Science and Reality *
British Journal for the Philosophy of Science, 18 (3)
Nov. 1967, 177-196.
The purpose of this essay is to re-introduce a conception which, having served for two millennia as a guide to the understanding of nature, has been repudiated by the modern interpretation of science. I am speaking of the conception of reality. Rarely will you find it taught today, that the purpose of science is to discover the hidden reality underlying the facts of nature. The modern ideal of science is to establish a precise mathematical relationship between the data without acknowledging that if such relationships are of interest to science, it is because they tell us that we have hit upon a feature of reality. My purpose is to bring back the idea of reality and place it at the centre of a theory of scientific enquiry.
The resurrected idea of reality will, admittedly, look different from its departed ancestor. Instead of being the clear and firm ground underlying all appearances, it will turn out to be known only vaguely, with an unlimited range of unspecifiable expectations attached to it.
It is common knowledge that Copernicus overthrew the ancient view that the sun and the planets go round the Earth and that he established instead a system in which it is the sun that is the centre around which all planets are circling, while the Earth itself goes round the sun as one of the planets. But we do not see it recognised that in the way Copernicus interpreted this discovery, he and his followers established the metaphysical grounds of modern science. We cannot find this recognised, since these grounds of science are predominantly contested today.
The great conflict between the Copernicans and their opponents, culminating in the prosecution of Galileo by the Roman hierarchy, is well remembered. It should be clear also that the conflict was entirely about the question, whether the heliocentric system was real. Copernicus and his followers claimed that their system was a real image of the sun with the planets circling around it; their opponents affirmed that it was no more than a novel computing device.
For thirty years Copernicus hesitated to publish his theory, largely because he did not dare to oppose the teachings of Aristotle by claiming that the heliocentric system he had set up was real. Two years before the
* HHC: Polanyi extensive comparison of Ptolemy’s system with Copernicus has not been reproduced, pp. 180-184 plus part of page 185.
publication of his book in 1543, the protestant cleric Osiander responded to preliminary publications of the Copernican system by a letter pressing Copernicus to acknowledge that science can only produce hypotheses representing the phenomena without claiming to be true. Later, Osiander succeeded in introducing an Address to the Reader into the published book of Copernicus denying once more the reality of the Copernican system. The issue was still the same, more than half a century later, in Kepler’s defence of Tycho Brahe against his critic Ursus, and the same again when Galileo confronted Cardinal Bellarmine and afterwards Pope Urban VIII.
The conflict was settled, at least for secular opinion, when the Copernican system was confirmed by Newton. Copernicus and his followers were recognised then to have been right; and for the two following centuries their steadfastness in defending science was unquestioningly honoured among modern educated people.
I myself was still brought up on these sentiments; but by that time some eminent writers were already throwing cold water on them. The positivist critique of science, initiated by Ernst Mach,  and vigorously supported by Henri Poincaré,  declared that the claim which Copernicus, Kepler and Galileo so bitterly defended was illusory. This radical positivism taught that science consisted merely in establishing functional relations between the data observed by our senses and that any claim that went beyond this was undemonstrable. A reality underlying mathematical relations between observed facts was a metaphysical conception, without tangible content.
During the past half century these formulations of positivism have been first sharpened into logical positivism, which claimed to establish strict criteria for the meaning and validity of all empirical statements. But logical positivism, after reaching its highest prestige in the forties, presently declined for its aims proved unattainable. Its theories were softened down then by a series of qualifications, which amounted to abandoning any attempt at establishing a formal criterion of the meaning and validity of a scientific statement. The rise of analytic philosophy confirmed this abdication by abandoning the critique of science. Thus we are left today without any accepted theory of the nature and justification of natural science.
1. Ernst Mach, Die Mechanik in ihrer Entwicklung (1883).
2. Henri Poincaré, Science et Hypothese, Paris (1902), pp. 140-1, and Henri Poincaré, La Valeur de la Science, Paris (1914), pp. 271-4. In the latter book Poincaré defends himself against being taken to reject Galileo’s affirmation that the Copernican system was true. He identifies convenience with coherence and ascribes to coherence the value of a greater truth than that which Galileo had claimed.
