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Loyola Marymount University From the SelectedWorks of Timothy Shanahan September, 1989 "Kant, Naturphilosophie, and Oersted's Discovery of Electromagnetism: A Reassessment" Timothy Shanahan, Loyola Marymount University Available at: http://works.bepress.com/timothy_shanahan/6/ TIMOTHY DISCOVERY SHANAHAN* AND OERSTED’S OF ELECTROMAGNETISM: A REASSESSMENT DANISH chemist and physicist Hans Christian Oersted (1777-I 851) is recognized by historians of science primarily as the discoverer of electromagnetism. His experiments in 1820 demonstrated a definite lawlike relationship between electrical and magnetic phenomena. The quite general question of whether there is in science such a thing as a “logic of discovery” can in this case be given a more precise formulation. Why was Oersted, rather than another of the many scientists interested in electricity and magnetism in the nineteenth century, the fortunate one to have made the discovery, and thus to have his name immortalized in the history of science? What events, ideas, or methods were responsible for the discovery? A number of possibilities might occur to the historian. Perhaps it was merely a matter of time. Sooner or later someone had to discover electromagnetism. If it had not been Oersted, then it would have been someone else. The fact that it was Oersted, and not someone else, may simply reflect nothing more than his THE good luck. In fact, the dominant view of Oersted’s discovery for most of this century held that it was simply a matter of chance that Oersted stumbled upon the phenomenon. For example, an issue of the Open Court for 1913 carried an article by Philip E. B. Jourdain entitled “An Accident that Led to a Notable Discovery”. Jourdain remarked that, “In Ernst Mach’s well-known lecture ‘On the Part Played by Accident in Invention and Discovery’, there is no mention of the remarkable accident that led to Oersted’s momentous discovery of the action of an electric curent on a magnetic needle.“’ Jourdain then proceeds to quote a long excerpt from a letter of Christopher Hansteen, an associate of Oersted’s, to Faraday, dated 30 December 1857. In the letter Hansteen describes Oersted as “a man of genius”, but also as “a very unhappy experimenter” who could not manipulate instruments. After a lecture, he says, Oersted happened to place a wire connected to a battery parallel to a magnetic needle, and was “quite struck with perplexity” to see that the movement of the needle corresponded to the direction of the current in the wire. The letter, *Department of Philosophy, Loyola Marymount University, Los Angeles, CA 90045. U.S.A. Received 19 Much 1986; in revisedform 30 July 1988. ‘P. E. B. Jourdain, ‘An Accident that Led to a Notable Discovery’, Open Court 27 (1913), 3940. Ernst Mach, ‘On the Part Played by Accident in Invention and Discovery’, Popular Scientific Lectures, 3rd edn (Chicago, 1898). pp. 259-281. Stud. Hist. Phil. Sci., Vol. 20, No. 3, pp. 287-305, Printed in Great Britain 287 1989. $3.00 + 0.00 0039-3681/89 Q 1989. Pergamon Press pk. Studies in Histwy 288 which purports to recount the “accident” leading with the remark that, “Thus the great discovery und Philosophy of Science to the discovery, culminates was made; and it has been said, not without reason, that ‘he tumbled over it by accident’.“’ The idea that Oersted’s discovery in 1820 of electromagnetism was simply an accident seems to have been the “received view”, even among historians, for about a century after the announcement of the discovery. It was then that scholars such as Meyer’ and Stauffer4 demonstrated that Oersted’s discovery was anything but accidental, because he had by that time been working on the very problem of the relationship between electricity and magnetism for many years. (Meyer has shown, ironically given Hansteen’s claims, that Oersted was in fact a gifted experimenter, and that it was Hansteen who was rather clumsy in the laboratory.) As a result of such historical studies, the popularity of the “accident” account has diminished. Now, however, the pendulum seems to have swung in the other direction. Far from it being merely a “chance” event or an accident. Oersted’s discovery is now seen as having a very specific, but initially somewhat surprising, causal source. It is currently popular to claim that Oersted’s discovery was the direct result of his allegiance to ~uturp;nhilosonot phie. So, for example, Stauffer declares that, “It was Natu~philosol~hit, chance, that led to the discovery of electromagnetism”.5 L. Pearce Williams, after describing Oersted’s discovery, expresses much the same view: Thus it was that nature philosophy led Oersted to a discovery which has immortalized his name in the history of science. It should be insisted upon that it was nature philosophy that was responsible for the discovery. There can be no doubt of the importance of Oersted’s discovery, nor of its relation to nature philosophy as a whole. Certainly the assumptions of this school of thought seemed, finally. to have been justified by the new discovery.h According to this view, Nuturphilosophie, despite all its philosophical excesses, ought to be credited with leading to Oersted’s discovery of electromagnetism. This is an interesting claim, both historically and philosophically, because if true, then far from being the scientifically barren philosophical movement it is :H. Bcnce Jones, 7he Ll/> a&Lrrrers afFaradaq>(London, 1870), Vol. II, pp. 3955397. Jourdain (op. cir., note I, p. 40) substitutes the word ‘discovery’ where the original has ‘detection‘. ‘K. Meyer, ‘The scientitic life and works of H. C. Oersted’, in: Oersted’s Natrrrvidensh-crhelj~~ Skr$tcr S&nt[fic Papers, K. Meyer (ed.). 3 Vols (Copenhagen, 1920). Vol. I, pp. xviii-clxvi, and ‘Faraday and Oersted’, Nature 128 (193 I), 337-339. “R. C. Stauffer, ‘Persistent Errors Regarding Oersted’s Discovery of Electromagnetism’, Isis 44 (1953). 3077310, and Speculation and Experiment in the Background of Oersted’s Discovery of Electromagnetism’, Isis 48 (1957), 33350. ‘Stauffer (1953). p. 310: cf. his (1957). pp. 33, 35, 48, 50, for similar claims. ‘L. Pearce Williams. The Origins o/‘Firld Thror~ (Clinton, Mass: Random House, 1966). pp. 59~ 60. Williams places the greatest stress on the clajm that Oersted’s discovery of electromagnetism should be attributed to his devotion to Natu~/~/ti/uso/,hir, even identifying Oersted hrmself as a Natwphilowph (p. 52). Similar claims are made in his ‘Kant, Naturphilosupllie, and scientific method’. in: Foumlrrtirm of‘ Sc~imtiji<~Method: Ihc Nitwtwttth Cwmq, R. N. Giere and R. S. Westfall (eds) (Bloomington, Indiana: Indiana University Press. 