1Hans Blumenberg is neither a science historian nor a philosopher of science, but his work, of immense erudition, deals with the history of thought ranging from antiquity to the twentieth century. It is therefore necessary to situate Blumenberg’s work on Copernicus within this vast field of thought where he opposes the Selbstbehauptung thesis of modern times to that of Säkularisation. The case of Copernicus and the Copernican revolution occupy a privileged place in the work of Blumenberg. He has devoted two major works to the study—Die kopernikanische Wende (1965) and Die Genesis der kopernikanischen Welt (1975, 2007⁴). It is this latter tome, which is rather thick and dense, which is the object of our investigations. We will focus our analysis on the special section devoted to the emergence of the actual work of Copernicus, leaving aside considerations that go back to antiquity, as well as those of the effects of the Copernican astronomical reform up until the time of Lambert and Kant.

2Let us first situate the place of Copernicus in the economy of this great work and examine what methodological perspectives are explicitly implemented by Blumenberg. In this way we may better understand how he managed to place at a distance the usual interpretations of the Copernican revolution and justify a new interpretation of what was a momentous event for modern times—one which he invites his readers to consider. We will go on to clarify the path followed by Blumenberg in reconstructing the intellectual contexts that made the Copernican revolution possible, as much in the time before Copernicus as during the development of his own world system. Finally, we will complete our analysis by raising some critical reflections on the strengths and limitations of this interpretation.

I – Reconstruction of a “Copernican world history” and the genetic method

3The originality of Hans Blumenberg’s book on the Copernican world lies in the formulation of a single question: what are the historical conditions that made the emergence of the Copernican world system possible? This is equivalent to asking why Copernicus could not have made his move earlier in history. In other words, what had made it impossible and how did this impossibility evaporate during the first half of the sixteenth century? This implies, as a corollary, the establishment of the actual effects of the work of Copernicus, beyond all the hagiographic rhetoric of his time and the convenient clichés of historical studies during the four centuries that followed the death of the Polish astronomer. This is the fundamental question that serves as the unifying thread of Blumenberg’s book.

4In broad outline, the book is organized into six parts which can be summarized as follows. The first, entitled “The Ambiguous Meaning of the Heavens,” is a reflection on the contemplation of the sky in antiquity—the practice of astronomy with the naked eye and a loving contemplative attitude to the cosmic order, addressing the question, as did Anaxagoras, of whether it is better to be than not to be: that life is worth living if only to enjoy the view of the sky, while the choir of Oedipus at Colonus asserted that it would be better not to have been born. Part II of the book, entirely devoted to the work of Copernicus and which will be the object of our analysis, is entitled “The Opening up of the Possibility of a Copernicus.” Part III, as its title suggests, is “A Typology of Copernicus’s Early Influence]” looking at Osiander and Galileo, with Melanchthon, Rheticus, and Giordano Bruno in between. Part IV, entitled “The Heavens Stand Still and Time Goes On,” examines the transformation of the concept of time as a result of the Copernican revolution, when time left the sphere of fixed stars and became a part of the movements of the earth—at least until the consideration by Maupertuis of our planet’s imperfect sphericity and its flattening at the poles. Part V, “The Copernican Comparative” reviews the role of perspective in the new image of the world, and the cosmologies inspired by it in the eighteenth century, notably those of Lambert and Kant, returning to the question of what is Copernican in Kant’s philosophical turning point. In the sixth and final part, Blumenberg brings his critical gaze to bear on what can be considered truly Copernican in our own time, when the progress of space exploration has allowed us to stand on the moon and take a new look at our Earth. This, for the author, is the opportunity to take up his sword in criticism of those such as Descartes, the Enlightenment philosophers and the positivists, who exalted scientific reason but who ultimately descended into a kind of anthropocentrism. In this sense, they placed themselves in opposition to true Copernicanism.

