The Necessity of the Universe Christiaan Huygens's Cosmotheoros (1698) and its philosophical and literary backgrounds: an intellectual testament Joas van der Schoot The Necessity of the Universe Christiaan Huygens's Cosmotheoros (1698) and its philosophical and literary backgrounds: an intellectual testament J.A. van der Schoot student nr. 3060888 [email protected] September 2011 Research master thesis Supervisor: dr. J.W. Spaans (Utrecht University) Second reader: dr. E. Jorink (Huygens Institute, KNAW) Cover image: Diagram of the solar system, including the moons of the planets. Cosmotheoros (1698). Contents Short titles and abbreviations 3 1. Introduction 4 Part I . Cosmic fiction and the plurality of worlds from antiquity to the Renaissance 2. Literature: celestial voyages and cosmic visions 10 2.1 Celestial voyages and cosmic visions as moral and metaphysical metaphors 10 2.2 Lucian: lunar literature and satire 13 2.3 Plutarch: myth and philosophy in the world in the moon 16 2.4 Conclusion: classical literature connected to seventeenth-century cosmic fiction 18 3. Philosophy: the (dis)order of the cosmos and the plurality of worlds 21 3.1 Atomism and the infinite universe 21 3.2 Aristotelian cosmology and the rejection of the plurality of worlds 25 3.3 Medieval discussions on the plurality of world 29 3.4 The reinvention of the infinite: Nicholas of Cusa and Giordano Bruno 33 3.5 Conclusion: the non-existence of the plurality of worlds tradition 40 Part II. New Worlds: plurality in seventeenth-century literature, philosophy, and science 4. The plurality of planets and the new sciences 43 4.1 Johannes Kepler and the heliocentric universe 43 4.2 Bishops on the moon: Francis Godwin and John Wilkins 46 4.3 The Scientific Revolution and mechanistic natural philosophy 53 4.4 Cartesian controversies in the Dutch Republic 1640-1700 57 4.5 The Book of Nature 60 4.6 Fontentelle's Entretiens sur la pluralité des mondes 62 4.7 Conclusion: the plurality of planets and solar systems 68 1 5. Cosmotheoros : analysis 70 5.1 Approaches to the Cosmotheoros 70 5.2 The plea for planetary life: similarity and probability 70 5.3 The foundations of scientific knowledge 75 5.3.1 Huygens's concept of probability 75 5.3.2 Epistemological backgrounds 76 5.4 The uniformity of Nature 80 5.4.1 Causality, plurality, uniformity 80 5.4.2 Design and practical teleology 83 5.4.3 The challenge of variety 88 5.5 God and/or Nature 90 5.5.1 The best of all possible worlds 90 5.5.2 God and the design in nature 95 5.5.3 Providence, or the necessary uniformity of Nature 101 5.6 Of Man 104 5.6.1 Mankind in the universe 104 5.6.2 The glory of Man 106 5.6.3 Huygens's intellectual testament 109 5.7 Conclusion: Cosmotheoros and the plurality of worlds tradition 112 6. Conclusion 114 Bibliography 116 2 Short titles and abbreviations Christiaan Huygens's published and unpublished writings have been collected in the Oeuvres Complètes de Christiaan Huygens, published in 22 volumes between 1888 and 1950 in The Hague. This enormous work was commissioned by the Dutch Society for the Sciences, and edited by D. Bierens, J. Bosscha, D.J. Korteweg, and J.A. Vollgraff. The edition is in French, and the sources are presented in the original French, Latin and Dutch, sporadically accompanied by a French translation. The first ten volumes contain Huygens's correspondence. Volume XI to XXI contain Huygens's other published and unpublished writings and are ordered thematically and chronologically. Volume XXII contains 'varia' and a concise biography that sums up the facts of Huygens's life. To the subject of this thesis, especially volume XXI (Cosmologie, ed. J.A. Vollgraff, The Hague 1944) is of interest. This is the volume that contains Huygens's cosmological works, including the Cosmotheoros, accompanied by a French translation of the Latin; and some of his unpublished writings from the period (1686-1690) touching upon cosmological themes. As the source of my citations from the Cosmotheoros I have used an English translation published in 1698 in London by the printer Timothy Childe. I have used the following abbreviations and short titles for citation from the Oeuvres Completes: OC, X, n Oeuvres Complètes, Volume, page. Kosm. Kosmotheoros, sive De Terris Coelestibus, conjecturae, etc. OC, XXI, 653-821. QD Que penser de Dieu? [1886 et 1687?]. OC, XXI, 339-343. Pensees Pensees Meslees. [1686]. OC, XXI, 345-371. DRI De rationi imperviis. De Morte. De Gloria. [1690]. OC, XXI, 509-528. Réflexions Rélexions sur la probabilité de nos conclusions et discussion de la question de l'existence d'êtres vivants sur les autres planètes. [1690]. OC, XXI, 529-568. Other abbreviations and short titles used: CW The Celestial Worlds Discover'd: Or, Conjectures Concerning the Inhabitants, Planets and Productions of the Worlds in the Planets. Written in Latin by Christianus Huygens, And inscrib'd to his Brother Constantine Huygens, Late Secretary to his Majesty K. William. London, 1698. (Facsimile reprint, London 1968) I also used short titles to cite other primary sources. Page numbers refer to the editions found in the bibliography. Finally, after the first citation of the works of Bernard le Bovier de Fontenelle and Baruch de Spinoza, only the short titles are noted. 