CELESTIAL MOVERS IN MEDIEVAL PHYSICS 185 



is no demonstrative reason why they cannot be more numerous, 

 as Catholic theology teaches .^^ Second, he erred by considering 

 some to be substantially united to celestial bodies as their soul; 

 such a union is unreasonable and contrary to Catholic teach- 

 ing.^* Finally, Aristotle erred in considering angels and the 

 universe to have existed from all eternity; such eternity cannot 

 be demonstrated by reason. ^^ St. Thomas himself never doubted 

 that Plato and Aristotle admitted another mode of " coming- 

 into-being " besides physical generation for immaterial sub- 

 stances and the universe. " Over and above the mode of be- 

 coming by which something comes to be through change or 

 motion, there must be a mode of becoming or origin of things, 

 without any mutation or motion through the influx of being 

 {'per iiifluentiam essendi) ." ^^ St. Thomas goes on to say that, 

 although Plato and Aristotle did posit that immaterial sub- 

 stances and even heavenly bodies always existed, " we must 

 not suppose on that account that they denied to them a cause 

 of their being." ^^ On this point they did not depart from the 

 position of the Catholic faith. 



We can now return to St. Thomas' reply to the official ques- 

 tionnaire. His reply to the first three questions simply states 

 that God normally rules His creation through intermediaries, 

 the lower and more gross bodies being ruled by the higher and 

 more subtle. The divine power, however, is in no way limited 

 to the order it has established. Assuming that angels are the 



°^ Ibid., c. 2, nn. 12-13; cf. Sum. contra gent., 11, c. 92. 



^* Ibid., c. 18, nn. 100-101; cf. De spirit, creat., a. 5; Sum. contra gent., 11, c. 

 91; SuTn. theol., I, q. 51, a. 1; De pot., q. 6, a. 6. 



^^ Ibid., c. 2, n. 14; cf. Sum. theol., I, q. 46, a. 1; Sum. contra gent., II, cc. 31-38; 

 De pot., q. 3, a. 17; De aetemitate mundi. 



** Ibid., c. 9, n. 49. 



*^ Ibid., n. 52. For this reason St. Thomas frequently insists that those who 

 interpret Aristotle's God as a mere physical mover or a mere final cause are in 

 complete error. For St. Thomas Aristotle's God is a causa essendi ipsi mundo, a 

 causa quantum ad suum esse, a factor caelestium carporum. " Ex hoc autem 

 apparet manifeste falsitas opinionis illorum, qui posuerunt Aristotelem sensisse, 

 quod Deus non sit causa substantiae caeli, sed solum motus eius." In VI Metaph., 

 lect. 1, n. 1164. Also In VIII Phys., lect. 3, n. 6; In I De caelo, lect. 8, n. 14; 

 In II Metaph., lect. 2, n. 295. 