There has been sharp opposition to the positivist movement by individual authors, among them Planck  and Einstein,  as well as the great historian of science, Alexandre Koyré;  but these authors supplied no statement of the true metaphysical foundations of science. This is the situation in which I shall examine the Copernican’s claim that the heliocentric system was a true account of reality. And I shall show that in their conception of reality we can find the actual grounds on which science has rested ever since Copernicus established modern science on these grounds.
[HHC: Fig 1 & related paragraphs not reproduced]
1. See footnote to p. 17.
2. Albert Einstein, Biographical Notes in Albert Einstein Philosopher-Scientist, ed. P. A. Schilpp, New York (1949), p. 49, writes about Ostwald and Mach: ‘The antipathy of these scholars towards atomic theory can indubitably be traced back to their positivistic philosophical attitude. This is an interesting example of the fact that even scholars of audacious spirit and fine instinct can be obstructed in the interpretation of facts by philosophical prejudices. The prejudice - which has by no means died out in the meantime - consists in the faith that facts by themselves can and should yield scientific knowledge without free conceptual construction.’
3. Alexandre Koyré, Les Origines de la Science Moderne, Diogene, October 1956, no. 16, attacks positivism for denying that science has knowledge of reality.
[HHC: pages 180-184 not reproduced]
… [HHC: of Copernicus’s theory]
Everything is now bound together, he claims, and this is a sign that the system is real. 
But why did this claim evoke such protest among his contemporaries, particularly by the clergy? The objection was not raised primarily in defence of the bible, but of the medieval philosophy held by clerics and
1. ‘The motion of the Earth, therefore, suffices to explain so many apparent inequalities in the heavens’ wrote Copernicus in Commentariolus. That coherence is a token of reality, is expressed by Rheticus in his Narratio Prima (1540) by the words: ‘So wise is our maker, that each of his works has not one use, but two or three or often more.’
lay scholars alike, since the day of Aquinas 300 years before. The philosophic view which clerics from Osiander to Bellarmine and lay scholars like Melanchton defended, goes back to Aristotle. It assumed that all basic features of the universe can be derived from necessary first principles; for example, the perfection of the universe required that the course of all heavenly bodies be represented by steady circular motions. Such views excluded the possibility of discovering basic features of nature by the empirical observations of the astronomer; any theory established by representing astronomical observations could only be regarded as a mere computing device, and this applied as much to the Ptolemaic system as to that of Copernicus. Only philosophy was competent to arrive at an understanding of essential reality in nature.
Centuries later the positivists declared once more that science can say nothing about ultimate reality, but theirs was a very different reason, namely that they thought any such claim to be meaningless. Their purpose was not to preserve to philosophy the competence for metaphysical theories, but on the contrary, to purify science from making any such empty claims.
The meaning of these two different attacks on Copernicanism, the medieval and the positivist attacks, and the position of Copernicus himself, can be illustrated by a diagram as follows. [HHC: not reproduced]
(1) In the medieval position first principles bear directly on reality, while excluding science from such bearing. (2) The positivist movement is shown isolating science on the one hand from any extra-scientific first principles and on the other hand from reality, since neither of these is recognised. Science, regarded merely as a convenient summary of given facts, is strictly self-contained. (3) Copernicanism is shown, thirdly, claiming to apply basic principles through empirical science for discovering reality.
Copernicus did not contest the competence of philosophy to arrive at necessary conclusions about the nature of things. When Osiander reminded him that his astronomy fails to explain the motions of the planets,  he must have agreed that these motions could be understood only from first principles and not from his astronomy. His strict adherence to the steady circular motion of heavenly bodies, which made his system inordinately complicated and clumsy, showed him to be basically an Aristotelian. But he was irresistibly compelled by the appearance of his own system to claim that this particular feature of the celestial order, though derived essentially from experience, was true and real. Thus did he make for the first time the metaphysical claim that science can discover new knowledge about fundamental reality and thus did this claim eventually triumph in the Copernican revolution.
Such is the claim of science to know reality, that positivism disowned in our time; and it is this same metaphysical claim, now widely discredited, that I want to re-establish today.