1973). p. X. Oersted’s Discovery of Electromagnetism often portrayed the advancement as, Naturphilosophie of natural treat Naturphilosophie science. as a somewhat 289 has actually Standard curious been an important histories force for of philosophy (if not embarrassing) which episode in nineteenth-century German philosophy, which enjoyed popularity for a time before passing into oblivion and leaving no enduring contributions to knowledge, will have to be rewritten. Naturphilosophie will have to be given its due, and accorded the respect it deserves as the cradle of one of the most important discoveries in the history of science. The tendency to react, and perhaps overreact, to the view that Oersted’s discovery was accidental, by fixing on Naturphilosophie as the cause, is understandable. Indeed, any account of his discovery which omits to mention the role of Naturphilosophie will provide at best an incomplete picture of this episode in science. Nonetheless, it is misleading to attribute to this source the preeminence Stauffer and Williams do in the above quotations. The time is ripe for a reassessment of the roots of Oersted’s discovery. Whereas others have argued that it was Oersted’s devotion to Naturphilosophie that resulted in his discovery, I shall argue that it was his deeply rooted acceptance of certain Kantian docrines, and his explicit rejection of central doctrines of Naturphilosophie, that made his discovery possible. Thus, direct and indirect evidence suggests that Naturphilosophie played a far different, and less important, role in Oersted’s discovery than is now commonly supposed. If there is a philosophical stimulus behind this event then it must be identified as Kant. In the sections which follow I distinguish between Kant’s doctrines and those characteristic of Naturphilosophie, and show how Oersted’s early interest in Kant continued to inform his experimental work and his theoretical explanations of physical phenomena, culminating in his discovery of electromagnetism. If this paper stimulates historians and philosophers of science to think again about the cogency of the present “received view” of Oersted’s discovery, and to pursue the suggestions in the present paper in greater detail than I am able to do here, it will have served its purpose. 1. The Seminal Influence of Kant Oersted’s early devotion to Kantian ideas can be said, without exaggeration. to have influenced the entire subsequent course of his scientific and philosophical interests. Kant’s philosophy was an established part of the curriculum in natural philosophy at the University of Copenhagen where Oersted studied between 1793 and 1799 (taking a doctorate in pharmaceutical science). In 1798 he served as a member of the editorial board of Philosophisk repertorium for faedrelandets nyeste litteratur, a new journal established as a platform for expounding the Critical Philosophy. In 1799 he published a work entitled Grundtraekkene af Naturmetaphgsiken rildeels efter en n)le Plar; (Fundamental 290 Studies in History and Philosophy of’ Science Features of Metaphysics, partly on a New Plan).’ His interest in Kant found further expression in his doctoral dissertation of the same year entitled “Dissertatio works drew de forma metaphysices elementaris heavily on Kant’s Kritik der reinen Reason) and Metaphysische cal Foundations ?f Natural naturae Vernmft externae”.’ These (Critique sf Pure Arzfangsgriinde der Naturwissenschaft (MetaphysiScience).’ Because Kant’s thought in these works played such an important role in the formation of Oersted’s philosophica orientation, the relevant doctrines will be discussed at some length. This will provide the background for claims to be made later concerning the factors contributing to Oersted’s discovery of electromagnetism. In an appendix to the Transcendental Dialectic in the Kritik, Kant included a section entitled “The Regulative Employment of the Ideas of Pure Reason”.” One of the main points Kant emphasizes here is that concepts have valid application only within the realm of possible experience. When one attempts to employ concepts beyond the field of possible experience, one is inevitably led into all kinds of deception and error. Transcendental ideas, Kant says, never allow of any constitutive employment. But they do serve a legitimate, and indeed indispensable, regulative function, namely, “that of directing the understanding towards a certain goal upon which the routes marked out by all its rules converge, as upon their point of intersection”.” He goes on to say that a distinctive feature of reason is that it strives for systematization, i.e. to exhibit the connection between items of knowledge with respect to a single principle. This idea of the whole as a system connected by necessary laws is always presupposed in the knowledge of each item. “These concepts of reason are not derived from nature; on the contrary, we interrogate nature in accordance with these ideas, and consider our knowledge as defective so long as it is not adequate to them”.” He adds that, “This unity aids us in discovering a principle for the understanding in its manifold (manni&altigen) and special modes of employment, directing its attention to cases which are not given. and thus rendering it more coherent (zusammenhiingend).” Kant illustrates these ideas with respect to ‘power’ or ‘force’ (Kraft). Earlier ‘Reprinted in Oersted’s Naturvidenskabelige Skrifer, Vol. I, pp. 33-78. ‘Skrifier I, pp. 79-105. Published in German translation as Ideen zu einer neuen Architektonik der Naturmetaphysik (Berlin, 1802). ‘For this paper 1 have used Norman Kemp Smith (trans.), Immanuel Kant’s Critique qf Pure Reason (New York: 1929), and James Ellington (trans.), Metaphysical Foundations of Natural Science (Indianapolis: Bobbs-Merrill, 1970). All references to the Anfungsgriinde are to this translation. This has recently been reissued as Emmanuel Kant: Philosophy of Materiul Nature (Indianapolis: Hackett, 1985). “‘Critique A 643/B671pA669/B697; “A” and “B” refer to the first and second editions of the Critique, respectively. “Critique A6441B672. “Critique A646/B6?4. “Critique A647iB675. 291 Oersted’s Discovery of Electromagnetism in the Kritik he argued concept of substance against is nothing an atomistic view of nature, other than our concept proposing that our offorce. We are acquainted with substance in space only through forces which are active in this and that space, either bringing other objects to it (attraction), or preventing them penetrating into it (repulsion and impenetrability). We are not acquainted with any other properties constituting the concept of the substance which appears in space and which we call matter.14 Kant’s point here is an epistemological one. It concerns what we can and know or conceive of with respect to material substance. This view had important implications for natural science. It is worth quoting Kant at length. cannot The various appearances of one and the same substance show at first sight so great a diversity, that at the start we have to assume just as many powers as there are different effects. Now there is a logical maxim which requires that we should reduce, so far as may be possible, this seeming diversity, by comparing these with one another and detecting their hidden identity. Though logic is not capable of deciding whether afundamental power actually exists, the idea of such a power is the problem involved in a systematic representation