world and its processes.(18) It was Newton's understanding of inertia in terms of a force that is inherent in bodies, along with the reduction of force to a body and its mass, that contributed in a decisive way "in the course of the eighteenth century to the removal of God from the explanation of nature."(19)

The emancipation from the creator God entailed in the principle of inertia did not apply only to natural bodies and beings which at the same time continued to undergo influences from outside themselves. Even more serious was the consequence that the system of the natural universe had to be conceived now as an interplay between finite bodies and forces without further need for recourse to God.(20)

The source of Pannenberg's understanding of the importance of the principle of inertia for the Christian doctrine of creation is the work of another German thinker, Hans Blumenberg. In two major books, The Legitimacy of the Modern Age, and The Genesis of the Copernican World, Blumenberg ranges widely in philosophy, the natural sciences, theology, political thought, and literature as he examines the transition from the medieval to the modern world. For Blumenberg, the novelty of modernity is to be found in what he calls the "reoccupation" of prior explanations of man, nature, and God.

Let me offer an example of what Blumenberg means. The modern commitment to human autonomy and self-assertion [Selbsterhaltung] is, for Blumenberg, a response to the claims of divine omnipotence, of the absolute power of God, characteristic of Nominalist thought. Such affirmation of divine omnipotence necessarily entailed a denial of an intelligible order of nature discoverable by human reason. The utter contingency of a world dependent upon the absolute will of God is, according to Blumenberg, "a disappearance of order [Ordnungsschwund]" which causes doubt "regarding the existence of a structure of reality that can be related to man" and makes the traditional conception of human activity bound up in the ancient and medieval cosmos no longer workable.(21) Blumenberg notes: "The modern age has regarded self-preservation (conservatio sui) as a fundamental category of everything in existence and has found this borne out all the way from the principle of inertia in physics to the biological structure of drives and the laws of state building."(22)

Blumenberg thinks that the early modern mechanistic explanation of nature, with its commitment to "absolute matter," re-occupies the position of the late medieval Nominalist mode of explanation based on an absolute divine will.(23) Self-assertion and human autonomy are the broader cultural correlatives of a fundamentally new principle of explanation -- and, for Blumenberg, it is the principle of inertia which lies at the core of this new view of things. With the principle of inertia, there is in all things, in all matter, that is, an inherent force of self-preservation [a vis insita]. Consequently, a "transcendent conservation [Fremderhaltung] of nature becomes indeed superfluous. In a similar way, the transfer of movement renders the assumption of a divine cooperation in the activities of creatures superfluous. Thus deism must be seen as the consequence of the principle of inertia in modern physics."(24)

The incompatibility between the principle of inertia and the doctrine of creation, which Blumenberg and Pannenberg see as a characteristic feature of the modern age, rests upon a misunderstanding of creation. In their analysis, creation is really a kind of change, and the creator functions as one more agent not fundamentally different from other agents in the world of change. Both will speak of God as a transcendent agent, but God's creative actions in the world are causes which differ only in degree from other efficient causes. God's role as unmoved mover, for example, is necessary for medieval Aristotelian physics because the science of nature requires God's agency in order to explain motion. Thus, Blumenberg and Pannenberg think that an appeal to God's agency is irrelevant -- or at least is seen to be irrelevant - - in a world operating according to the principle of inertia. As Blumenberg says, God's function as conserver of the natural world is rendered superfluous. No longer is the continuing existence of any given state of affairs in need of explanation, but only the occurrence of any change of this state.

An important error in this analysis, as I have suggested, is to consider creation as a kind of change. You will remember that throughout his discussion of creation Aquinas was always careful to point out that creation is not a change; rather, it is a metaphysical dependence in the order of being. This metaphysical dependence is the same throughout the being's existence as it is at its beginning. The traditional doctrine of creation remains unaffected by any conclusion in the natural sciences, since creation is a metaphysical notion not a physical one.

Blumenberg's and Pannenberg's analysis of the impact of the principle of inertia on the doctrine of creation has its roots in their acceptance of the standard interpretation of the Scientific Revolution as a rejection of Aristotelian physics.

If there is a fundamental incompatibility, or incommensurability, between Aristotelian science and modern science, then any theological or philosophical reflection rooted in or employing principles from Aristotelian science must either be rejected or radically reformulated. Often I participate in conferences on the relationship between religion and science in which speakers refer to the "Newtonian settlement" as the basis for modern philosophy and theology.(25) This "settlement" tends to rule out appeals to Aristotelian and Thomistic natural philosophy since, so the argument goes, such a philosophy of nature has been rendered false(26) by modern science. This helps to explain why in the Seventeenth and Eighteenth Centuries it was apparent to many that only a mechanistic philosophy of nature could meet the evidence of modern science. Indeed, early proponents of mechanism, especially in the Seventeenth Century, saw in it a way to reconcile their belief in God with the insights of Newtonian science. More frequently today process thought is urged as providing the necessary philosophical complement to the natural sciences. Form and matter, substance and accident, teleology and the like are thus all seen as part of a view of the world which, thanks to the Scientific Revolution, we know is wrong.

Nowhere is the rejection of Aristotelian physics more evident, so the master narrative of the Scientific Revolution would have it, than in the principle of inertia, which, so it seems, directly contradicts the fundamental Aristotelian principle that everything that is moved is moved by another.(27) If we turn to the principle of inertia and examine it in some detail we can find evidence against the view that to accept modern science one must reject Aristotelian natural philosophy.