Let me start by asking, what Copernicus meant by saying, that his system was real? What had he actually in mind when believing that the planets really circle the sun? We shall find a clue to this question if we first look at the more active form of this belief which Kepler and Galileo manifested when undertaking their enquiries. They testified to their belief that the Copernician system was real, by relying on it as a guide to discovery.
I shall show this for Kepler. His Third Law, discovered seventy-six years after the death of Copernicus, developed the feature of the heliocentric system, which Copernicus had mentioned as its most striking harmony, namely the fact that all six planets recede steadily further from the sun in the sequence of their longer orbital periods. Kepler lent precision to this relationship by showing that the cube of solar distances is proportional to the square of the orbital periods. His other great discovery -
1. In his Address to the Reader prefacing the De Revolutionibus, Osiander says of the celestial movements, that the astronomer “… cannot by any line of reasoning reach the true causes of these movements…”
ten years earlier - of his First and Second Laws, was in some sense a departure from Copernicus. It broke away from the doctrine of steady circular planetary motions and introduced instead an elliptic path and a law of variable velocities related to the ellipse. Yet this elliptic path, with the sun in one focus of it, was firmly tied to the heliocentric system. It could not have been discovered from Ptolemy’s image of the planetary system.
I would not hesitate to say that these discoveries proved the reality of the Copernicus system, but this is only because I know that Newton discovered towards the end of the same century that these three laws of Kepler were expressions of the law of universal gravitation. At the time at which Kepler put his laws forward, mixed up with a number of other numerical rules that were to prove fallacious, the effect of his three laws was not widely convincing; Galileo himself was unimpressed by them. But for the moment I can set these questions aside, for I am only trying to understand what Kepler and Galileo themselves believed about the Copernican system, when they relied on their conviction that it was real and thus a proper guide to their enquiries.
At first glance it seems easy to see what happened in Kepler’s and Galileo’s minds. Relying on the reality of the Copernican system, they recognised the presence of problems, which by many years of labour they proved to have been fruitful. But this leaves open the question, how the Copernican system could indicate to them good problems that were not visible in the Ptolemaic system.
We meet here a general issue, which to my knowledge, has never been systematically examined. We must ask: What is a problem? Not the kind of problem set to students of mathematics, or to chemists in practical classes, but a scientific problem the solution of which is unknown, and on which the scientist may yet embark with a reasonable hope of discovering something that is new and that will prove also worth the labour and expense of the search.
I would answer that to have such a problem, a good problem, is to surmise the presence of something hidden, and yet possibly accessible, lying in a certain direction. Problems are evoked in the imagination by circumstances suspected to be clues to something hidden; and when the problem is solved, these clues are seen to form part of that which is discovered, or at least to be proper antecedents of it. Thus the clues to a problem anticipate aspects of a future discovery and guide the questing mind to make the discovery.
We may say then that Kepler’s conviction that the Copernican system was real, was expressed by his belief that its image anticipated aspects of something hidden and possibly accessible by an enquiry in a certain direc-
tion. And we may add that he confirmed these anticipations when, by following their guidance, he discovered his three laws.
Nor was this all. For in their turn, Kepler’s discoveries raised new problems in Newton’s mind, insofar as they anticipated aspects of the still hidden laws of gravitation, which Newton was to discover. Thus Newton was guided still further by a belief in the reality of the Copernican system.
The confidence which the followers of Copernicus placed in the reality of the Copernican system consisted, then, in surmising still hidden implications in it, as were suggested to them by certain features of the system. Their belief in the system’s reality was an act of their imagination that spurred and guided them to discovery.
Let us take stock of the position we have reached so far. In the history of the Copernican Revolution we have found it possible to discriminate the explicit statements of a theory from its anticipatory powers. The celestial time-table set out by Copernicus was not markedly different from that of Ptolemy. Close on to a century following the death of Copernicus, all efforts to discriminate convincingly between the two systems on the grounds of their observable quantitative predictions had failed. While the discoveries of Kepler and Galileo based on the heliocentric system greatly increased its plausibility and eventually convinced most astronomers, the general effect, judged for example by the critical responses of Bacon or Milton, was far from conclusive. Yet all this time the theory of Copernicus was exercising heuristic powers absent in the system of Ptolemy. We are faced with the question then how one of two theoretical systems, having virtually the same explicit content, could vastly exceed the other in its anticipations.