5Beyond the plan of the work, both chronologically and thematically, it is primarily the historical method implemented by Blumenberg which requires clarification and which is the primary interest of our study. It seeks to break, deliberately, with a history obsessed with the search for precursors, a vain enterprise unfortunately used ad nauseam (Überdruß) until the present day. [1] While it is true that heliocentric systems had been proposed in antiquity (such as that of Heraclides of Ponticus and better yet, that of Aristarchus of Samos), it should not be forgotten that these were rejected by astronomy for over two millennia! This means that Copernicus would have been entirely impossible at that time. Without rejecting the search for the conditions that preceded the emergence of Copernicanism, emerging from what Blumenberg calls Vorgeschichte, [2] it should be set against what he calls the Wirkungsgeschichte, namely the history of that which the Copernican reform produced—its real effects, that is to say, the history of its actual consequences. These two points of view must remain inseparably linked. Note that this dual approach also includes assumptions made by Copernicus himself when addressing the reception (Akzeptation) of his reforming work. If we do not proceed thus, we may end up believing that, at the time, Copernicus represented a kind of “foreign body” in relation to his intellectual environment (in seiner geistigen Umwelt), which, according to some, may explain the rejection to which Copernicanism was subject in the cases of Bruno and Galileo. Blumenberg insists that “this is quite wrong,” [3] because rejections that occurred in the seventeenth century had nothing to do with the historical conditions that existed at the time of Copernicus a century earlier. That Copernicus himself recognized he had predecessors (such as Aristarchus and the Pythagoreans) does not alter the fact, because they in no way lead to his own system, which also had to be reconciled with the metaphysics of Plato and of Aristotle. [4] Copernicus believed in his own system, unlike Erasmus Reinhold who used it without believing in it, to establish his Prutenic Tables. Moreover, if Copernicus was really inspired by his “predecessors,” we must also explain why their ideas were not followed by effects in history. [5]

6If we suppose that the Copernican doctrine gave rise to the principle of inertia (as it figures in Newton’s work, for example), how do we understand that the Copernican reform (which required a new physics) occurred in the absence of this principle and of this new physics? This point thoroughly grounds the problem of how to enmesh the gear wheels (Verzahnung) of Vorgeschichte and Wirkungsgeschichte. While Copernicus is the father of many astronomical calculations, he was not the protagonist of a new physics. Of course, once the principle of inertia is accepted, the Ptolemaic objections to a moving Earth are no longer to be feared. However, it may have proved that the principle of inertia was a pure invention of physics—a mere axiom, inaccessible to experiment.

7Copernicus used a simple and plain style aimed at being understood and accepted by all schools of thought. [6] If he insisted on the sphericity of the Earth, it was to more easily transfer the predicate of a sky of fixed stars to the earth, in order to exchange their properties: that which is spherical can be animated by a rotational movement and the Earth then fits this case. Copernicus hardly ventured at all into natural philosophy, wishing to follow closely the structure of the work of Ptolemy in order to avoid the reproach of having wanted to innovate at all costs.

8Copernicus greatly expanded the size of the universe. If the Earth is not the center of the universe, it should be possible to observe the same stars from a different angle from Earth between one moment and another, six months apart, and then measure the distance to them by triangulation of the fixed sphere to the Sun. However, no measurements made at the time found any such annual parallax. The Peripatetics attributed this absence of annual stellar parallax to the immobility of the Earth at the center of the universe. Copernicus, on the contrary, inferred that the sphere of fixed stars, and thus the universe, must be immense—vastly bigger than previously thought. Blumenberg considers that this enlargement of the Copernican universe has nothing to do with the “desire for the infinite” characteristic of the Renaissance. The universe of Copernicus has an indefinite size in the sense that its dimensions are beyond measure.

9The Copernican reform cannot be presented as simply the product of various series of factors converging in the De Revolutionibus, as it is truly a landmark work. Neither can it be presented as the necessity of overcoming the weaknesses of traditional systems giving rise to innovations. History gives us very few examples of this.