of the multiplicity of powers. The logical principle of reason calls upon us to bring about such unity as completely as possible; and the more the appearances of this and that power are found to be identical with one another, the more probable it becomes that they are simply manifestations of one and the same power, which may be entitled, relatively to the more specific powers, the fundamental power. He adds that, “The relatively fundamental powers must in turn be compared with one another, with a view to discovering their harmony, and so to bring them nearer to a single radica!, that is, absolutely fundamental, power.15 Finally, “We must endeavour, whenever possible, to bring in this way systematic unity into our knowledge”.” In short, Kant argues that the regulative use of the idea of a unity of fundamental forces provides the foundation for a systematic inliestigation the practice of natural griinde. of nature. This view had important consequences for science, which Kant develops further in the Anfangs- The Metaphysische Anfangsgriinde der Naturwissenschqft (1786) was published between the first (178 1) and second (1787) editions of the Kritik, and as one would expect, the two works are complementary in important respects. In the Kritik Kant focuses on the general conditions for the possibility of knowledge, wherever knowledge claims are at issue. In the Anfungsgriinde he is more narrrowly concerned with the conditions for the possibility of knowledge in natural science, especially in physics. In particular, this work adds the empirical assumption of matter, i.e. real moving stuff. To Kant this required ‘“CririqueA256/B321. “Critique A649/B617. “Critique A650/B678 Studies in History and Philosophy of‘ Science 292 an explication of the general a priori principles of the systematic understanding of (the empirical notions of) matter and motion. Again, this requires metaphysics According with respect to the explication of physical phenomena. The mechanical explicates all the varieties of matter by the combination philosophy absolutely a of corporeal nature in terms of attractive and repulsive forces. to Kant, there are only two ways of proceeding in natural science full with the absolutely empty, i.e. atoms natural of the and the void.” Its essentials consist in the assumption of the absolute impenetrability of the primitive matter, in the absolute homogeniety of the primitive matter, differences only being allowed in the shape, and in the absolute unconquerability of the cohesion of the matter in these fundamental particles themselves.lx Natural phenomena are explained as arising from the shape of these primary parts as machines set moving by some externally impressed force. The mechanical mode of explication assumes “empty intermediate spaces and fundamental particles of determinate shapes, neither of which can be discovered and determined by an experiment”.” Kant’s primary objection to the mechanical mode of explication is that it leaves far too much liberty to the investigator to construct explications of natural phenomena in an adhoc manner. Everything that relieves us of the necessity of having recourse to empty spaces is an actual gain for natural science. For these give far too much freedom to the imagination to supply by fiction the lack of intrinsic knowledge of nature. Absolute emptiness and absolute density are in the doctrine of nature approximately what blind chance and blind fate are in metaphysical science, namely, a barrier for the investigating reason or else reason is lulled to sleep on the pillow of occult qualities.‘O Besides the mechanical physical phenomena tion and repulsion. way there is the dynamical through the combination way, which explicates of the original all forces of attrac- [T]hat mode of explication which derives the specific variety of matter not from matters as machines, i.e., as mere tools of external moving forces, but from the proper moving forces of attraction and repulsion originally belonging to those matters may be called the dynamical natural philosophy.2’ On this view “matter does not (as the merely fill its space by absolute mechanical impenetrability, but by repulsive its degree, which can be different in different matters”.22 ‘7Anfangsgriinde, p. 9 1. ‘“At-$angsgriinde. p. 9 1. “Anfangsgriinde, p. 92. ‘“Anfang.vgriinde, p. 90. 2’Anfangsgrlnde. p. 9 1. *‘Anfangsgriinde, p. 92. Note the preparation section in the Critique c$Pure Reason. investigators assume) force; this force has of this idea in the “Anticipations of Perception” 293 Oersted’s Discovery of Electromagnetism Matter and the motions the fundamental apriori. different forces it undergoes of attraction are, according and repulsion. to Kant, This a product much of is certain But we do not know apriori the specific form such forces take in circumstances. This is why empirical physics is necessary. In order to account for the specific behavior of matter in motion, to appeal to the particular forces known only through out, quite correctly, that mere perception of bodies in constitute physics as a science. Perceptions without there is no recourse but experience. Kant points motion is insufficient to systematization remain merely a collection of facts, lacking coherence. For physics to become a science it must reduce the multiplicity of forces provided by empirical observation to a rational unity. 23What is needed is a formal schematism of matter’s constitutive forces, as experience reveals them to us, which will serve as a preliminary to physics by reordering the empirical search for forces in their concrete realization. This formal schematism will point out in an apriori manner how the formal conditions of cognition serve as a directive for the discovery of all the empirical forces that physics searches for.24 This schematism is sketched out by Kant in the Anfangsgriinde, especially in the second chapter entitled, “Metaphysical Foundations of Dynamics”. Dynamics is described as the science of matter in motion. “The universal principle of the dynamics of material nature is this: all that is real in the objects of our experience and is not merely a determination of space (place, extension, and figure) must be regarded as moving force”.25 In this way, Kant says, absolute impenetrability (as imagined by atomists) is banished from natural science as an empty concept, and is replaced by repulsive force. Attractive force is also posited as “a fundamental force necessary even to the possibility of the concept of matter”.26 If we thought of bodies as possessing only a repulsive force, then all bodies would be infinitely distant from one another. If we thought of bodies as possessing only an attractive force, then the whole universe would collapse 13For further discussion, see Ellington’s essay, “The Unity of Kant’s Thought in His Philosophy of Corporeal Nature”, directly following his translation of Kant’s Anf~ngsgriinde (op. cit., note 9). especially p. 216. Kant’s philosophy of science has been the subject of considerable interest in recent years. Especially useful discussions (in English) may be found in G. Buchdahl, Meraphysics and the Philosophy of Science (Oxford: Basil Blackwell, 1969). G. G. Brittan, Jr., Kantk Theory qf Science (Princeton, N.J.: Princeton University Press, 1978), R. E. Butts, Kunt and the Double Government Methodology. Supersensibility and Method in Kant% Philosophy of Science (Dordrecht: D. Reidel, 1984), R. E. Butts (ed.), Kunf’s Philosophy of Physical Science (Dordrecht: D. Reidel, 1986). For the purposes of this paper I have foregone a more detailed exposition of Kant’s views which takes into account all the technical issues presently the subject of debate, in favor of a formulation of his views which reflects the form of his doctrines Oersted would have been familiar with. Readers interested in a deeper understanding of Kant’s views should consult the abovementioned works. (Similar remarks pertain to my treatment of Schelling’s doctrine in this paper.) 