In a way I have given the answer to this question in the anticipatory suggestions offered by the Copernican system to the followers of Copernicus. Its anticipatory powers lay in the new image by which Copernicus recast the content of the Ptolemaic system. It is in the appearance of the new system that its immense superiority lay; it is this image that made the Copernican revolution.
I am drawing here a distinction which will prove decisive. I distinguish between the precise predictive content of a mathematical theory consisting in a functional relation of measured variables and a meaning of the theory which goes beyond this. While the functional relations remain the same, the surplus of meaning which goes beyond them may vary, as manifested in this case by the appearance of the theory.
The way this may come about can be illustrated from everyday life. Suppose we have a list of all the towns of England, each with its precise longitude and latitude, and the number of its inhabitants, and we now
represent these data in a map, each town being marked by a circle corresponding to its size. The mapping of the list adds no new data to it, yet it conveys a far deeper understanding of these data. It reveals, for example, the way the population is distributed through the country and suggests questions about the reasons of physical geography and history which will account for this distribution. The map will guide the imagination to enter on fruitful enquiries to which the original list would leave us blind.
E. M. Forster has shown a similar difference between two kinds of characters in a novel. There are flat characters whose behaviour can be precisely predicted and round characters which develop creatively; the latter, says Forster, are more real and hence have the power convincingly to surprise us. By bearing on reality, scientific theories too have the power convincingly to surprise us.
But here I must enter a warning. The distinction between explicit content and informal heuristic powers is profound, but not absolute. No mathematical theory means anything except as understood by him who applies it, and such an act of understanding and applying is no explicit operation; it is necessarily informal. Indeed, great discoveries can be made by merely finding novel instances to which an accepted theory applies. For example, Van t’Hoff’s demonstration that the mass action law of chemistry was an instance of the Second Law of thermodynamics was a fundamental discovery. When I speak of the explicit content of a theory, I refer to such applications of it which are fairly obvious, and I distinguish these from a yet indeterminate meaning of a theory that may be revealed only much later, through a scientist’s imagination.
But was Copernicus himself, when expressing his belief in the reality of his system, in fact asserting that it had anticipatory powers, which the Ptolemaic system had not?
It is not clear how anticipatory powers can be known at all, apart from relying on them as clues to an enquiry. Copernicus obviously did not know that his system represented an aspect of Kepler’s laws and of Newton’s theory of general gravitation; indeed, being wedded to an explanation of the planetary system in terms of steady circular motions, he would have strictly rejected Kepler’s laws and Newton’s theory based on these laws. Yet his belief that his system was real, was basically akin to that of his great successors. For he saw the essence of his system in those features of it which were to serve as clues to the problems of Kepler and Newton. He saw in the increase of orbital periods with increasing solar distance the characteristic feature of a system in which the sun centrally controls the order of planets, and this is the feature on which Kepler and Newton were to build their discoveries.
But there is actually a more general kinship between the commitment of Copernicus to his belief that his system was real and that of his followers relying on it for their problems. What Copernicus believed of this system was what we all mean by saying that a thing is real and not a mere figment of the mind. What we mean is that the thing will not dissolve like a dream, but that, in some ways it will yet manifest its existence, inexhaustibly, in the future. For it is there, whether we believe it or not, independently of us, and hence never fully predictable in its consequences. The anticipatory powers which Kepler, Galileo and Newton revealed in the heliocentric system, were as many particulars of the general anticipations that are intrinsic to any belief in reality.
This defines reality and truth. If anything is believed to be capable of a largely indeterminate range of future manifestations, it is thus believed to be real. A statement about nature is believed to be true if it is believed to disclose an aspect of something real in nature. A true physical theory is therefore believed to be no mere mathematical relation between observed data, but to represent an aspect of reality, which may yet manifest itself inexhaustibly in the future.
We can ask then why the general appearance of the heliocentric system made Copernicus and his followers believe that it was real - why its close coherence, its intellectual harmonies had such power to convince them of its reality. And to this we reply that the existence of a harmonious order is a denial of randomness, and order and randomness are mutually exclusive. Moreover, anything that is random is meaningless, while anything that is orderly is significant. 