10No, the mother of invention [7] is liberation from rigid principles which preclude any possibility of criticism or thought experiment. Most of the time, it is impossible actually to track the movements of thought which led to significant and lasting ideas. We must instead ask how, historically, that which was impossible or intolerable or excluded before, was finally allowed into the sphere of thought and ultimately taken into proper consideration:

11

This Vorgeschichte of potentiation, the opening of theoretical freedom is, in its character inseparable from Wirkungsgeschichte, the strictest definition of historical interest. [8]

12Blumenberg notes that there is a history of the effects of Copernicus, while no such account exists for Aristarchus of Samos. When we speak of “latitude” for the changes possible, that is, the range of possible variations within a system, there are also theoretical actions that are excluded. Depending on the margin of possible variation (narrow or not), a system is stable or unstable, but a system must be able to achieve homeostasis (Blumenberg speaks of “nootope” on the model of the “biotope”). The question of latitude in the Copernican reform (as a background determinant) does not lead to the search for “precursors,” unless they are used as indicators for the expansion of possible variations. It is not for any other reason that most of the “precursors” of Copernicus that have been cited were never known to him either directly or indirectly:

13

The achievement of knowledge is driven from the rear, under the internal pressure of its operation, and not from the front by the destruction of those of its supposedly valid statements, (Gültigkeiten) which have become outdated. [9]

II – Review of historical conditions (Vorgeschichte) prepatory to the emergence of Copernicus

14Blumenberg discusses Duhem and Gerhard Ritter [10] who showed, in their work on late scholasticism, that the Parisian nominalists (Ockhamists) of the fourteenth century were precursors to the Copernican reform. In truth, these medieval discussions did not seek to determine the center of the universe, but to produce thought experiments aimed at testing the agreement between the astronomy current at the time and the assumptions of Aristotelian physics. They mainly discussed the difference between the geometric center (centrum quantitatis) and the physical center (centrum gravitatis) [11] and the potential instability of the Earth caused as the four elements struggled to approach the center.

15Against Duhem, Blumenberg argues that it was a question of oscillations in the Earth’s axis, and in no way an attempt to rebuild the entire system. Buridan, who had asked about the possibility of the axial rotation of the earth (not the sky), only wanted to show that the problem cannot be resolved by natural philosophy, while the question simply did not arise in the mathematical models of astronomers, remaining inaccessible to all knowledge. Here, the history of the late Middle Ages provides nothing that can be considered as heralding the work of Copernicus.

16Against Edward Rosen, the great Copernican specialist, Blumenberg says that we cannot accept the idea that “Copernicus might have happened at any moment in time after Ptolemy.” Blumenberg replies:

17

Rather, an investigative space opened up to a radical critique of the geocentric cosmological schema, from a profound change in the foundations of the explanations of Nature […] [that is] in the ideas of space, time, movement, and causality. [12]

18Hence the statement:

19

So I have to show that the philosophy of nature sanctioned by the total system of scholasticism would not have accepted a solution of the fundamental questions of astronomy in the direction of the Copernican reform. I have to show, moreover, how the internal consistency of the scholastic system as well as the changes it implies lifted this blockade on any correction concerning the fundamental cosmological conception, or at least made it possible to circumvent it (umgehen.) [13]

20In the twelfth and thirteenth centuries, the whole universe was causally linked from the exterior towards the interior in a “centripetal” manner. It was commonly believed that everything depended on the motion of the sphere of the fixed stars, the outermost sphere, whose motion drove the rest of the crystalline spheres, nested concentrically. All of this was set in motion by the “first unmoved mover,” the Peripatetic equivalent of the concept of God in Christian theology, which thus proved the existence of God and made it possible to deduce His metaphysical attributes.

21In scholasticism, this approach also follows a scale of nobility in physical reality: “Sursum unde est motus.” [14] However, the Copernican reform renders that scholastic scheme impossible. On the contrary, the Copernican diurnal rotation progresses “from the earth upwards.” Here, there is clearly a reversal of the scholastic scheme which was entirely unacceptable for the peripatetic philosophers:

22

This observation shows us how and why modernity (die Neuzeit) found in the work of Copernicus the most evident cut-off point (Einschnitt) from the Middle Ages and the most obvious sign of a break with scholasticism. Copernicus had concentrated the actual movements of the cosmos into the innermost region thereof. This could be considered as the paradigm of a gain in immanence, a protection of nature against the uncertainties and intrusions of transcendence. The sky in motion [considered] as a simple reflection of reality, linked to the Earth—that was an infallible thread to be followed. [15]

23The physics of Aristotle had no law of conservation. Only absolute rest was conserved and movement had to be explained at all times and in all cases by a causal factor: “Omne quod movetur, ab alio movetur.” [16] Blumenberg stresses that this scholastic axiom has a particularity in the Latin language, which does not distinguish between the passive voice and the middle-passive of the Greek, and where “to be in motion” is equal to “to be moved,” which is not conducive to the conception of motion as a state, but rather as something that is dependent on an action or a reality.