Newton's famous three laws of motion appear early in the Principia. He begins with a series of definitions concerning mass, forces, and the like; then states the three laws and deduces corollaries from them. These laws, corollaries, and definitions are expressed in expository prose without those mathematical equations with which we have become familiar. In the preface, Newton reminds the reader of that in this work he will "subject the phenomena of nature to the laws of mathematics." At another place, he observes that he only provides "a mathematical notion of . . . forces, without considering their physical causes."(28) He tells us that he is considering ". . . forces not physically, but mathematically."(29) At the beginning of Book III, the section called the "System of the World," Newton notes: "In the preceding books, I have laid down principles not philosophical but mathematical."(30) When he turns to discuss various explanations of planetary movement, he notes the ancient view of the planets' being imbedded in solid orbs. Newton thinks that Descartes and Kepler postulated celestial vortices as a way to account for such motion, and then he comments: "From the first law of motion it is very certain that some force is required. [But] [o]ur purpose is to bring out its quantity and properties and to investigate mathematically its effects on moving bodies."(31)

Although Newton was convinced of the tremendous power of mathematics to discover and describe accurately certain fundamental characteristics of the world, we must not think that Newton was some 17th century Pythagorean for whom the mathematical description of reality is the only truly scientific account of nature. Newton warns against such an attribution when he remarks:

. . . those violate the accuracy of language, which ought to be kept precise, who interpret these words [time, space, place, and motion] for the measured quantities. Nor do those less defile the purity of mathematical and philosophical truths, who confound real quantities with their relations and sensible measures.(32)

Immediately prior to his enunciation of the principle of inertia, Newton provides a definition of centripetal force in which he hypothesizes what would happen in projectile motion "if the resistance of the air is taken away." In this discussion Newton moves from the world of ordinary experience to imagine the limiting case of motion: viz., that at which the projectile would proceed in its motion forever. Newton describes what obtains in a limiting case, and, thus, he presupposes the concept of limit in the derivation of that case. Newton's notion of limit is drawn from mathematical modes of reasoning. It is precisely such a mathematical concept of limit which is at the root of the principle of inertia. The principle is an inference drawn from the mathematical-physical approach to a limit. In other words, as the resistance of the medium approaches zero, the distance traveled approaches infinity.(33)

As an idealized, quasi-mathematical concept, the principle of inertia involves an abstraction from the extrinsic forces acting on real bodies moving in a physical environment. The principle also involves an abstraction from any kind of physical causality. Accordingly, the principle of inertia, regardless of its truth, says nothing in support of nor in contradiction to Aristotle's principle in physics that everything that is moved is moved by another. Only if one assumes that the principle of inertia is a law of nature and not simply a principle in mathematical physics would one have a problem with its relationship to Aristotelian physics.(34)

The principle of inertia considers bodies simply as three- dimensional realities devoid of natures. Newton's first law of motion cannot be a "law of nature," least of all the prima lex naturae that Descartes thought necessary in his universe of geometrical space. Only in such a Cartesian world of "nude bodies," each with a fixed "quantity of matter" and a fixed "quantity of motion," can there be such a first law of nature.(35) The Cartesian world, however, is not Newton's world, and Descartes' notion of inertia is not Newton's.

If the real world is actually a world of natures, of qualitative distinctions, and of intrinsic principles of spontaneous behavior, there would be no problem in abstracting from such a world to consider only the quantitative features of things. The scientific study of such abstracted reality we should recognize as mathematical physics, the principles of which are different from those of other sciences.

The application of mathematics to the study of motion necessarily involves an abstract world. And an abstract world is not a false world; but nor is it identical with the world of nature. Newton knew full well that when, for example, he defined "mass" as "the quantity of matter" and "momentum" as the "quantity of motion," that he was proceeding in the realm of mathematical physics. We should take a clue from the title of his work: Mathematical Principles of Natural Philosophy [Philosophiae Naturalis Principia Mathematica], which differs significantly from Descartes' title, Principles of Philosophy. Along with James Weisheipl and William Wallace, whose analyses have influenced my work significantly,(36) we should recognize that in Newton there is not so much a rejection of the principles of Aristotelian physics as a great expansion of and sophistication in the science of mathematical physics.(37) (38)

As Thomas Aquinas points out,(39) the natural sciences study what exists in matter and in motion precisely as these things exist in matter and motion. Man cannot be studied, as man, distinct from flesh and bones. Man cannot be understood without his materiality. Mathematics studies those dimensions and quantities which exist in sensible matter, but which can be known separate from sensible matter. Man, through a special process of abstraction on the part of his intellect, has the capacity to understand shapes and numbers independently from the material bodies in which they exists. Mathematics and the natural sciences can be distinguished in terms of their respective objects of study, as well as in terms of the different ways in which the objects are known.(40)

Mathematics does not provide a deeper explanation of the world of nature than does physics; nor does mathematics provide the true principles of scientific inquiry for the natural sciences. Thus, the natural sciences have an autonomy appropriately their own.(41)

Although mathematics and physics are autonomous and distinct sciences, one may apply mathematical principles to the study of natural phenomena. Such applications occur in neither the science of mathematics, nor in physics. They constitute mixed sciences: types of knowledge that are intermediate between what we today might term "pure" mathematics and a more general science of nature. Aristotle, in the second book of the Physics, recognizes the legitimacy of such intermediate sciences, what he considers to be in some sense branches of mathematics which come nearest to the study of nature: optics, harmonics, and astronomy. Referring to such a mixed science, Aquinas writes: "it does not belong to the mathematician to treat of motion, although mathematical principles can be applied to motion. . . . The measurements of motions are studies in the intermediate sciences between mathematics and natural science."(42)

The application of mathematical principles to the study of natural phenomena is never a substitute for the science of physics which has as its object the study of physical bodies in their full reality. Principles of mathematics, although applicable to the study of natural phenomena, cannot explain the causes and true nature of natural phenomena.

