192 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 the philosophy of St. Thomas during the past several 

 decades.^ 



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 paleo- 

 graphical 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) . Theo- 

 doric's contributions to medieval optics and scientific method- 

 ology 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 gen- 

 erally not been recorded.® I shall attempt to fill this lacuna by 

 a resume of the unedited opusculum De elementis corporum 

 naturaliuTn ijiquantum sunt partes mundi,'' 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. 26) , The University Press, Fribourg: Switzer- 

 land, 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. 



' This opusculum was probably written about the year 1300. Two complete manu- 

 script 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 foimd in Cod. Vat. 

 Lat. 1121, henceforth referred to as T. When a reading of the Latin text is given 

 below, it is generally a composite text based on all available manuscripts, as indi- 