24From there, Blumenberg develops “contingency” (a term of Aristotelian origin) as taken up by medieval philosophy. The Earth, with its four elements, and which does not follow the regular pattern of the heavens, brings man to the awareness of the need for salvation and away from the search for earthly happiness. The “created” is contingent, it is true, and doomed to destruction. Only divine will maintains it. Blumenberg specifies:

25

The universe is, as regards the origin of its actual reality, for its entire constitution, and in any of its states at any time, dependent on an act in accordance with the consent of the transcendent. [17]

26Since Augustine (who insisted upon “divine will” concerning creation), the ex nihilo creation of a unique moment had called upon the auxiliary concept of “creatio continua.” Here again, in the thirteenth century, a Copernicus would have been unable to break the internal consistency and stability of the scholastic system. Moreover, while opposing himself to the medieval vision, Copernicus seems not to have realized that the need to maintain the movement of the heavenly bodies at all times (des ständigen energetischen Bedarfs) is not included in his system. Only Kepler was aware of this problem: it is not enough to reverse the order of appearance, it is still necessary to explain the dynamic relationships. The dynamic system of Kepler proceeds from inside to outside: that is to say from the center of the universe (the Sun).

27Moreover, the choice of geocentricism was in no way dictated, initially, by issues of religious faith. If the Copernican reform was impossible in the Middle Ages, it was not because of theological inertia, but because Copernicus could not claim to have attained the truth in the face of the coherent and complete nature of the scholastic system.

28

It is important to me to show that the resistance to Copernicanism through recourse to biblical texts, during the Reformation as well as the Counter-Reformation, was not due simply to medieval persistence in the exclusion of all and any changes to the cosmological system. […] On the contrary, […] it was due to the liquidation of a system from within—and that must mean from the center of its theological motivations—that the impossibility of a medieval Copernicus transformed into a possibility. It is this process of expansion of the investigative space, starting from the relaxation of the structure of a system—as a result of the accentuation of specific theological themes—that must be described. [18]

29The Aristotelian-Scholastic concept of causality cannot accept that a process may be a state. It requires, for each phase of movement or change, a factor that intervenes immediately. Blumenberg adds: “I characterize this fundamental idea as a ‘companion causality’ (begleitende Kausalität).” [19] In cosmology, this excludes “actio per distans.” The Middle Ages were as yet quite distant from ideas of inertia or gravitation. Nevertheless, these two ideas were only developed after the Copernican reform. The answer is that in the late Middle Ages, two concepts arrived: 1. the appetitus Partium (for gravity); and 2. the impetus concept (for inertia).

30Blumenberg then embarks on a long rapprochement between the theology and physics of the late Middle Ages, discussing the case of the action of God through the sacraments (Pierre Lombard) and the discussion of this theme in 1320 by Franciscus de Marchia in his Commentary on the Sentences of Pierre Lombard, where he takes the example of projectile motion, borrowed from natural philosophy. [20] In the case of projectile motion, there is a real separation of the motive force of the launcher and the medium through which the projectile moves. Similarly, grace is imparted by the sacrament but it can be active only at a moment remote from the time of receiving it. Franciscus de Marchia deviates from Aristotle to the extent that, according to him, it is no longer necessary to have direct contact between the moving and the moved—“causality is transferred to the moved body itself.” [21] He applies a principle of economy by eliminating unnecessary intermediaries. Causality transferred (übertragene) causes the movement, “violent” (or forced) at its origin, to extend into a natural movement. This would be important later, in order for the Copernican argument in favor of the “natural” motion of the Earth to no longer be threatened with destruction. Specifically, any motive force imparted is what scholastic physics named “impetus.” The preparatory history (Vorgeschichte) of impetus has many source documents, but the payoff is meager compared to what is known of its reception by Thierry of Chartres and even Augustine.