It seems to me(43) that we can best understand the history of science in the fourteenth through the seventeenth centuries -- and, indeed, beyond to our own time -- if we recognize that some of the greatest accomplishments in the sciences have taken place in mathematical physics -- that intermediate science between mathematics and physics. The careful distinctions drawn by Albert the Great and Thomas Aquinas frequently have been lost in the midst of the great advances mathematical physicists have achieved: the confusion is already in Descartes, who, as we have seen, called inertia the first law of nature, rather than recognizing it, as Newton did, as a mathematical principle of natural philosophy.

Once we understand the nature of mathematics, physics, and the intermediate sciences -- an understanding present in the thought of Aristotle, and made explicit especially by Thomas Aquinas -- then, I think, we can see a fundamental continuity in the history of science from the time of Aristotle to the present. Although ancient and mediaeval thinkers were not very concerned with what is called "mathematical physics," and they surely did not expect such a fruitful expansion of the role of mathematics in describing the world of nature, still, they did recognize the validity of the use of mathematics in investigating nature. Such a perspective on the Scientific Revolution frees us from the false view that one must chose between Aristotle and the great advances of modern science. We would also be emancipated from the false exaggeration of the importance of mathematics, an exaggeration which has encouraged many to force all the sciences -- natural and social -- into the Procustean bed of mathematics, belittling or tending to ignore what cannot be timed, weighed, measured, or counted.(44)

The philosophical baggage of a mechanistic and materialistic natural philosophy which is often associated with modern science is the product of philosophical traditions in the Seventeenth Century and beyond. Mechanism and materialism represent a radical rejection of Aristotelian and Thomistic natural philosophy, but mechanism and materialism remain excess baggage, not required in order to accept the advances in our understanding of the world which are the legacy of Galileo and Newton. Although many historians, philosophers, and theologians see modern science as providing, ultimately, a challenge to the God of traditional religion, such a judgment rests on questionable interpretations of the Scientific Revolution as well as on a failure to appreciate the theological and philosophical heritage of the Middle Ages.

Remember the Pope's remarks to the Polish academicians last June, that "authentic freedom of scientific research cannot prescind from the criterion of truth and goodness." Modern science seen as a rejection of Aristotelian physics is often viewed as being opposed to any notion of the good discoverable in nature. Or, at most, science must remain, as Stephen Gould claims, irrelevant to questions about "God, meaning, and morality."(45) I suppose it is not strange that once purpose, meaning, and finality are excluded from nature, then the postmodern denial of truth in science should find a hearty welcome.

Misinterpretations of the Scientific Revolution may have also tempted some in the Thomistic tradition to retreat from the arena of natural philosophy to bask in the seemingly safer and ethereal realm of metaphysics. The history of science can help us distinguish among the advances of modern science, the mechanistic and materialist natural philosophy which has accompanied these advances, and the principles of Thomistic natural philosophy which can lead to a deeper and more completed understanding of nature, human nature, and God.(46)


1. Charles Gillispie, The Edge of Objectivity: An Essay in the History of Scientific Ideas (Princeton University Press, 1960), p. 13. Gillispie is the general editor of the Dictionary of Scientific Biography (1980).

2. Pope John Paul II, "Address at Meeting with Rectors of Academic Institutions: Torun, Monday, 7 June 1999," Vatican Web Site.

3. "Deprived of reason, faith has stressed feeling and experience, and so run[s] the risk of no longer being a universal proposition. It is an illusion to think that faith, tied to weak reasoning, might be more penetrating; on the contrary, faith then runs the grave risk of withering into myth or superstition. By the same token, reason which is unrelated to an adult faith is not prompted to turn its gaze to the newness and radicality of being. This is w hy I make this strong and insistent appeal . . . that faith and philosophy recover the profound unity which allows them to stand in harmony with their nature without compromising their mutual autonomy." Fides et Ratio, 48. The Pope locates in the late Middle Ages an increasingly "fateful separation" between faith and reason which ultimately led some to espouse the cause of "rational knowledge sundered from faith and meant to take the place of faith." The Pope argues that such a separation led to an "ever deeper mistrust of reason itself." Gradually "[i]n the field of scientific research," the Pope writes, "a positivistic mentality took hold which not only abandoned the Christian vision of the world, but more especially rejected every appeal to a metaphysical or moral vision." The Pope sees nihilism as the ultimate outcome of this "crisis of rationalism." "As a philosophy of nothingness, it has a certain attraction for people of our time. Its adherents claim that the search is an end in itself, without any hope or possibility of ever attaining the goal of truth. In the nihilist interpretation, life is no more than an occasion for sensations and experiences in which the ephemeral has pride of place. Nihilism is at the root of the widespread mentality which claims that a definitive commitment should no longer be made, because everything is fleeting and provisional." ibid.