3 1 Introduction In the year 1698, a remarkable book by Christiaan Huygens (1629-1695) was posthumously published in The Hague by book dealer Adriaan Moentjes. The work was titled Κοσμοθεωρος, sive De Terris Coelestibus, earumque ornatu, conjecturae. Ad Constantinum Hugenium, Fratrem. It was unlike anything else that the Dutch Republic's greatest scientist had ever published. Composed in the form of two letters addressed to his brother Constantijn and written in Latin, the Cosmotheoros contained an introduction to the Copernican system, a critique of Cartesian cosmology, and the presentation of some new (and revolutionary) astronomical calculations. In addition to these conventional themes, the first book also contained an extensive discussion in support of the possible existence of intelligent life on other planets, followed by the description through a series of 'probable conjectures' of how these planetary inhabitants might look, how they might live, and what they might believe and know. The work opens with a personal introduction that dedicates the work to Huygens's brother Constantijn. Here, Huygens reflects on the hours spent with his brother observing the night sky – and on their dreams of the planets, and their possible natural worlds and inhabitants. The brothers had always ended their speculation with the conclusion that it would be in vain to “enquire after what Nature had been pleased to do there”.1 Huygens then touches upon the historic question for plurality of worlds. He mentions the ancient atomist notion of the infinite universe and the speculations on planetary life of 'Cusanus', 'Brunus', and 'Keplerus', as well as the 'French author' of the 'ingenious dialogues on the Plurality of Worlds'. 2 Huygens qualifies these writings as entertaining speculations that express no ambition to seriously enquire the possibility of habitation of the planets. He also touches upon the 'fairy tales' of Lucian and Kepler. Subsequently, Huygens explains how he has come to the realization that there actually is some room for 'probable conjectures' on the subject. In the second book, after a harsh critique of Athanasius Kircher's anti-Copernican story of a cosmic journey entitled Iter Extaticum, Huygens takes a more astronomical approach to his subject. He now compares the different celestial bodies of the solar system and discusses how the heavens would look from the moon and the different planets. The second book also contains a new and revolutionary method of calculating distances in the universe, that significantly enlarged the conception of the size of the universe, exemplified by a 1 CW, 2. 2 Kosm. 683; CW, 3. 4 calculation of the distance of Sirius.3 The Cosmotheoros concludes with some more contemplative remarks about the infinity of space (Huygens is not sure about the infinity of the universe) and with some critical remarks on Cartesian cosmology. Whereas all his other published material – he did not publish very much – dealt with specialised scientific or technical subjects, this posthumous work was accessible to a larger audience, unskilled in the natural sciences. After Huygens had first written the Cosmotheoros in French, as he mentions in a letter to his brother Constantijn Huygens, he eventually decided to publish it in Latin, not intending to produce a popular work.4 It became his best-seller. Within a few years the book was translated into the English, Dutch, French and German, and in 1717 even a Russian translation was published, ordered personally by Tsar Peter I the Great. The work was repeatedly republished in its different editions and remained popular and was still widely read throughout the eighteenth century. This was not the case with most of his other works, which were often outdated by the rapid developments in the sciences, such as the widespread acceptance of Newtonian physics.5 The popularity of the work is not surprising: not only did the Cosmotheoros provide an accessible introduction to Copernicanism by one of the most famous and authoritative scientists of the period, it was also a good read. The discussion of the lives and habits of the planetarians in particular offers its readers sheer fun, no less today than at its first publication. Although the Cosmotheoros is by far Huygens's most successful work, it plays only a minor role in the biographical and historical scholarship on Huygens's life and work. The reason for this may be that the speculative work is seemingly at odds with the conventional image of Huygens as a stringent mathematician and a pragmatic scientist.