31Jean Buridan was the most important and the boldest thinker of the Parisian nominalist school in the mid fourteenth century, [22] as the originator and developer of the link between the theory of impetus and cosmology, at the same time making unnecessary the doctrine of motive intelligences. [23] It was he who challenged the Aristotelian distinction between natural motion and violent motion, pointing out that the natural motion of falling presupposes a violent movement that has previously lifted the gravitating object away from its natural place. Buridan conceives of natural motion as an inclination, that is to say that the heavenly bodies are “so to speak mobile in and of themselves (quasi per se mobilia),” which visibly prepares the way for the arguments of Copernicus, for whom the earth moves by virtue of its form, and the fact that it is a celestial body.

32Thus cosmology is deprived of a proof of the existence of God and the attributes of the infinite so dear to the Middle Ages, because there is no need of a first unmoved mover with infinite power to move the celestial spheres eternally. [24] However, it should be noted that Parisian nominalism had, in its intentions, a conservative attitude toward the Aristotelian/Scholastic system. All changes proposed in physics and cosmology were considered as adaptations or repairs to the old system. [25] This is the case with Buridan who introduced the impetus into cosmology, breaking the distinction between sublunar physics and supralunar cosmology.

33For his part, Nicole Oresme, [26] another Parisian nominalist, refused to extend the impetus to cosmology and preferred to accept the proper motion of the earth, going so far as to pervert the cosmology of Aristotle to save his physics. Oresme showed that the term “natural movement” is ambiguous, because both natural movements (up and down) presuppose the existence of a violent movement that separated the element from its natural place. [27] However, it remains difficult to explain under Aristotle why the natural movements of the sublunary world have not yet reached their end. To harmonize the Aristotelian system, Oresme accepted the motion of the Earth as a “by-product (Nebenprodukt)” because it does not follow from either cosmology or physics, but is invoked to repair the doctrine of the elements. [28] He wanted to save the Aristotelian idea that each element can have only one natural movement: the movement back to a natural place is a movement “outside nature,” as he put it. There is no double natural movement, only natural movements, violent movements, and movement outside nature. The idea of the motion of the Earth is proposed “in passing,” but not as a reality. This certainly does not mean that Nicole Oresme thought to “jump over the step” that leads to Copernicus, that is to say, to get from a daily axial rotation considered hypothetically, to an annual orbital motion of the Earth around the Sun. Rather, it is a dead-end (eine Sackgasse) in a historical narrative looking for a precursor at any price.

34The 219 bans of the Bishop of Paris, Étienne Tempier, made in 1277, emphasized the omnipotence of God and the contingency of the world, and sought to break from the God of Aristotle who was “thought thinking itself.” The bans lifted dependence on God vis-à-vis the cosmic order by highlighting his omnipotence, making it possible for man to speak directly to God. This is what Blumenberg calls “the principle of immediacy” (das Unmittelbarkeitsprinzip) which would be an outcome of the Paris nominalism of the Protestant Reformation and the Copernican reform. Indeed the refusal of impetus by Oresme corresponds to the developments he advances concerning the divine attribute of omnipresence:

35

What we have considered here as preparation in the field of natural philosophy of the space of possibilities in this Copernican game; as a change in that which prepares the reception of Copernican ideas, becomes, in the history of the real post-Copernican effects (Wirkungsgeschichte), a component of affinity with regard to Copernicus. It becomes clear that the new structure of omnipresence and immediacy prepares the radical implementation (Vollstreckung) of the pantheism of Giordano Bruno as much as the late agreement with Reformed theology. This is demonstrated by the very important and widely distributed book by the Bishop of Chester, John Wilkins, Discourse Concerning a New Planet (London, 1640). [29]

36This preparation goes back, then, to Parisian nominalism, freed of the limitations of Aristotle. If Wilkins defends Copernicus appreciatively, it is because he has provided further confirmation of the immediate relationship of human and earthly realities with their origin.