4. More than twenty-five years ago, the French biologist Jacques Monod remarked: "Anything can be reduced to simple, obvious, mechanical interactions. The cell is a machine; the animal is a machine; man is a machine." (Jacques Monod, Chance and Necessity: An Essay on the Natural Philosophy of Biology. New York: Knopf, 1974, p. ix) Or consider the well-known comment by Richard Dawkins, author of The Selfish Gene, who claims that a human being is not a cause but an effect, and that life and mind are merely the outcome of genes that "swarm in huge colonies, safe inside gigantic lumbering robots."(Richard Dawkins, The Selfish Gene, New York: Oxford University Press, 1976, p. 21) In River Out of Eden: A Darwinian View of Life, Dawkins is not afraid to draw the following conclusion: "The universe we observe has precisely the properties we should expect if there is, at bottom, no design, no purpose, no evil and no good, nothing but blind pitiless indifference. . . . DNA neither knows nor cares. DNA just is. And we dance to its music." (New York: Basic Books, 1995, p. 133) Sir Francis Crick, co- discoverer of the double-helix structure of the DNA molecule, writes at the beginning of The Astonishing Hypothesis: "The Astonishing Hypothesis is that 'You,' your joys and your sorrows, your memories and your ambitions, your sense of personal identity and your free will, are in fact no more than the behavior of a vast assembly of nerve cells and their associated molecules." (New York: Scribner, 1994)

5. The commonly accepted narrative of the Scientific Revolution, whether we accept Pierre Duhem's claim for a radical change in fourteenth century Paris or Anneliese Maier's argument that the principle of inertia, set forth in the seventeenth century, is fundamentally at odds with the Aristotelian principle that everything that is moved is moved by another, sees a fundamental discontinuity in the history of science which heralds the birth of modern science. Recently several historians of science have suggested that we ought to move beyond the categories of continuity and discontinuity in examining the history of science, in general, and the Scientific Revolution, in particular. This view is especially apparent in the increased interest in the social history of science, and is associated with broader questions concerning the sociology of knowledge. In Disciplining Experience: The Mathematical Way in the Scientific Revolution (1995), Peter Dear writes: "The issue of the 'influence' of medieval scholastic thought on the Scientific Revolution has ceased to be as pressing as it once was. Firmly rooted in untenable historiographical assumptions concerning 'scientific method,' and directed towards particular apologetic ends whereby the prize went to the originators of that method, it nowadays lacks cogency. . . . That those usually seen as standing in the forefront of the development of new approaches to nature and knowledge in the seventeenth century were acquainted with, and intellectually shaped by the 'learning of the schools' is surely an unquestionable proposition. But to formulate its meaning in terms of either an essential 'continuity,' however qualified, or a 'discontinuity' is unnecessary and unilluminating. What is called for is an understanding of the intellectual culture within which new ideas and manners of formulating knowledge made sense in the seventeenth century in ways that they had not before. If we can identify specific changes of this sort, and then locate their contemporaneous meanings, we will also be able to ask questions about the means by which they came about. It is the purpose of this book to investigate one such change." (p. 15) What Dear has done is simply to have substituted a concern for one set of continuities and discontinuities for another! We can see in his characterization of the search for "essential 'continuities'" another feature of social history: the rejection of any concern for essences. See also, Steven Shapin, The Scientific Revolution (University of Chicago Press, 1996).

For an excellent survey of various interpretations of the Scientific Revolution, see H. Floris Cohen's The Scientific Revolution: A Historiographical Survey (1994). David Lindberg's introductory essay on conceptions of the Scientific Revolution in D. Lindberg and R. Westman (eds.), Reappraisals of the Scientific Revolution (1990) is also excellent.

6. Stephen J. Gould, Rocks of Ages: Science and Religion in the Fullness of Life (New York: Ballantine Publishing Group, 1999).

7. Here it is important to distinguish between the principles which inform Aristotle's science of nature, principles set out in his Physics, Posterior Analytics, On the Generation of Animals, De Anima, and the like, and particular conclusions which Aristotle reached, such as that Earth is immobile and at the center of the universe; or other conclusions he supported in cosmology in De Caelo.

8. The Origins of Modern Science (New York: The Free Press, 1965 [revised edition]), pp. 7-8.

9. Essays, pp. 234-5. This analysis depends significantly on the work of James Weisheipl, especially as found in Nature and Motion in the Middle Ages (1985), which I edited.

10. ibid., p. 235.

11. ". . . it seems that Newton's law [of inertia] wrecks the argument of the First Way. For at any given time, the rectilinear uniform motion of a body can be explained by the principle of inertia in terms of the body's own previous motion without any appeal to any other agent. And there seems [to be] no a priori reason why this explanatory process should not go backwards for ever. Newton's law will not explain how motion began; but how do we know that motion had a beginning?" Anthony Kenny, The Five Ways: St. Thomas Aquinas' Proofs of God's Existence (New York: Shocken Books, 1969), p. 28.

12. "[T]he operations of the laws of inertia and gravity and the natural activities of sulphur or uranium are not teleological activities at all. If we today are to seek, as Aquinas did, to locate animal desire and human willing in a hierarchy of different kinds of tendencies towards good, then we must put at the bottom level of the hierarchy not the natural agency of inanimate matter, but the non-conscious teleological activities to be found in the plant world." Anthony Kenny, Aquinas on Mind. London: Routledge, 1993, p. 61.