24For a good discussion of Kant’s later assessment of his success in this endeavor, see G. DiGiovanni, ‘Kant’s Metaphysics of Nature and Schelling’s Ideas fbr a Philosophy of Nature’, Journal qfrhe Hist0r.v of Philosophy 17 (1979), 197-215. 2SAnfangsgriinde, p. 77. ‘bAnfangsgriinde, p. 77. 294 Studies in History and Philosophy of Science into a mathematical point of infinite density. A body on this view can be understood as consisting of an equilibrium between the opposing forces of attraction and repulsion. tal to our understanding ways in sense perception. These two basic forces (GrundkrLifte) are fundamenof matter as it manifests itself in “infinitely diverse” The task for physics is to explain other forces and physical phenomena in terms of these fundamental forces. “[A]11 natural philosophy consists in the reduction of given forces apparently diverse to a smaller number of forces and powers sufficient for the explication of the former”.” This approach promises to “enlarge the field of the investigator of nature” by removing the limitations previously imposed on natural science by a conception of nature as consisting of atoms and empty space. This conception is thus “more favorable to experimental philosophy inasmuch as it leads directly to the discovery of the moving forces proper to matter and the laws of such forces”.28 Despite its great potential for experimental research, there are also dangers in this approach that Kant is careful to warn against. “But one must guard against going beyond what makes the universal concept of matter in general possible and wanting to explain apriori the particular or even specific determination and variety of nature”.2y This is because, “no law whatever of attractive or of repulsive force may be risked on apriori conjectures; but everything, even universal attraction as the cause of gravity, must, together with the laws of such attraction, be concluded from the data of experience”.3” If this is true of physics, it is a fortiori true of chemistry, which was still the subject of considerable controversy. “Still less will such conclusions in regard to chemical affinities be permitted to be tried otherwise than by means of experiment. For to comprehend original forces apriori according to their possibility lies generally beyond the horizon of our reason”.3’ Kant concludes that, “the investigation of metaphysics behind what lies at the basis of the empirical concept of matter is useful only for the purpose of leading natural philosophy as far as possible in the investigation of the dynamical grounds of explication, because these alone admit the hope of determinate laws, and consequently of a true rational coherence of explications”.” Kant’s cautions about the proper limits of metaphysical theorizing with regard to natural science were often ignored by those who read him. This was true of the philosophers associated with Naturphilosophie. 2’Anfangsgriinde, 2”Anfangsgriinde, 2qAnfangsgriinde, “‘A~fangsgriinde, “Anfangsgrtinde, ‘2Anfangsgriinde, p. p. p. p. p. p. 93. 92. 78. 93. 93. 93. Oersted and Naturphilosophie Nuturphilosophie can be looked at, not so much as a “school” with well- defined doctrines, but rather as a loosely connected set of ideas and beliefs which found their fullest expression in the early writings of Friedrich Wilhelm Joseph von Schelling (I 775-I 854). Schelling’s philosophy has recently been given careful and detailed treatment by Esposito. He writes that common to most thinkers who would describe themselves as Naturphilosophen was a commitment “to seek interrelations among natural phenomena and to eventually bring about a unity of nature and culture”.” Nuturphilosophie sprung from seeds planted by Kant’s Kritik and Anfangsgriinde. “These two works, together with Jacobi’s Spinoza work, present the key ideas that would serve as the point of departure for Schelling’s own approach to the concept of matter, so that there can be no doubt of Schelling’s indebtedness to Kant here, as with later arguments as we11”.j4 The Kantian foundation for Schelling’s philosophy is clearly discerned in his writings on the metaphysics of nature. In his Ideen zu einer Philosophie der Natur (1797) he tried to show that nature is animated by opposing forces, fundamental dualities, and polarities. This thesis recurs in many of his early writings3’ His interest in the physical polarity of dual forces of nature is, of course, a development of Kant’s doctrine of the Grundkrbpe, the basic forces of attraction and repulsion. Instead of physical phenomena being constituted of opposing forces in stable equilibrium with one another, such phenomena are seen as the manifestation of one or another aspect of force, all of which aspects are present in each phenomenon to some degree. Nature is thus seen as an integrated and interconnected organic whole - as a system. If this is so, he reasoned, then it should be possible to connect diverse physical phenomena within a unified theoretical physics. Such unification would be achieved on the basis of a metaphysics of nature, developed along broadly Kantian lines. Although Schelling was strongly influenced by Kant, he came to the conclusion that Kant was fundamentally mistaken in some crucial respects. First, he criticized Kant for presenting a reductionistic view of nature which “J. L. Esposito, ScheNing’s Idealism and Philosophy of Nature (Cranbury, N.J.: Associated University Press, 1977), p. 137. 34Esposito, op. cif., note 33, p. 49. Another important source for Nulurphilosophie, which I will not discuss in this paper, is Kant’s Critique of Judgement (1790). “See especially the following works [volume and page references refer to Schelling’s Siimmtliche Werke, K. F. A. Schelling (ed.) (Stuttgart and Augsburg, 185&1861)]: ‘Ideen zu einer Philosophie der Natur’ (1797; 2: l-343), ‘Von der Weltseele, eine Hypothese der hiiheren Physik zur Erkliirung des allgemeinen Organismus’ (1798; 2: 345-584), ‘Erster Entwurf eines Systems der Naturphi!?sophie’ (1799; 3: l-268), ‘Einleitung zu dem Entwurf eines Systems der Naturphilosophie, oder Uber den Begriff der speculative Physik und die innere Organisation eines Systemes dieser Wissenschaft’ (1799; 3: 269-326), ‘Allgemeine Deduktion des dynamischen Processes, oder der Kategorien der Physik’ (1800; 4: l-78), ‘Darstellung meines Systems der Philosophic’ (1801; 4: 105-212). 