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Kepler's Philosophy and the New Astronomy

Kepler's Philosophy and the New Astronomy

Rhonda Martens
Copyright Date: 2000
Pages: 216
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  • Book Info
    Kepler's Philosophy and the New Astronomy
    Book Description:

    Johannes Kepler contributed importantly to every field he addressed. He changed the face of astronomy by abandoning principles that had been in place for two millennia, made important discoveries in optics and mathematics, and was an uncommonly good philosopher. Generally, however, Kepler's philosophical ideas have been dismissed as irrelevant and even detrimental to his legacy of scientific accomplishment. Here, Rhonda Martens offers the first extended study of Kepler's philosophical views and shows how those views helped him construct and justify the new astronomy.

    Martens notes that since Kepler became a Copernican before any empirical evidence supported Copernicus over the entrenched Ptolemaic system, his initial reasons for preferring Copernicanism were not telescope observations but rather methodological and metaphysical commitments. Further, she shows that Kepler's metaphysics supported the strikingly modern view of astronomical method that led him to discover the three laws of planetary motion and to wed physics and astronomy--a key development in the scientific revolution.

    By tracing the evolution of Kepler's thought in his astronomical, metaphysical, and epistemological works, Martens explores the complex interplay between changes in his philosophical views and the status of his astronomical discoveries. She shows how Kepler's philosophy paved the way for the discovery of elliptical orbits and provided a defense of physical astronomy's methodological soundness. In doing so, Martens demonstrates how an empirical discipline was inspired and profoundly shaped by philosophical assumptions.

    eISBN: 978-1-4008-3109-8
    Subjects: Astronomy

Table of Contents

  1. Front Matter
    (pp. i-vi)
  2. Table of Contents
    (pp. vii-viii)
  3. Figures and Tables
    (pp. ix-x)
  4. Acknowledgments
    (pp. xi-xii)
  5. Abbreviations of Works Frequently Cited
    (pp. xiii-2)
  6. Introduction
    (pp. 3-9)

    One of the most fertile minds ever, Johannes Kepler (1571–1630) made valuable contributions to every field he addressed. He changed the face of astronomy by abandoning principles that had been in place for some 2,000 years, made important discoveries in optics and mathematics, and even constructed astrological charts renowned for their uncanny accuracy. In addition, he was an uncommonly good philosopher.

    One tends not to hear much about Kepler’s philosophical prowess, probably because he did not actually write a treatise specifically on philosophy; his philosophical views were usually advanced as solutions to problems in other disciplines (theApologia pro...

  7. 1 Kepler’s Life and Times
    (pp. 10-38)

    Kepler’s life was marked by personal misfortune, social instability, and intellectual fertility. He was hounded from all sides by physical illness, political and religious strife, and financial distress. An unrepentant Lutheran, he was threatened by the machinery of the Counter-Reformation; at the same time, he was an unorthodox Lutheran, and so was eventually excluded from Communion in the Lutheran Church. Denied a religious home, Kepler craved a politically stable environment in which to carry out his work, but a refuge was denied to him by the frequent wars that seemed to surround him. In 1621 he lamented this situation and...

  8. 2 The Mysterium cosmographicum and Kepler’s Early Approach to Natural Philosophy
    (pp. 39-56)

    In 1621, looking back over an impressive career, Kepler commented that, “almost every book on astronomy which I have published since that time could be referred to one or another of the important chapters set out in this little book [theMysterium cosmographicum], and would contain either an illustration or a completion of it” (MC, 39;KGWVIII, 9).¹ Because Kepler viewed the Mysterium , his first book, as the genesis ofhis later astronomical works, I begin my discussion ofthe relationship between Kepler’s philosophy and his new astronomy here. TheMysteriumwas written as an extended defense of Copernicus at...

  9. 3 Kepler’s Apologia: An Early Modern Treatise on Realism
    (pp. 57-68)

    TheApologia pro Tychone contra ursum, Kepler’s most epistemologically focused work, was written around 1600 but not published until 1858. Jardine speculates that had it been published in Kepler’s lifetime, and had it received due attention in the interim, it would now “be a classic on a par with such seminal reflections on the nature of human inquiry as theNovum organumand theDiscourse on Method” (Jardine 1984, 5).¹ Instead, like many of Kepler’s works, it has been studied only by a few. What is rather striking about theApologiais that Kepler anticipated and provided sophisticated approaches to...

  10. 4 Kepler’s Archetypes and the Astronomia nova
    (pp. 69-98)

    Theastronomia nova, published in 1609, is probably Kepler’s greatest contribution to astronomy, containing the first articulation of what are known today as Kepler’s first two planetary laws. Having access to Brahe’s data at last, Kepler advanced his “war on Mars.” But, as Stephenson observes, even Brahe’s data was in sufficient to decide between competing theories: “Kepler’s mathematical ingenuity was such that he could invent alternative theories, each good enough to” save “even the excellent observations of Tycho Brahe. These observations, therefore, did not provide enough guidance for him to reach his final solution to the problem of planetary motion”...

  11. 5 The Aristotelian Kepler
    (pp. 99-111)

    Until now my focus has been the positive influence of Kepler’s archetypal cosmology on his epistemology and methodology. Although his cosmology, like his physics, is no longer part of the scientific canon, it retains significance in virtue of its contribution to Kepler’s lasting achievements. To the modern mind, the archetypes are valuable for the roles they played in his astronomical work. But it was his contemporaries that Kepler needed to persuade, not us, and it was his physical astronomy that he needed to defend, not his cosmology. Kepler would have found useful a rhetorical platform from which to justify his...

  12. 6 The Harmonice mundi
    (pp. 112-141)

    Kepler’s imagination was captured in 1599 by the idea that planetary motion could be explained by harmonic theory. He wrote letters to Edward Bruce (who was associated with Galileo), Herwart von Hohenburg, and Michael Maestlin about a harmonic theory that predicted planetary delays better than the nascent physical theory in chapter 20 of theMysterium(KGWXIV 7–16, 21–41, 43–59).¹ He also requested that von Hohenburg send him a copy of Ptolemy’sHarmonics, though he found it to be a frustratingly bad Latin translation. He did not receive theHarmonicsin its original Greek until 1607 (Stephenson...

  13. 7 The Epitome astronomiae Copernicanae: Kepler’s Mature Physical Astronomy
    (pp. 142-168)

    TheEpitome astronomiae Copernicanae, contains much of the material from Kepler’s earlier works, yet stands out in two very important respects. First, it was written for a more general audience, and indeed it gained a relatively wide readership.² Second, Kepler’s mature physics, meta physics, and astronomy were presented together for the first time. As a result, it is an invaluable resource for exploring the evolution of Kepler’s thought, fleshing out his conception of the relationship between physics, metaphysics, and astronomy, and—since theEpitomewas intended as a textbook—uncovering what Kepler believed he needed to do to promote his...

  14. Conclusion The Fate of Kepler’s Philosophical Thought
    (pp. 169-176)

    The archetypes supported Kepler’s realist stance in two ways. They justified his method as truth-linked, and they accounted for the accessibility to the human mind of nature’s underlying structure. In particular, they justified his view that fruitfulness and simplicity are theoretical virtues on the basis of which to adjudicate rival hypotheses. Because God’s essence is simple, and this simplicity is reflected in the material by archetypal correspondence, a theory that does not unify complex phenomena is unlikely to match the archetypes. As God imprinted us with the archetypes, we can rule out hypotheses that “disturbed the mind,” and as the...

  15. Notes
    (pp. 177-190)
  16. Bibliography
    (pp. 191-198)
  17. Index
    (pp. 199-201)