13. ibid. Alisdair MacIntyre, despite his sympathies for Aristotle and Aquinas, argues for the necessity of providing a new foundation for ethics, different from the natural philosophy of Aristotle and Aquinas, by pointing to the encounter between impetus theory and the inertial physics of Galileo and Newton, which encounter he calls a classic case of "systematically different and incomparable observational languages, key concepts, and theoretical structures [which] were framed in terms of rival and incomparable standards . . . [such that] there was no shared common measure [between the two physical systems]." Alisdair MacIntyre, Three Rival Moral Theories, p. 118. Italics added.

14. Pannenberg: "any contemporary discussion regarding theology and science should first focus on the question of what modern science, and especially modern physics, can say about the contingency of the world as a whole and every part in it." Wolfhart Pannenberg, "The Doctrine of Creation and Modern Science," Zygon 23.1 (March 1988), p. 9. For an excellent analysis of Pannenberg's position on contingency, see Robert John Russell, "Contingency in Physics and Cosmology: A Critique of the Theology of Wolfhart Pannenberg," Zygon 23.1 (March 1988), pp. 23-43. This entire issue of Zygon is dedicated to the work of Pannenberg.

15. In an introduction to Pannenberg's Toward a Theology of Nature, Ted Peters describes Pannenberg's position in the following way: "The relationship between uniform laws of nature and the contingency of particular events provides the formal point of departure for Pannenberg's theological analysis of modern science. . . . One area to which he has devoted considerable attention is the concept of the force field in physics. The work of Michael Faraday and his successors such as Albert Einstein draws particular interest. The achievement of the field concept is that it reverses the previous view that forces are solely the unmediated result of bodies in motion, that action-at-a-distance is precluded. To Faraday, in contrast, the body is a manifestation of force field; and a force field is an independent reality prior to the body. Body and mass become secondary phenomena, concentrations of dynamic force at particular places and points in the field. Action-at-a-distance is possible.

This is theologically significant for a number of reasons. First, the problem with the post-Newtonian reduction of forces to mass in motion is that the resulting picture of the universe precludes any divine force. If God does not have a body, and if all forces require a prior body, then God cannot have force. This problem is eliminated with contemporary field theory.

This is theologically significant for a second reason. Dynamic field theories from Faraday to Einstein claim a priority for the whole over the parts. The value of this is that God and the whole are correlate categories. God, as the all-determining reality, must be conceived to be the unifying ground of the whole universe if the divine is to be conceived as creator and redeemer of the world. By appealing to the divinely granted whole of reality, Pannenberg believes he can make the effective presence of God in every single event intelligible. To increase this intelligibility, Pannenberg points out that the field concept was originally a metaphysical concept going back to the pre- Socratics. By the time the Stoics got hold of it, the field had become associated with the pneuma, the divine Spirit.

This brings us to the third reason that field theory in physics is theologically significant: it provides a possible means for conceiving of the divine Spirit as active in the natural world. Even more -- and this may be one of the most courageous of his conceptual hypotheses -- Pannenberg employs the notion of a dynamic field to describe the workings of the Spirit within the trinitarian life proper. The essence of divinity is spirit, he says; and it is due to the Holy Spirit as a dynamic force field that the Son is generated from the Father and that the two, Father and Son, are bound together in love." Ted Peters, "Introduction," in Wolfhart Pannenberg, Toward a Theology of Nature (edited by Ted Peters), (Louisville, Kentucky: Westminster Press, 1993), pp. 13-14.

Keith Ward summarizes Pannenberg's position in this way: "Wolfhart Pannenberg has suggested that one might think of the Spirit of God as such a 'total field' which environs the cosmos . . . the idea of Spirit as a 'universal field of energy' which engenders a process of creative unification, leading organism to transcend themselves towards increasingly complexity and structure. [Toward a Theology of Nature, p. 140] He appeals to the work of Teilhard in developing this view, and also to Polanyi's idea of a morphogenic field, which may be an explanatory factor individual development. The model suggests very well the way in wich God's influence would not be either intermittent or confined to some initial act of origination. It would set the origin, the limits, and the goal of the process, being a constant presence and influence at every point." Keith Ward, Religion and Creation (Oxford: Clarendon Press, 1996), pp. 298-299.

16. Metaphysics and the Idea of God (trans. by Philip Clayton), 1990, p. 30.

17. Principles of Philosophy, Part II, 37 (trans. by J. Cottingham, The Philosophical Writings of Descartes, Vol. I, p. 240).