296 Studies in History and Philosophy fails to recognize zu dem Entwurf the higher principles eines Systems of natural phenomena. der Naturphilosophie qf Science In the Einleitung (1799), he wrote: [T]he notions of dynamical physics hitherto diffused, are very different from, and partially at variance with, those which the author lays down.. I speak of the modes of representations which have been put into philosophic heads by Kant, and which may be mainly reduced to this: that we see in matter nothing but the occupation of space in definite degrees, in all of matter, therefore, only mere difference of occupation of space (i.e. density), in all dynamic (qualitative) changes, only mere changes in the relation of the repelling and attracting forces. The problem the “higher” with such a view, according to Schelling, is that it utterly principles standing behind natural phenomena. ignores Now, according to this mode of representation, all the phenomena of Nature are looked at only on their lowest plane, and the dynamical physics of these philosophers begin precisely at the point where they ought properly to leave off. Even magnetic and electric phenomena, he says, when viewed from this standpoint, will be seen as a product of the fundamental forces. Schelling’s opposition to this approach is unequivocal. “lw]e are convinced that this so-called dynamical principle is too superficial and defective a basis of explanation for all Nature’s phenomena, to reach the real depth and manifoldness of natural phenomena”.‘6 According to Esposito, “In Schelling’s view Kant had not gone far enough in drawing out the implications of the dynamic conception of matter”. In his Abhandlungen zur Erliiuterung des Idealismus der Wisssenschaftslehre,” Schelling, like Kant, had characterized matter as an equilibrium of opposing forces. “Where he departs from Kant, however, is over the interpretation of what the analysis of matter actually reveals to US”.~* Because Schelling believed that Kant had already shown that “matter is matter only insofar as it is an object of intention or action”, he concluded that nothing actually remained of the object apart from spiritual activity. According to Schelling, what we call matter is really “spirit intuiting its activities in equilibrium”.39 The attractive and repulsive forces of which Kant spoke are for Schelling really dimensions of spiritual reality itself. Such forces are, on Schelling’s view, inconceivable as existing outside the realm of spirit.40 Schelling departed from Kant in a second way. Unlike Kant, Schelling held that the laws of nature could be infallibly inferred from reason. Because jb‘On the Possibility of Speculative Physics’, in his: ‘Introduction to the Outline of a System of Natural Philosophy’, Tom Davidson (trans.), Journal of Speculative Philosophy 1 (1867), 198; see also 205. “Siimmtliche Werke, op. cit., note 35, 1: 343-452. ‘*Esposito, op. cit., note 33, p. 54. ‘9Siimmtliche Werke, op. cit., note 35, 1: 380; quoted in Esposito op. cit., note 33, p. 55. %ee Esposito, op. cit., note 33, p. 55. Oersted’s Discovery qf Electromagnetism Denken govern 291 and Sein are equivalent, the same laws that govern the physical world as well. If nature truly constitutes can expect a deduction from abstract possible. quotation The following principles to concrete the spiritual world a system, then we phenomena gives a good sense of Schelling’s to be view. The assertion is, that all phenomena are correlated in one absolute and necessary law, from which they can all be deduced; in short, that in natural science all that we know, we know absolutely apriori. Now, that experiment never leads to such a knowing, is plainly manifest, from the fact that it can never get beyond the forces of Nature, of which it itself makes use as means. . . By this deduction of all natural phenomena from an absolute hypothesis, our knowing is changed into a construction of Nature itself, that is, into a science of Nature apriori. If, therefore, such deduction itself is possible, a thing which can be proved only by the fact, then also a doctrine of Nature is possible as a science of Nature; a system of purely speculative physics is possible, which was the point to be proved.41 The contrast between Schelling’s and Kant’s views is striking. ScheIling would refer physical phenomena to the higher principles of mind (or spirit), and would construct a purely speculative physics on the basis of apriori conceptions. One of the distinctive features of Kant’s approach, on the other hand, is his conviction of the limitation of pure reason as applied to nature. The metaphysics of corporeal nature deals only with the application of transcendental concepts to matter in general, these metaphysical principles constitute a complete system when the empirically given concept of matter is determined by the categories. Such a metaphysics does not, however, constitute a substitute for empirical research. Concrete facts must still be given to us by experience. What such a metaphysics can do, however, is to reveal, in a necessary way, the general aspects of every possible object of physics. Besides securing physics as a science (as above defined), the knowledge of such metaphysical foundations provides a heuristic guiding the formulation of questions to put to nature, and for which the appropriate experiments must be devised. Schelling may have begun with Kant, but his published writings reflect a very different conception of the aims and methods of natural science. Our interest, however, is not in Schelling’s ideas for their own sake, but in their influence on Oersted. In 1799, at the same time he was defending Kant in his doctoral dissertation, he also came across some of Schelling’s works which had been published just a year or two before. At the conclusion of his after praising Kant’s Anjbtgsgriinde, he comments on Schelling’s Ideen zu einer Philosophie der Natur (1797), and his Von der Weltseele, Grundtraekkene, eine Hypothese (1798). der hiiheren He writes that, 4’Op. cit., note 36, p. 49 Physik zur Erkllirung des allgemeinen Organismus 298 Studies in History and Philosophy of Science no doubt deserve attention for the beautiful and great ideas we find in them, but on account of the not very rigorous method by which the author intermingles empirical propositions without sufficiently distinguishing them from apriori propositions the book is robbed of much of its value, especially as the empirical propositions Oersted adduced are often utterly false.