To recognise the principle at work here, think of the difference between a tune and a noise; or, more generally, between a message and a noise. Communication theory defines a noise, in contrast to any distinctive series of signals, as random sequence, and it says that, being random, noise conveys no information - means nothing. This implies an important difference in the identifiability of an ordered sequence, as compared with a noise. Any single message is represented ideally by only one configuration of signals, while for a noise the very opposite holds. No significance must be attached to any particular configuration of signals that are a noise; we must indiscriminately identify any one configuration of a noise with any other configuration of it.
This is true of any aggregate deemed random: we must assume that the chance events which compose it could have as well happened otherwise. And, by contrast, once we have recognised an aggregate of events as
1. I disregard here statistical laws, as they apply to another level of reality. (See my Personal Knowledge, p. 390.)
orderly and meaningful, we may not believe that they might as well have happened differently. Such an aggregate is an identifiable thing, possessing reality in the sense I have defined it; namely, that it may yet manifest itself inexhaustibly in the future. To distinguish meaningful patterns from random aggregates is therefore to exercise our power for recognising reality.
Our capacity for discerning meaningful aggregates, as distinct from chance aggregates, is an ultimate power of our personal judgment. It can be aided by explicit argument but never determined by it: our final decision will always remain tacit. Such a decision may be so obvious, that in it our tacit powers are used effortlessly and thus their use remains unnoticed; our eyes and ears continuously commit us to such effortless decisions. But other decisions of the same class may be hard and momentous. A jury may be presented with a pattern of circumstantial evidence pointing to the accused. It is always conceivable that this pattern may be due to chance; but how unlikely a chance should they admit to be possible? Or else, what degree of coincidence should be deemed quite unbelievable? The prisoner’s life and the administration of justice will depend on the decision, and there is no rule by which it can be decided. This is precisely why it is left to the jury to decide it.
I have said that reality in nature is a thing that may yet manifest itself inexhaustibly, far beyond our present ken. Something must be added to this description, if the pursuit of natural science is to be justified. Consider that the Copernican revolution was but a continuation of a structuring that had its origins in antiquity. Copernicus deepened and beautifully clarified a coherence transmitted to him by Ptolemy. And this triumph pointed further beyond itself in the mind of Copernicus. In Kepler, passionately embracing the system of Copernicus, its image was to evoke anew the kind of creative hunger which Copernicus had satisfied by discovering it. And the presence of yet hidden truth worked its way further. To Newton, Kepler’s three laws appeared to hang covertly together and he established this fact by his theory of gravitation, which derived all three laws jointly from the mechanics of Galileo. Nor was this the end, for a quarter of a millennium later, Einstein was to find unsatisfying the coexistence of the Newtonian system with the electromagnetic theory of light, and was to discover an even deeper coherence reconciling the two.
The continued pursuit of science is possible, because the structure of nature and man’s capacity to grasp this structure, can be such as is exemplified by this sequence of discoveries covering two millennia. It does happen, that nature is capable of being comprehended in successive stages, each of which can be reached only by the highest powers of the
human mind. Consequently, to discover a true coherence in nature is often not only to discern something which, by the mere fact of being real, necessarily points beyond itself, but to surmise that future discoveries may prove the reality of the thing to be far deeper than we can at present imagine.
It may seem strange that I insist on a belief in the reality of theoretical suppositions as the driving force to discovery. Such belief would seem a conservative assumption, rather than a source of innovation. The positivist view of science would indeed claim that the major discoveries of modern physics were based on a sceptical attitude towards the framework of hitherto accepted scientific theories. The discovery of relativity involved the abandonment of the current conceptions of space and time, and quantum mechanics achieved its breakthrough by discarding Bohr’s planetary system of electrons circling the nucleus. Einstein himself acknowledged that Mach’s positivist philosophy had inspired his work and Heisenberg’s quantum mechanics was deliberately framed to reduce atomic theory to a functional relation of observable quantities.