18. "The entire conception of God's creative activity was deeply challenged in the seventeenth century because of the principle of inertia. The German philosopher Hans Blumenberg has repeatedly put his finger on this remarkable event, an event of far- reaching importance in the history of modern times. The principle of inertia as formulated by Descartes means that no longer is the continuous existence of any given state of affairs in need of explanation but only the occurrence of any changes of this status [my emphasis]. This consequence seems to be inevitable, if inertia in contrast to Descartes is understood as a force of self-preservation inherent in the body, a vis insita. On this basis, a transcendent conservation (Fremderhaltung) of nature becomes superfluous. In a similar way the mechanical interpretation of the changes occurring to the bodies in terms of a transfer of movement renders the assumption of a divine cooperation in the activities of the creatures superfluous. Thus deism must be seen as the consequence of the introduction of the principle of inertia in modern physics." Pannenberg, p. 35

19. Pannenberg, p. 31. Mortimer Adler, in How to Think About God (1980), makes essentially the same point: "In the realm of motion, the modern discovery of the principle of inertia requires us to reject as false Aristotle's view that the continuing motion of a body set in motion needs a continuing efficient cause. . . . The view held by mediaeval theologians, and some of their modern followers, concerning the continuing existence of contingent beings in the natural world, closely resembles the Aristotelian view concerning the continuing movement of a body set in motion. . . . I hold that something akin to the principle of inertia applies in the realm of existence, and leads us to reject the mediaeval view that the continuing existence of individual things needs the continuing action of an efficient cause. . . . [S]o individual things of nature, which are brought into existence by natural causes, continue in existence without the action of any efficient cause of their continuing existence; and their existence continues until the action of counteracting natural causes results in their perishing, or ceasing to be. . . . It is the natural tendency of everything that exists to persevere in existence -- by inertia, which is to say, without the action of an efficient cause that acts to cause its continuing existence." (pp. 123-125).

20. ibid., p. 20 "When, almost one hundred years after Spinoza, Immanuel Kant again used the contingency of all finite reality as a starting point for developing his idea of God, he found himself confined to the puzzlement such contingency presented to human reason; he no longer could claim a direct dependence of contingent reality on God for its preservation." [Kant, Der einzig mögliche Beweisgrund für eine Demonstration des Daseins Gottes (1763); see the commentary of H.G. Redmann, Gott und Welt: Die Schöpfungstheologie der vorkritischen Periode Kants (Göttingen: Vandenhoeck und Ruprecht, 1962), pp. 98-99, 142-148.

21. The Legitimacy of the Modern Age (1966), trans. Robert Wallace (Cambridge, MA: MIT Press, 1971), p. 137. Robert Wallace edited a special edition of Annals of Scholarship (1987) dedicated to analyses of Blumenberg's work. For a recent survey of Blumenberg's thought, see Elías José Palti, "In Memoriam: Hans Blumenberg (1920-1996). An Unended Quest," Journal of the History of Ideas 58.3 (July 1997), pp. 503-524.

22. ibid., p. 143.

23. Part II, c.3, paragraph 15. Some historians of science see a connection between the emphasis on the absolute power of God, characteristic of Nominalist thought, and the corresponding importance of divine sovereignty in the theologies of Luther and Calvin, and the development of a mechanistic conception of nature. With all causal agency located in God, it makes sense to view the world of nature as entirely passive or inert, only subject to extrinsic/external forces. Gary Deason writes: "The world as Newton described it appeared to be the product of God's action on mindless, inchoate matter. . . . Were it not for God's gracious bestowal of active forces such as gravity, the world would have languished inert and purposeless. As the key to the meaning and structure of the new mechanical world, gravity became the mark of power and grace. In the decades after Newton's Principia, theologians and religious popularizers latched onto the grace of gravity as a valuable weapon in the ongoing fight against atheism. . . . The Reformers faced a crisis in faith brought about by what they believed was a misconception of divine grace. Addressing the needs of the believer, they effected a theological revolution by focusing on the absolute sovereignty of grace and the assurance of salvation that they thought belief in it would bring. The mechanists faced the very different problem of developing a plausible conception of nature in the light of recent discoveries of mathematical laws of nature. They employed the sovereignty of God to impose laws of nature on the corpuscles of ancient atomism, making atomism into a viable worldview and laying the conceptual basis for mathematical physics. In the process, however, God changed character. The sovereign Redeemer of Luther and Calvin became the sovereign Ruler of the world machine. The Reformers' search for assurance of salvation gave way to the assurance of scientific explanation. The radical sovereignty of God between the Reformation and the Enlightenment followed the course of many concepts in the complex history of religion and science." Deason, "Reformation Theology and the Mechanistic Conception of Nature," in God and Nature: Historical Essays on the Encounter Between Christianity and Science, edited by David Lindberg and Ronald Numbers (Berkeley: The University of California Press, 1986), pp. 167-191, at pp. 185, 187. Michael Buckley, in At the Origins of Modern Atheism (Yale, 1987), argues that the attempt to use science as a justification for belief -- especially evident in the seventeenth century -- paves the way for modern atheism.

24. Pannenberg, p. 35.

25. It is important to note that those who speak of such a "settlement" also argue that contemporary science, especially relativity theory and quantum mechanics, have altered this settlement so radically that theologians and philosophers must adjust their understanding of nature, human nature, and God to take into consideration the new scientific perspective(s).

26. For those who dislike the notion of "truth" and "falsity" in discussions of claims about the world, the argument is simply that the new paradigm has replaced an old one.

27. One could, of course, discuss the denial of final causality in nature or the reduction of qualities to quantity, but these are more specifically developments in natural philosophy. It is the principle of inertia which is the key doctrine to examine.

28. Principia, Definition VIII, trans. by Florian Cajori (University of California Press, 1971), pp. 4-5.

29. Principia, pp. 5-6.

30. Principia, Book III, p. 397.

31. Principia, p. 550.

32. Principia, p. 11.

33. I am indebted to the work of William Wallace for these insights about the character of the principle of inertia. See note 36, below.