“’ came into intimate contact with ideas of Schelling Nuturphilosophen in the period 1801-1803 while he was on a fellowship. He attended lectures by Fichte at Berlin acquaintance as well. At Jena he became friends with heard August Schlegel’s lectures. In a letter to a impressions of Naturphilosophen in general and of again travelling and made Friedrich friend he Schelling’s via several in Germany his personal Schlegel and records his theories in particular. He [i.e. Schelling] wants to give us a complete philosophical system of physics, but without any knowledge of nature except from text-books and without possessing the same rigorousness of philosophical construction as Kant. These people all bring to market halting comparisons and lopsided physical theories, and then they grumble when others will not accept them. I always pester these people with Steffens who has seen nature with his own eyes and thought about her with his own brain.47 As Oersted’s remarks at various points make clear, he opposed Naturphilosophie for its claim to provide knowledge of nature, but appreciated it for its aesthetic qualities. During his Wunderjurhre he came into contact with the writings of Franz von Baader, whose writings on Nature Philosophy are so beautiful that one would wish to make the acquaintance of the author, and often so obscure that one needs it to get the explanation.. He persistently urges that moral and physical nature are most closely connected, and that without such a connection value. In this he accords very closely with [myself].” As this quote on aesthetic, suggests, rather Oersted’s than physical science has no real of Naturphilosophie was based considerations. His remarks about appreciation on scientific, Nuturphilosophie fall into either of two categories. He either praises such writings for their “great beauty”, or else criticizes them for paying insufficient attention to observation and experimentation in the construction of physical science. While it is true that Naturphilosophie had an effect on Oersted, it is important to carefully determine what this influence amounted to. As Esposito writes, “Oersted . . . would not have called himself a Nuturphilosoph reason that he found sympathy only with its attitude toward nature, with its speculative approach to research”.45 for the and not 42SkriJter vol. I, p. 71. 43Brmef,u og iii Hans Christian Orr.~kd, 2 Vols, Mathilde Oersted (ed.) (Copenhagen, vol. I, pp. 81-82. “Ibid., p. 83. 4SEsposito op. cit., note 33, p. 137. 1870), Oersted’s Discovery oJ‘ Electromagnetism That Oersted teaching understood at the University him around 299 the dangers of unchecked of Copenhagen. A student speculation reported is clear in his Oersted telling 1810 that, It is also my firm conviction, and my lectures bear witness thereof, that a great fundamental unity pervades the whole of nature; but just when one has become convinced of this, it becomes doubly necessary to direct one’s whole attention to the world of the manifold, wherein this truth above all finds its confirmation. If one does not do this, unity itself remains an unfruitful and empty idea which leads to no true insight.‘” This emphasis on the close coupling of theory and experiment is also evident in Oersted’s electrochemical investigations in the following years. 3. Oersted’s Electrochemical Investigations Oersted was among the many scientists in 1800 to be stimulated by Volta’s invention of the galvanic battery. Like others, he was interested in the practical uses this battery might be put to, but his interest also extended to articulating a theoretical account of the physics of electrochemical phenomena along Kantian lines. An early expression of this account is presented in an 1806 article in the Journal de Physique on the chemical nature of electrical force.47 More detailed expositions appear in his Ansicht der chemischen Naturgesetze durch die neuren Entdecken gewonnen, published in Berlin in 18 12, and in the revised version of this work published in French translation in Paris the next year under the title Recherches sur I’identitt des forces chimiques et tlectriques.48 The major aim of this work, as the title of the French edition suggests, was to show that chemical and electrical forces are at bottom identical. In the Introduction to the Recherches Oersted compares the state of chemical science to that of mechanics before Galileo, Descartes, Huygens and Newton. Before the age of these men a great number of important facts were known, but the great principle of unity to which the modern science of mechanics owes its completeness was lacking. Chemistry of facts had been collected, a series these affinities had been discovered. to reduce all chemical effects to the that chemical science could be based was in a similar condition. A large body of affinities found, but no first cause of An attempt should be made, he thought, primitive forces which produce them, so on a theory of force whence, by the aid of 49lohannes Carsten Hauch, H. C. Ousted’s Leben. Zwei Denkschrifen van Hauch und Forchammer, H. Sebald (trans.) (Spandau, 1853), p. 13; quoted in Stauffer (1957), op. cit., note 4, p. 39. 470ersted, ‘Sur la propagation de l’klectricitk’, Journal de physique, de chimie, d’histoire naturelle et des arts. 62 (1806). 369-375. 480ersted, Ansich; der chemischen Naturgesetze, durch die neueren Entdeckungen gewonnen (Berlin, 1812). Reprinted in Naturvidenskabelige Skrifer, Vol. II, pp. 35-169. Recherches sur I’identite des,forces chimiques et Plectriques, Marcel de Serres (trans.) (Paris, 1813). 300 Studies in fiistory and Philosophy of’ Science mathematics, the chemical phenomena could be deduced. The Ansicht and Recherches were intended as a first step toward this ultimate goal.“9 In order to unify the phenomena associated with chemical combination, heat, light, electricity and magnetism, Oersted related them to two basic forces extended in space. While retaining the Kantian dynamism, Oersted developed his own version of the Kantian Grundkr~fte. Like Kant, he saw matter as composed of two fundamental forces, but he modified the Kantian forces of attraction and repulsion into the chemical forces of combustion and combustibility. just as the simultaneous existence of attractive and repulsive forces in dynamical equilibrium satisfied the necessary conditions for the existence of matter, so too, Oersted argued, the two forces of combustion and combustibility account for all chemical phenomena, and all mechanical action including heat.50 He then employed these two basic chemical forces, the Brennktxft, in combustible substances and alkalies, and the Ziindkrqft, in oxygen as well as in acids, to explain oxidation, acidification, and neutralization in chemistry.5’ The two basic forces extend, he says, throughout the entire world: all actions in nature represent in various modes of behavior both basic forces.52 Oersted then uses these ideas to explain the physical processes at work in Volta’s battery, suggesting how one manifestation of force is changed into another. He begins by explaining how electrical force is propagated. Electricity does not flow like a fluid, but is rather propagated by a kind of continual decomposition and rccomposition, or rather by an action which disturbs the equilibrium at every moment, and re-establishes it in the following instant. One could express this succession of opposed forces which exists in the transmission of electricity by saying that electricity is always propagated in an undulatory nlanncr.5’ A similar process operates with respect to chemical forces. Chemical elements, such as those present in a battery, are themselves a combination of the two basic forces. The stability of a chemical element is, however, a delicate matter, dependent on an equilibrium between its constituent forces. When this equilibrium is disturbed, for example by an electrical force. the disturbance travels through the battery in wave-like fashion, briefly decomposing the elements along the way, which then return to their equilibrium state. The electrical and chemical forces are thus interconvertible. Which one is manifested depends on whether or not equilibrium is maintained. The conversion of one kind of 49For further discussion, see K. Meyer’s Introduction to Oersted’s Skrlfter, Vol. I, p. xlvii. S0For discussion, see T. H. Levere, Ajfiniry and Matter: Elements qf Chemical Philosophy. 