The metaphysical commitment to the circle as the essential element in the analysis of celestial motion has long been recognized as the hallmark of classical astronomy. What has not always been clear, however, is that the circle continued to serve Kepler as a central element in his astronomy after the discovery of the elliptical orbit of Mars. Moreover, the circle also functioned for Kepler in geometry to select the basic polygons, in music to select the basic harmonies, and in astrology (...) to select the basic aspects. His basic set of polygons consisted of those figures that could be constructed using only a compass and a rule; the set of fundamental harmonies consisted of the consonances of the just intonation; and the traditional set of astrological aspects were enlarged by Kepler to include three new aspects in order to make the astrological set consistent with geometry and music. And as the circle served to unify these three areas, so also did it serve to supply the fundamental answers to astronomical problems well after the discovery of his new astronomy—a topic to be discussed in Part II of this paper. (shrink)

CHAPTER I INTRODUCTION (A) Historical Problem Suggested by the Nature of Modern Thought How curious, after all, is the way in which we moderns think about ...

The question whether Nicholas of Cusa had any influence on Schelling at all, is usually debated with regard to Giordano Bruno. The paper shows that there is also another possible trait of reception. We will find strong evidence that Johannes Kepler intermediates between both philosophers. Therefore five modi cogitandi are systematically analyzed as points of convergence between Cusa and Schelling: 1. docta ignorantia, 2. coincidentia oppositorum, 3. visio intellectualis, 4. coniectura, 5. the literary form of a ›philosophy of mysteries‹.

: We question the claim, common since Duhem, that sixteenth century astronomy, and especially the Wittenberg interpretation of Copernicus, was instrumentalistic rather than realistic. We identify a previously unrecognized Wittenberg astronomer, Edo Hildericus (Hilderich von Varel), who presents a detailed exposition of Copernicus's cosmology that is incompatible with instrumentalism. Quotations from other sixteenth century astronomers show that knowledge of the real configuration of the heavens was unattainable practically, rather than in principle. Astronomy was limited to quia demonstrations, although demonstration propter (...) quid remained the ideal. We suggest that Osiander's notorious preface to Copernicus expresses these sixteenth century commonplaces rather than twentieth century instrumentalism, and that neither `realism', nor `instrumentalism', in their modern meanings, apply to sixteenth century astronomy. (shrink)