34. There is no explicit discussion in the Principia about the need for an extrinsic cause for motion, apart from what Newton says about God as universal mover. Nevertheless, in some reflections on mechanics at the end of the Optics, Newton observes: "The vis inertiae is a passive principle by which bodies persist in their motion or rest, receive motion in proportion to the force impressing it, and resist as much as they are resisted. By this principle alone there never could be any motion in the world. Some other principle was necessary for putting bodies in motion; and now they are in motion, some other principle is necessary for conserving motion." Opticks III. 1 4th edition (1750) (New York: Dover, 1952) p. 397.

35. We must remember that "quantity" can be studied 1) in metaphysics as a category of being; 2) in physics as a property of substance (and according to its [quantity's] proper nature; and 3) in mathematics as it has certain properties that lack any order to substance -- hence as "nude quantity."

36. William Wallace's early work on the principle of inertia, upon which my analysis depends, is "Newtonian Antinomies Against the Prima Via," The Thomist XIX.1 (April 1956), pp. 151-192. See also, James Weisheipl, "Galileo and the Principle of Inertia," in Nature and Motion in the Middle Ages, edited by William E. Carroll (Washington, D.C.: The Catholic University of America Press, 1985), pp. 49-73.

37. Many historians of science in this century have concentrated on the role of mathematics in the Scientific Revolution. E. A. Burtt and Alexandre Koyré, for example, accepted the central importance of the principle of inertia in identifying the revolutionary character of seventeenth century science, but they located the development and the enunciation of the principle in the context of a mathematization of nature. In what has become a classic text, The Metaphysical Foundations of Modern Science, E. A. Burtt summarizes this position: "We have observed that the heart of the new scientific metaphysics is to be found in the ascription of ultimate reality and causal efficacy to the world of mathematics, which world is identified with the realm of material bodies moving in space and time. Expressed more fully . . ., the real world in which man lives is no longer regarded as a world of substances possessed of as many ultimate qualities as can be experienced in them, but has become a world of atoms (now electrons), equipped with none but mathematical characteristics, and moving according to laws fully statable in mathematical form." E.A. Burtt, The Metaphysical Foundations of Modern Science (1952) (Atlantic Heights: N.J., 1980), p. 303. In what is perhaps his most famous book, From the Closed World to the Infinite Universe, Alexandre Koyré argues that the Scientific Revolution is, at its core, a fundamental metaphysical shift away from a finite Aristotelian universe of qualitative distinctions to a universe of infinite geometrical space in which physical reality is exhaustively captured in mathematical terms. Newton's principle of inertia is, for Koyré, inconceivable without this change in metaphysics. Only in an infinite universe could one conceive of uniform motion in a straight line forever.

Whether it be Thomas Aquinas in the thirteenth century or Galileo in the seventeenth, no major thinker in the Middle Ages or the Renaissance was unaware of the importance of understanding the connections uniting and the differences separating mathematics and the natural sciences.

38. Natural bodies are not constituted, are not made what they are, by their quantitative dimensions; and, thus, mathematical measures are not the principles of explanation in physics: since the principles of explanation in physics must provide the explanation for what constitutes the body as such. To explain the nature of a tree or a molecule requires knowing what makes a tree be a tree, or a molecule be a molecule. The science of nature, in all its branches, is an autonomous science having its own proper principles, and is, thus, distinct from and not dependent upon mathematics. In the Aristotelian tradition, although mathematics and physics are both theoretical sciences they differ in what they study. Physics -- again, what we would call the natural sciences, or perhaps what we should call a broad, general science of nature which includes all the natural sciences -- [physics] studies the world of matter-in-motion [ens mobile]: what is perceptible; what we can see, or smell, or taste, or touch, or hear; the world of concrete physical reality as it undergoes generation and destruction, changes of place, shape, and the like. Mathematics, on the other hand, has as its object the quantitative features of the world of physical reality -- those quantitative dimensions which exist in physical objects but which can be considered separate from them. The geometer, for example, studies spheres, not spherical basketballs. They think that the human mind has the ability to separate intellectually geometric forms from physical matter and to know these forms in their separated state, but the sphere which a geometer studies does not truly exist prior to a spherical body. For Albert and Thomas, the mathematician studies quantities which, although necessarily existing in sensible matter, can be understood without such sensible matter. Many of the advances in science since the time of Aristotle -- Euclid's systematization of geometry, Archimedes' discoveries in mechanics, the astronomy of Ptolemy, and advances in optics -- lent support to the Platonic view that mathematics affords the only truly scientific explanation of natural phenomena. Yet, in the middle of the thirteenth century, Albert the Great in his commentary (paraphrase) on Aristotle's Metaphysics attacked: "the error of Plato, who said that natural things are founded on mathematical [things], and mathematical being [is] founded on divine [being], just as the third cause is dependent on the second, and the second on the first; and so [Plato] said that the principles of natural being are mathematical, which is completely false." [Lib. I Metaph. tr. 1, c. 1 [Borgnet 6, p. 2b]] The "error of Plato," according to Albert, is not simply an illegitimate emphasis upon the importance of mathematics, but is, rather, a defective understanding of metaphysics and epistemology. [In his commentary on the pseudo-Aristotelian Liber de causis, Albert lists for main errors of the Platonists: 1) they allow for motions without the contact of some efficient cause; 2) they identify principles of knowing with principles of being, so that once they have postulated an exemplar they think they have explained the cause of the thing; 3) they postulate subsistent numbers as the per se principles of physical things; 4) they make solids, surfaces, and lines flow from a point to constitute a corpus mathematicum, to which they add a corpus naturale, as though it were an additional forma. [Liber de causis I, tr. 1, c. 4 (Borgnet 10, 368b-369a)]] Albert, following Aristotle, affirms that the proper principles of the natural sciences are not mathematical. The natural sciences (i.e., physics) are not subordinate to an allegedly "higher" science of mathematics. "Dimensions are not principles of bodies according to any esse [any thing which makes the body what it is], rather they [dimensions] are consequent upon the fact that they [bodies] are concrete physical bodies having proper principles like matter and form, and that the form giving the existence is in this matter." [Lib. I Metaph. tr. 1, c. 1, [Borgnet 6, pp. 2b-3a]]