18001865 (Oxford: Clarendon Press, 1971). p. 134. “See Skrifter, II. p. 73. “Skr[fter, II, p, 149. “joersted, Racherches p. 130. For more on this undulatory theory, and the relationship between the ideas of Oersted and Ampere, see the excellent discussion in K. L. Caneva ‘Amp&e, the Ethereans, and the Oersted Connection’. British Journa/ for the History of Science 13 (1980). Oersted’s Discovery of Electromagnetism physical phenomenon explained, Oersted into believed, another 301 apparently by postulating forces. Oersted’s Ansicht and Recherches, further discussions of the metaphysics quite different an underlying one duality is thus of basic it should be evident, were not merely of dynamism as a general foundation for physics. He was already long convinced that Kant had articulated the correct metaphysical foundations of natural science. His chief concern in these books was chemistry, and in particular the formulation of a chemical theory which would provide an answer to Kant’s accusation that “chemistry should be called systematic art rather than science”.54 When Kant insisted that natural science have a formal structure, and not be merely an accumulation of empirical observations, he had chemistry in mind in particular as an example of an area of investigation that had not yet reached the level of a science. The laws of chemistry were merely ‘laws of experience’ (Ecfuhrungsgesetze), that is, they were simply empirical generalizations with no genuine lawlike character. The chemist fills his notebooks with observations, but his knowledge of physical events remained on the sensory level and never contained the apriori laws that governed the processes of chemical interaction. Natural science was Nuturwissenschaft, and Wissenschaft could only mean an ordered system of principles. Knowledge derivative of these principles was to be upodictic. The Ansicht and Recherches represent the results of Oersted’s sustained attempt to derive and describe the fundamental apriori principles which he, like Kant, believed were necessary if chemistry was to become a science.s5 Describing the Ansicht, The Snelders book writes, distinctly shows the influence of Kanatian philosophy, systematic construction, but still more in the dynamical concept Oersted defends. the aim of chemistry is to trace all phenomena forces; chemical phenomena are to be deduced mathematically.5h In doing so, Oersted takes exactly the method defending, reducing namely, phenomena that Schelling partly in its of matter which back to primitive criticized Kant for to their lowest level and then con- structing a mathematical theory for making predictions. As Oersted described his hope in the Ansicht, “Chemistry will then become a science of forces; mathematics will reach into its inmost recesses, to determine the quantitative relations. directions and effective forms of these forces”.” In this way 54Anfangsgriinde,p.4. For further discussion of Kant’s view of chemistry, see K. Okruhlik, ‘Kant on Realism and Methodology’, in: R. E. Butts (ed.), Kant’v Philosoph,: of Phy.~kul Science (Dordrecht: D. Reidel, 1986), pp. 307-329: see especially pp. 3 I I-313. Yjee Esposito, op. cit., note 33, p. 49-50; also, B. Gower, ‘Speculation in Physics: The History and Practice of Naturphilosophie’,Studies in History and Philosophy of Science 3 (1973). 341-342. 56H. A. M. Snelders. ‘Romanticism and Naturphilosophie and the Inorganic Sciences’, Studie.v in Romanticism 9 (1970), p. 205. 570ersted, Ansicht, p. 5; quoted in Levere, op. cit.. note 50, p. 133. 302 chemistry achieved Studies in History and Philosophy would attain in mechanical the same unity and completeness of Science that had already been science. Although the Ansicht and Recherches were primarily about the identity of electrical and chemical forces, Oersted conjectured that other kinds of physical phenomena might be interrelated as well. In particular, “It will be necessary to see if electricity in its most latent state does not have some action on a magnet as such. The experiment will not be without difficulty because the electrical action will always tend to mix in with it and make observation very complicated”.5x The experiment turned out to be the essence of simplicity, although it was to take eight years for the decisive experiment to be performed. 4. Oersted’s Discovery of Electromagnetism Oersted noted that “if it were possible to produce any magnetical effect by electricity, this could not be in the direction of the current, since this had so often been tried in vain, but that it must be produced by a lateral action”.59 That is, others had assumed that if there was to be any magnetic effect of an electric current, the positive and negative ends of the wire would correspond to the north and south poles of a magnet, or vice versa. All investigations had failed to detect any such simple, intuitive relationship. Oersted reasoned that if there was to be any magnetic effect, it would have to be found alongside the current-carrying wire. He goes on to explain why this idea occurred to him. Writing in the third person, he says, This was strictly connected with his other ideas; for he did not consider the transmission of electricity through a conductor as a uniform stream, but as a succession of interruptions and reestablishments of equilibrium, in such a manner, that the electrical powers in the current were not in quiet equilibrium, but in a state of continual conflict. As the luminous and heating effect of the electrical current, goes out in all directions from a conductor, which transmits a great quantity of electricity; so he thought it possible that the magnetical effect could likewise eradiate.hO In the spring magnetism of 1820 a feasible occurred to Oersted, form of the experiment and it was around relating April electricity 1820 that and it was carried out, during his advanced class in electricity, galvanism and magnetism at the University of Copenhagen. It was discovered that if a magnetic needle is brought into the field surrounding the wire, it will set itself tangent to the circular field, continuing its tangential position when it is carried around