37The goal which Blumenberg set for himself concerning the history of philosophical thought in its role as the foundation of modern science, was not to present the provenance nor the development of certain ideas and hypotheses, but:

38

to start from a deeper layer, the birth of the investigative space in which these new conceptions became totally possible, and within which were born both the affinities which conferred upon them their effect and the means to express them. This does not answer the question, “How was the Copernican system born?”; it only removes the isolated nature of this question in relation to assumptions in virtue of which Copernicus did not become an Aristarchus of the sixteenth century, that is to say, without effect. What was presented as a sketch is the story of his freedom, but also the way he took into consideration what his contemporaries were capable of understanding: this was a remarkable consideration which is simply a part of what remains to be discovered in his work. [30]

39What matters to Blumenberg is not to assert the need for Copernicus, but the foundation of his pure possibility:

40

This also means that Copernicus was not only a liberator, to the extent that it is he that the self-awareness of modern times should consider and envisage as a hero, over against the Middle Ages. [31]

41Denizens of modern times have invented the category of creative genius in order to try to understand the origins of their own time. But this is no more than a story comparable to the tales of Baron Munchausen. The greatness of Copernicus is not reduced by the fact that he appropriated a freedom that was already in existence and established during the late Middle Ages. This turning point (Wendung) happened neither by spontaneous generation nor because of a genius introduced by fiat from the outside.

III – Testing the “immanent history” of the birth of the Copernican theory

42Blumenberg returns to “Renaissance Platonism” [32] and its metaphysics of light, giving the sun a privileged position. According to him, it would hardly have prepared the way for Copernicanism, being mired in an astronomical impasse. Research into Copernicus has for too long claimed that Copernican heliocentricism was prepared for by the intensification of pagan enthusiasm for the Sun, characteristic of the Renaissance. Copernicus, it is true, reserves the central position for the Sun. In chapter 4 of Part II, Blumenberg does not miss the chance to note that Copernicus’s library contained the work De sapiente, by Charles Bovelles (published in Paris in 1510), and that Copernicus’ copy of De intellectu contains marginal notes, in his hand, in which he accuses Bovelles of not understanding Nicolas de Cusa concerning the sun. [33] However, Blumenberg notes that, in his De sapiente, Bovelles shows that the centrality of man is not so much spatial as symbolic. He also cites this phrase from Chapter 26: “Man was made in the middle of the World outside of all things,” on which Blumenberg comments as follows:

43

Bovillus speaks of the intellectual situation of man. If man must remain at the center of the world in virtue of the product of his reason (Vernunftleistung), he must renounce the physical manifestation of this fact in geocentrism. In Bovillus, Copernicus was able to read the intellectual image that bears the imprint of the paradoxes of de Cusa, according to which man, as he finds himself in the middle of the World, is located outside of all things as if the rest of the world comprised the firmament for him—“in medio mundi extra omnia factum esse hominem.” [34]

44Hans Blumenberg has gone to considerable lengths to show that anthropocentrism is not necessarily related to geocentricism. [35] This is his way of showing that Copernicus was in agreement with the humanistic perspective that places man at the center, but at an idealized center, [36] not to be confused with the central place in the universe. This Copernican anthropocentrism is primarily the idea that truth is accessible to man, and the idea (clearly expressed in the De revolutionibus) that it is “for us that the universe was built, by the best and the most perfect of artists.” [37] It is this idea that Blumenberg evokes when speaking, as we shall see, of the teleological competence of man concerning his knowledge of the universe. [38]

45Blumenberg introduces an essential remark on Ptolemy’s Almagest. He rightly points out that Ptolemy wondered whether he should place the sphere of the Sun above the sphere of the Moon, Mercury, and Venus, or below all planetary spheres, but immediately above the sphere of the Moon. Ptolemy added that the alternatives could not be determined only by means of astronomy. Here Blumenberg refers to the Almagest, without giving references. [39] The problem had not been solved before the arrival of Copernicus even if Ptolemy had arbitrarily opted for a certain arrangement of the Sun, Mercury, and Venus. By admitting the possibility of doubt, Ptolemy had provided new possibilities in pre-Copernican astronomy. Blumenberg adds:

46

My thesis now is that Copernicus started from this undecided point of superior or inferior conjunction [40]