39. Aquinas' most important work in this respect can be found in his Commentary on Boethius' 'On the Trinity' (questions 4 and 5) and in his commentary on the second book of Aristotle's Physics.

40. Aquinas locates the fundamental error of the Platonists in their failure to understand the way in which the intellect functions in the acquisition of knowledge. Because the intellect is able to consider a nature, or an essence, or a quantitative dimension without thinking of the respective individuals whose nature it is, Platonists think that the nature or essence or quantitative dimension must truly exist separate from the individuals. Platonists confuse the order of intelligibility and the order of existence. Simply because the object of thought -- a triangle, or a square, or a sphere -- is, in itself, intelligible, Platonists conclude that such an object of thought must have a substantial existence. Here is how Albert the Great puts it: "This [in my judgment] has been the entire cause of the controversy between Plato and Aristotle, that he [Plato] wished to utilize arguments of a logical order, and deduced from them principles of the real world. Aristotle, however, does not do this, but looks for principles of real things from within the natures of thins." [In II Sent. 1, a. 4, ad 4 (Borgnet 27, 15a)]

41. The importance of mathematics in the thought of Galileo and Newton led, has led some scholars such as E. A. Burtt and Alexandre Koyré, to see the Scientific Revolution as a radical shift in metaphysics: a return, if you will, to the heritage of Plato and a rejection of Aristotle. Such an interpretation misses an important point in the mediaeval understanding of the relationship between mathematics and physics.

42. Commentary on Boethius' 'On the Trinity' q. 5, a. 3, ad 5 [The Division and Methods of the Sciences, translated by Armand Maurer (Pontifical Institute of Mediaeval Studies, 1963), p. 36. See also, In II Phys. lec. 3, n. 8. "So there are three levels of sciences concerning natural and mathematical entities. Some are purely natural and treat of the properties of natural things as such, like physics . . . . Others are purely mathematical and treat of quantities absolutely, as geometry considers magnitude and arithmetic number. Still others are intermediate, and these apply mathematical principles to natural things; for instance, music, astronomy, and the like. These sciences, however, have a closer affinity to mathematics, because in their thinking that which is physical is, as it were, material, whereas that which is mathematical is, as it were, formal. For example, music considers sounds, not inasmuch as they are sounds, but inasmuch as they are proportionable according to numbers; and the same holds in other sciences. Thus they demonstrate their conclusions concerning natural things, but by means of mathematics." (Maurer, pp. 37-38) For an insightful discussion of this treatise, see Stephen L. Brock, "Autonomia e gerarchia delle scienze in Tommaso d'Aquino. La difficoltà dellla sapienza," in Unità e autonomia del sapere. Il dibattito del XIII secolo, ed. Rafael Martínez , pp. 71-96 (Roma: Armando Editore, 1994).

43. And here, of course, I am following in the footsteps of James Weisheipl, William Wallace, and others.

44. One of the great achievements of Albert the Great and Thomas Aquinas was their clear demonstration of the autonomy of the natural sciences: an autonomy, by the way, with respect to theology and to faith, as well as with respect to mathematics. They had no doubt that the physical universe is intelligible and that it is, therefore, an appropriate object of scientific investigation. The natural scientist explains change in its many forms: generation and destruction, locomotion, alteration, and the like. A science of generation and destruction, locomotion, and alteration must provide explanations in terms of the proper causes for these changes. The principles used in these explanations are not mathematical. And it does not matter whether we are speaking of productive, practical, or theoretical science. How can points, lines, surfaces, numbers, or equations -- principles of mathematics -- how can these cause the construction of houses or the writing of a poem? How can points, lines, surfaces, numbers or equations cause men to fashion constitutions, to engage in commerce or to live virtuously? How can points, lines, surfaces, numbers or equations cause the birth of an animal, the growth of an acorn into an oak tree, the movement of either planets or subatomic particles? As Albert and Thomas clearly understood, scientific explanations -- explanations in terms of causes -- employ the principles appropriate to each science. Although mathematics is clearer and more certain than the natural sciences, we must resist the temptation to regard mathematics either as the only true science or as a substitute for the natural sciences.

45. Rocks of Ages, p. 193.

46. Much work needs to be done by those in the Thomistic tradition to incorporate the discoveries of modern science into a broader philosophy of nature. Three authors who have worked in this area are: Benedict Ashley, Theologies of the Body; Richard Connell, Substance and Modern Science; and William Wallace, From a Realist Point of View and The Modeling of Nature.