the wire, pointing in one direction beneath the wire and in the opposite direction above it. Three months after this initial experiment, during July 1820, he 5”Recherches, p. 238; this part is not included in Oersted’s 500ersted, ‘Thermo-Electricity’, in Skrifier II, p. 357. “Skriftcr II, p. 357. Skr(J/er 303 Oersted’s Discovery of Electromagnetism extended his experiments. in the conductor, former position. He found the direction The interposition that if the direction of the needle of various of current is similarly substances is reversed reversed between from its the wire and the needle had no effect on the position of the latter. On the basis of these observations Oersted inferred that the undulatory electric powers in the wire produced a circular motion in the space surrounding the wire, that electric and magnetic forces acted in circles, and that they were spatially distributed. He noted in particular that, “It is sufficiently evident from the preceding facts that the electric conflict is not confined to the conductor, but dispersed pretty widely in the circumjacent space”.6’ On 21 July 1820 he published a condensed four-page Latin account of his investigations, bearing the title Experimenta circa eflectum conjlictus electrici in scum magneticam. As he characterized his discovery later, in this short tract he announced “the fundamental law of electromagnetism, viz., that the magnetical efiect of the electrical current has a circular motion round it”.63 How should we understand why Oersted was led to perform this experiment, and thus arrive at the discovery of electromagnetism? I wish to suggest that this discovery was due more to Oersted’s reading and understanding of Kant than it was to ideas dominant among the Naturphilosophen. The difference resides to a great extent on diferent views of the roles of reason and experiment in the advancement of natural science, as well as on substantive views about the nature of physical reality. First, we know that Oersted embraced Kantian views very early in his studies, and continued to hold Kant in high esteem throughout his life. In particular, he adopted Kant’s vision of a dynamical physics conceptualized in term of forces rather than atoms. This basic metaphysical option informs all of his scientific theorizing. In addition, and equally important, Oersted internalized Kant’s injunction to employ the regulative idea of a fundamental unity of forces in his scientific investigations. It was this idea that played a crucial role in his early electrochemical research and electromagnetism. This was connected with took to heart, to transform chemistry from into a science. It was Oersted’s attempt to subsequently in his discovery of Kant’s challenge, which Oersted a mere collection of observations systematize chemistry in terms of fundamental forces of combustion that led to his conjectures about the interrelatedness of electricity and magnetism, and thence to his electromagnetic experimentation. Second, Kant held that pure reason alone is unable to produce a science of nature, and that therefore careful empirical investigations are necessary. In this “‘Skrzjier I, p. xciii. 62Skr$er II, pp. 214218. 6’.Skrzfler II, p. 358. This is given in English translation in Skrifter I, pp. lxxxix-xciii Studies in History and Philosophy of Science 304 last respect Kant differed sharply from certain other “dealers in the upriorThJ who assumed that empirical research was unnecessary, because pure reason was capable of arriving at a complete knowledge of nature -- &helling, in particular, seemed to suppose this. Oersted’s attitude was much closer to Kant’s than to Schelling’s. Like Kant, Oersted was both more knowledgeable about and more respectful of the actual achievements of physical scientists than were the majority of the Naturphilosophen, &helling included. Both Kant and Oersted agreed that to set natural science on firm metaphysical foundations was a useful, and indeed an essential, task, but that it was certainly no substitute for empirical investigations into nature. The Naturphilosophen were mainly impressed with how much physical knowledge can be arrived at by the use of pure reason. Kant, and Oersted, tended to focus on how little could be achieved by pure reason alone, and thus regarded experimental investigations more highly. This is not to assert, however, that either Kant or Oersted were unconcerned with the formal character of science. As we saw earlier, Oersted follows Kant in holding that a science must meet certain stringent conditions. In short, without putting nature to the test (in virtue of realizing the insufficiency of pure reason), and without the high scientific standards he adopted from Kant, Oersted never would have made the empirical discovery he did. If we are to look for inspirational forces behind Oersted’s discovery, Kant must be considered as more important than Schelling and Naturphilosophie. 5. Summary/Conclusion As Oersted wrote about himself: “Throughout his literary career, he adhered to the opinion, that the magnetical effects are produced by the same powers as the electrical. He was not so much led to this by the reasons commonly alleged for this opinion, as by the philosophical principle, that all phenomena are alleged” produced by the same original power”.h5 By “the reasons commonly he was referring to the allegation that his discovery was merely accidental. But if the above analysis is substantially correct, then his remark might just as well apply to the claim, which has enjoyed popularity more recently, that he was “led” to his discovery by Naturphilosophie. It is true, as Stauffer remarks, that “This belief in the unity of the powers of nature was characteristic of the German Romantic school of Naturphilosophie”.@ But I would not want to go on to endorse his claim that: “It was Naturphilosophie that led to the Rather, as Williams at one point admits, discovery of electron~agnetism”.h7 Oersted “developed his philosophical insights by comparing his own metaphyMThe phrase is from Ellington, op. cit.. note 9, p, xix 6SSkriferII,p. 356. 4, 4. 305 Oersted’s Discovery of’ Electromugnetisrn sits with those of the Nuturphilosophen. Since both Oersted and the Narurphiloand basic ideas from Kant, it is not [surprising] that Oersted’s later philosophy closely resembled Naturphilosophie”.@ But sophen drew their inspiration resemblance is not identity, and the d@erences between those of Nuturphilosophen are in this case more important Oersted’s views and than their superficial similarities. Aesthetically Oersted may have found Naturphilosophie appealing, but it was his devotion to a Kantian philosophy of natural science that was instrumental in his discovery of electromagnetism. Acknowl~~dgrments ~~ I would like to express my sincere gratitude to Gerd Buchdahl, Karl Ameriks, Michael Crowe, and anonymous referees of this journal for helpful comments on an earlier draft of this paper. ‘“L Pearce Williams, ‘Oersted’, in: C. C. Gillispie (ed.), Dictionnry of Scientz~c Biography, Vols iNew York. 197&1980). Vol. IX, pp. 182-183. 16