These revolutionary heresies may seem to contradict my thesis, but I think they fall in line with it, once I make clearer the opposite extreme of creative procedure, based on a firm belief in the reality of the current framework of scientific theory. We may recognise the prototype of such a feat in the discovery of America by Columbus. He triumphed by taking literally, and as a guide to action, that the earth was round, which his contemporaries held vaguely and as a mere matter of speculation. The egg of Columbus is the proverbial symbol for such breath-taking originality guided by a crudely concrete imagination. I remember having this feeling when first hearing of Einstein’s theory of Brownian motion. The idea that the meandering oscillations of small floating particles seen by a botanist under the microscope, should reveal the impact of molecules hitting the particles in tune with the highly speculative equations of the kinetic theory of gases, impressed me as grossly incongruous. I experienced the same shock of a fantastic idea, when I heard Elsasser suggesting (in 1925) that certain anomalies observed in the scattering of electrons by solids may be due to the optical interference of their de Broglie waves. We had all heard of these waves since 1923, yet were astounded by the fact that they could be taken literally as Elsasser did. 
1. This paper was delivered as a lecture at Duke University, Durham, N.C., in February 1964. James Franck lived at that time in Durham and we met to discuss my talk. Franck began very quietly, almost in a whisper, saying: ‘You know, I am one of those literals.’ He clearly was very pleased. During his great career, spent among conceptual revolutionaries like Planck, Einstein, Bohr, Heisenberg, Schrodinger, Born, he must have often doubted the quality of his own genius and he was glad to find its place acknowledged in [my analysis. I think that among great discoveries the one most purely based on a literal acceptance of current ideas, was Laue’s discovery of the diffraction of X rays; but Langmuir too triumphed by the powers of a literal imagination, and many of Rutherford’s discoveries were based on daringly primitive conceptions.]
HHC: [bracketed] displayed on page 194 of original.
This should remind us that the first great move towards the discovery of quantum mechanics was de Broglie’s idea of the wave nature of matter. This revolutionary idea and Schrodinger’s development of it into wave mechanics, shows no trace of positivistic influences. Add to this, that Max Planck, the founder of quantum theory, actively opposed Mach’s analysis of science and also dissented from Heisenberg’s claim of basing physical theories on directly observable quantities ; and that Einstein himself, whose principle of relativity served as an inspiration to modern positivism, was sharply critical of Mach’s analysis of science as a mere relation of observed facts.  It appears then, that the predominant principle that shaped modern physical theory was not the positivist programme, but the transition from a mechanical conception of reality to a mathematical conception of it, which sometimes coincided with the positivistic programme for the purification of science.
We can thus bring the revolution of the twentieth century in line with the Copernican revolution of the sixteenth and seventeenth centuries. Both revolutions consisted in a stepwise deepening of coherence with a simultaneous extension of its range. The modern revolution differed from its precursor only in establishing mathematical harmonies in place of beautiful mechanical systems.
The mathematical image of reality is more abstract than the mechanical, but its capacity to point beyond its immediate predicative content is similar to that of the mechanical image. I have said that the fact that the wave nature of particles postulated by de Broglie could be confirmed by
1. Max Planck, Scientific Autobiography and Other Papers, Philosophical Library, New York (1949), p. 129, Tr. Fr. Gaynor. (Original title of this essay was ‘Der Causalbegriff in der Physic’ first published in 1948.) ‘It is absolutely false, although it is often asserted, that the world picture of physics contains, or may contain, directly observable magnitudes only. On the contrary, directly observable magnitudes are not found at all in the world picture. It contains symbols only.’ In this essay (p. 139) he also objects to the elimination of seemingly unverifiable statements: ‘I must take exception to the view (a very popular one these days, and certainly a very plausible one on the face of it) that a problem in physics merits examination only if it is established in advance that a definite answer to it can be obtained. If physicists had always been guided by this principle, the famous experiment of Michelson and Morley undertaken to measure the so-called absolute velocity of the earth, would never have taken place, and the theory of relativity might still be nonexistent.’
