Gravitational Motion According to Theodoric of Freiberg

GRAVITATIONAL MOTION ACCORDING TO THEODORIC OF FREIBERG T HE recent appearance of Marshall Clagett's The Science af Mechanics in the Middle Ages 1 has focussed attention once again on the wealth of material made available by scholars in the " Dark Ages " for the development of science as we now know it. Concentrating on " the mechanical doctrines of the medieval period which were framed in mathematical terms or had important consequences for a mathematical mechanics," 2 Clagett reproduces most of the important texts in this area and analyzes them for the conceptual content that contributed to the revolutionary seventeenth-century development. By intent he avoids the study of methodology, nor does he attempt to evaluate the complex relationships that existed between physics and natural philosophy during this period. Yet even these areas have not been without their share of attention in the recent literature. Three significant studies of medieval scientific methodology have appeared in succession,3 and Anneliese Maier has recently concluded the fifth volume of her monumental Studien zur Naturphilosophie der Spatscholastik 4 with some weighty observations on the transitional philosophical concepts that gave rise to the new 1 University of Wisconsin Press: Madison, 1959, xxix + 711 pp. • Ibid., p. xxii. 8 A. C. Crombie's Robert Grosseteste and the Origins of Experimental Science, Oxford, 1953; my own The Scientific Methodology of Theodoric of Freiberg, Fribourg , 1959; and J. A. Weisheipl's The Development of Physical Theory in the Middle Ages, London, 1959. • Zwischen Philosophie und Mechanik, Rome, 1958, particularly pp. 373-382. The five volumes, which we shall henceforth refer to as Studien I, II . . . etc., ~re entitled respectively: I. Die Vorliiufer Galileis im 14. Jahrhundert (1949); II. Zwei Grundprobleme der scholastischen Naturphilosophie (1951); III. An der Grenze von Scholastik und Naturwissenschaft (1952); IV. Metaphysische Hintergmnde der spiitscholastischen. Naturphilosophie (1955); and V. Zwischen Philosophic und Mechanik (1958). 8~7 328 W. A. WALLACE science. All of these works are fruitful sources of study for the Thomistic philosopher of science who would evaluate modern science in light of the traditional concepts of natural philosophy. It is to be hoped that the time will not be long before some penetrating studies in this area may help solve the stubborn problems that have frustrated and divided adherents to th~ philosophy of St. Thomas during the past several decades.5 Meanwhile these works have also signalized the importance of studying manuscript sources to fill the gaps in our knowledge of medieval science. Clagett's work, by his own admission, would have been quite impossible without the prior paleographical efforts of Maier and Moody. It is in a spirit similar to that in which the latter research was undertaken that I should like to offer this brief study of gravitational motion according to Theodoric of Freiberg (c. 1250-c. 1310). Theodoric 's contributions to medieval optics and scientific methodology are sufficiently well known not to require further attention, but by some peculiar oversight the views of the German Dominican on the problem of gravitation have generally not been recorded.6 I shall attempt to fill this lacuna by a resume of the unedited opusculum De elementis corporum naturalium inquantum sunt partes mundi,7 which contains • I have in mind the long-standing debate over a so-called " specific distinction " maintained by some to exist between Thomistic natural philosophy and modern science, which has impeded the study of a host of philosophical problems concerning the nature of matter, gravity, mass, energy, light, the elements, etc., all arising in modern science. • The literature on Theodoric is given in my Scientific Methodology of Theodoric of Freiberg .(Studia Friburgensia, No. !'l6), The University Press, Fribourg: Switzerland , 1959. Miss Maier mentions him in several footnotes throughout her volumes, but otherwise has only a brief treatment of his doctrine on the elements in Studien III, pp. 58-69, without considering the relation of the latter to falling motion. 7 This opusculum was probably written about the. year 1300. Two complete manuscript versions are known: Cod. Maihingen (Fiirstliche Bibl. Schloss Harburg, II, 1 qu. 6), henceforth referred to as M, and Cod. Vat. Lat. 2183, henceforth referred to as U. In addition, some fragments of the opusculum are to be...