47Blumenberg insists upon the astronomical facet of Copernicus’s choice while recalling that, according to the teleological competence of man in his knowledge of the universe, there must be an answer that makes it possible to justify the authority of Ptolemy while also justifying his astronomical indecision. Issues of learning and dissemination concerning the “Egyptian system” (that of Heraclides of Pontus, with Earth at the center of the world but Mercury and Venus turning around the Sun) are of secondary interest here, not being a source of inspiration for Copernicus. The scholarly references of Copernicus do not prove that his ideas were drawn from the Ancients. When Copernicus does actually speak of the genesis of his system, it is in the Letter-Preface of the De revolutionibus orbium Coelestium, 1543, to Pope Paul III, to whom the work is dedicated—that is, at the moment where he was the least free in his expression. This proves nothing more than that he sacrificed the humanist mode by referring to the Ancients. [41] Blumenberg is looking, rather, for the logical sequence that incorporates these sources of inspiration as scholarly references. If Venus and Mercury revolve around the Sun, the system becomes untenable because the Sun is caught between two systems of planets—and thus a deep reconsideration of the entire system is required.

48What presided over the shaping of Ptolemy’s system (including that which prompted him to place Mercury and Venus where he eventually did), is that it is based on time, that is to say on the length of revolution (and not on the angular distances of the two planets from the Sun): Moon 27⅓ days, Mercury 88 days, Venus 225 days, Sun 1 year, Mars 2 years, Jupiter 12 years, Saturn 30 years. On this point, Copernicus followed the same procedure as Ptolemy, even if he had immobilized the sphere of fixed stars and set the Earth in motion instead of, and in the place of, the Sun. [42]

49Copernicus accepts this temporal ordering principle for the planets, but he refuses that it should be at the price of a preposterous spatial complexity. It was all possible, but only if the Moon was excluded from the series. Once the permutation of the Earth-Moon pair, in place of the Sun, was made, Copernicus thereafter follows the temporal ordering principle of planetary orbits proposed by Ptolemy. By doing so Copernicus goes beyond Heraclides of Pontus and even Tycho Brahe, who was born later.

50Blumenberg takes, as a counter-test of his thesis that an admission of the diurnal rotation of the Earth does not lead to that of its annual motion, the case of Copernicus’s contemporary, Italian astronomer Celio Calcagnini. [43] Although he accepted the diurnal axial rotation of the Earth, Calcagnini absolutely failed to make the leap from diurnal motion to the annual revolution of the Earth:

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If this observation was correct, […] it should allow [us to put forward] at least one negative hypothesis explaining how Copernicus could not have proceeded. The common assertion of his first historians and his later interpreters is false, the assertion being that, for him, the “first movement” he attributes to the Earth must also have been the first idea that he followed in the early stages of his reform. However, if what we have firmly established is correct, then the theory of diurnal motion would only have been advanced as a consequence, arising from the solution of the initial question concerning the ordering of the bodies in the planetary system and the admission of the annual movement that it implies. [44]

52Blumenberg cites a phrase in Copernicus’s Commentariolus which demonstrates this meaning:

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Do not believe that this assertion that the Earth moves is made lightly, as is the case with the Pythagoreans—you will find in this “description of circles” a strong argument for this movement. [45]

54Unfortunately, Blumenberg very quickly passes over Copernicus’s reflections regarding the possible infinity of the universe. [46] Rather, he insists that he has “immobilized the sphere of fixed stars” and that the universe, at least the visible universe, is spherical, that is to say closed. Blumenberg adds another reason in support of his own thesis by noting that Copernicus, in his Commentariolus, presents the “annual motion of the Earth around the Sun” [47] well before discussing the other movements of the Earth. Very honestly Blumenberg clearly concedes in passing that the appearance of the geo-heliocentric system of Tycho Brahe, thirty-five years after the death of Copernicus, “appears as an anachronism.” [48] Here Blumenberg acknowledges that his own interpretation faces a serious difficulty in the development of his Wirkungsgeschichte.