2. In his Autobiographical Notes 1. C, p. 53, Einstein writes about his re-definition of reality as follows: ‘The type of critical reasoning which was required for the discovery of this central point was decisively furthered, in my case, especially by the reading of David Hume’s and Ernst Mach’s philosophical writings.’ But Einstein did not confirm Mach’s teaching that the Newtonian doctrine of absolute rest is meaningless; Einstein proved, on the contrary, that Newton’s doctrine, far from being meaningless, was false.
diffraction experiments, came as a fantastic surprise to physicists. The discovery of the positron occurred just as unexpectedly in confirmation of a prediction contained unnoticed in Dirac’s quantum theory of the electron (1928).
In my account of the Copernican revolution and of the modern revolution in physics, I have mentioned only in passing the contributions made by new experimental observations. But the examples I gave were typical of the way at this time experiments often followed their theoretical anticipation, the connection being sometimes not recognised at first. Usually, theoretical speculation and experimental probing enter jointly into the quest towards an ever broader and deeper coherence.
This brings up the question, how the actual process of discovery is performed. Much has been written about this with which I disagree, but for the moment I can put my own views only quite summarily. To see a good problem is to see something hidden and yet accessible. This is done by integrating some raw experiences into clues pointing to a possible gap in our knowledge. To undertake a problem is to commit one-self to the belief that you can fill in this gap and make thereby a new contact with reality. Such a commitment must be passionate; a problem which does not worry us, that does not excite us, is not a problem; it does not exist. Evidence is cast up only by a surmise filled with its own particular hope and fervently bent on fulfilling this hope. Without such passionate commitment no supporting evidence will emerge, nor failure to find such evidence be felt; no conclusions will be drawn and tested - no quest will take place.
Thus the anticipatory powers that we have seen at work in historical perspective, arouse and guide individual creativity. These powers are ever at work in the scientist’s mind, because he believes that science offers an aspect of reality and may therefore manifest its truth ever again by new surprises.
In this essay I have tried to define the mental powers by which coherence is discovered in nature. But the coherence achieved by the Copernican Revolution filled with dismay those brought up on the medieval order of the universe. The Earth’s central position which had been the symbol of man’s destiny as the only thinking morally responsible being, was lost. Gone was the divine perfection of an immutable firmament encircling the place where fallen man was ever to strive for salvation beyond this place. ‘It is all in pieces, all coherence gone’, wrote John Donne as early as 1611.
The destruction was deepened by the revival of atomism. Dante had said of Democritos that he ‘abandoned the world to chance’. And Dante
was right. The assumption that all things are ultimately controlled by the same laws of atomic interaction, reduces all forms of existence to mere collocations of ultimate particles. Such is the kind of universe that we have inherited from the Copernican Revolution. In it no essentially higher things exist, nor can intangible things be real. To understand the world then consists in representing throughout all that is of greater significance in terms of less meaningful elements and if possible, in terms of meaningless matter. Accepting such a conception of truth and reality, man is confused by his own lucidity and blighted by his self-doubt.
The anti-metaphysical critique of science marks the stage at which a false conception of truth and reality attacks science itself, from which it had first originated. If we can overcome these false ideals of knowledge in science, this might set an example for our whole outlook and, backed by the very prestige of science, might help to overcome scientism everywhere.
Once the recognition of anticipatory powers in science establishes a conception of reality transcending tangible things, we might be able generally to acknowledge higher entities, intangible and yet real - as real as matter and yet meaningful. We shall recognise thus a cosmic hierarchy in which man has once more his own place.’
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1. The basic ideas of this paper were first stated in Chapter 1, ‘Science and Reality’ of my Science, Faith and Society (1946), and summarised in the introduction to the Phoenix Edition (1964) of that book. For the relation of Copernicus to Medieval thought I have benefited from Ernan McMullin ‘Medieval and Modern Science: Continuity or Discontinuity’, International Philosophical Quarterly (1965), 103. Mr Rom Harré (Oxford) showed me unpublished evidence of Melanchton’s anti-realistic views on astronomy expressed in his violent attack on Averroes. Mr Harré, Professor Samuel Sambursky (Jerusalem) and Mr J. R. Ravetz (Leeds) all read my manuscript and suggested corrections from which I substantially benefited. Dr J. D. North (Oxford) helped me not only by commenting on the finished manuscript, but also before this, by discussions during my final formulation of my historical account of Copernicus. But I am, of course, responsible for all the content of this paper.