55Moreover, after referring to the difficulties Copernicus had with the epicycle of Venus (which, according to his own measurements, risked compromising the nesting concentric spheres of his own system) Blumenberg shows that Copernicus found himself obliged to take liberties with the principles of Ptolemy. Much more modestly, Blumenberg admits that his thesis can only “infer the immanent history of the Copernican theory” based on some of the philological elements of the De revolutionibus. [49]

56Blumenberg finally shows that he is aware of the limitations of his own interpretation stating: “The genetic hypothesis which I have described here is based primarily on Chapter X of Book I of De revolutionibus.” [50] This contrasts with the practice of commentators who have traditionally relied upon the letter-preface to Pope Paul III to address the issue of the origins of the Copernican system, a forum where, as we have previously noted, Copernicus was less free in his remarks. [51] For his part, Blumenberg claims that while Copernicus was writing chapter X, he did not yet have the intention to publish—he was therefore more free to speak, having written it between 1522 and 1525 at the latest. This assertion is very difficult to verify and is susceptible to being branded an “ad hoc” hypothesis.

57The two respective works of Ptolemy and Copernicus follow a similar progression in their first eight chapters. Ptolemy had consolidated his astronomical theory by ensuring that terrestrial physics could not influence the astronomical discussion. For his part, Copernicus tried to protect his astronomical theory against the dangers that the terrestrial physics of his time could pose to the integration of the Earth into astronomy. For both astronomers, it was essential that physics should not disturb astronomy, the domain of uniquely celestial phenomena. Copernicus shows in Book I of his De revolutionibus that the movement of the earth is “physically possible,” before stating that it is real, but he provides no information on the genesis of his own conception of this world system. It is clear that Copernicus clearly assimilated the contents of the Almagest, even as he strove to make his “adaptation” acceptable to his contemporaries, if such we can call the transfer of the Sun to the center of the world. [52]

Conclusion

58To close our analyses, we would like to draw some lessons from the interpretation of Hans Blumenberg to shed new light upon the work of Copernicus. First, Blumenberg is particularly familiar with the texts analyzed as well as their respective cultural contexts, whose significance he does not distort. His original, rigorous, and prudent methodology prevents him from advancing purely arbitrary assertions, the Wirkungsgeschichte allowing a “control” (verification) of the Vorgeschichte and to find the meaning of a genetic approach which is neither trapped in a simplifying continuism, nor as abrupt as Kuhn’s conception of the history of science, where the “paradigms” are incommensurable with each other. He expressly states his thesis of the “self-affirmation” of the individual person who is thus the starting point of modern times. On this point, Blumenberg is rather close to Cassirer. Indeed, the heir to the Marburg school had characterized the Renaissance as the Selbstbehauptung of man, that is to say, as “the affirmation of the self-sufficiency of secular culture.” [53] However, Blumenberg does not fully follow Cassirer in his interpretation of the genesis of the Copernican doctrine insofar as the latter considered that the return of Platonism during the Renaissance had played a decisive role in this regard. Neither does Blumenberg follow Cassirer when Cassirer assigns, like his mentor, Hermann Cohen, a vital importance to the idea of infinity in the Renaissance. In his book on the Renaissance, Cassirer had opposed medieval man to Renaissance man, whose “self-assertiveness” gained momentum only in the face of the immensity, even the infinity, of the universe:

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The infinity of the cosmos not only threatens to limit the “I” but to reduce it to nothing, and yet in that infinity lies the source of its constant elevation—the spirit is one with the world that it conceives. [54]

60It is quite understandable that Blumenberg did not wish to follow the path of Cassirer (and even Koyré [55]) as that direction still relied, in part, on the thesis of the secularization of divine attributes which he intended to refute down to the smallest detail. Indeed, Cassirer concluded his great book on the Renaissance with these words:

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All these predicates that divinity claims unto itself will now be attributed, in the same fashion, to the human soul. […] The “I” is as grand as the infinite cosmos, since it is in oneself that are found the principles for knowing it in all its infinity. [56]

62Blumenberg, on the other hand, devotes only very limited space to the treatment of infinity in the Renaissance [57] although his constant fight against the stale thesis of “secularization” may have led to further developments on this question. Nevertheless, Hans Blumenberg has managed to completely renew the interpretation of the Renaissance and modernity by placing it within a general philosophical conception of European culture, of which Copernicus remains one of the most prominent figures.