184 JAMES A. WEISHEIPL 



then all orders between God and man would be called ' angels ' 

 by Catholics. 



The fundamental weakness of Plato's position, as St. Thomas 

 sees it, is that it is without proof, for his separated intelligences 

 are merely postulated, not demonstrated. " That is why Aris- 

 totle proceeded by a more manifest and surer way, namely, by 

 way of motion, to investigate substances that are separate from 

 matter." St. Thomas' interpretation of Aristotle is substanti- 

 ally that of St. Albert and Kilwardby. Since all generable and 

 celestial bodies are moved, they must be moved ultimately 

 by a substance which is not material. The immaterial soul con- 

 joined to celestial bodies is moved concomitantly with the 

 body, therefore it is moved by knowledge and desire of abso- 

 lutely separated intelligences. " Therefore each of the heavenly 

 bodies is animated by its own soul and each has its own sepa- 

 rate appetible object which is the proper end of its motion." 

 For Aristotle, then, there are as many intelligences as there 

 are celestial souls, and as many celestial souls as there are 

 motions. It was Avicenna, according to St. Thomas, who er- 

 roneously limited the number of separated intelligences to ten, 

 thinking that the multiple motions of a planet could be " or- 

 dered to the motion of one star." In any case, according to the 

 position of Aristotle, between man and God " there exists only 

 a two-fold order of intellectual substances, namely the sepa- 

 rated substances which are the ends of the heavenly motions, 

 and the souls of the spheres, which move through appetite and 

 desire." ^^ Aristotle and Plato both agree that all immaterial 

 substances have their entire being from God, that they are 

 entirely immaterial, and that they are ruled by divine provi- 

 dence. They differ, however, with respect to the number and 

 precise character of separated substances as well as to their 

 relevance to the physical order. 



For St. Thomas the theologian, Aristotle made three serious 

 errors concerning angels. First, he erroneously limited their 

 number to what could be ascertained by celestial motion; there 



t2 



Ibid., c. 2, n. 10; cf. In II De caelo, lect. 18, n. 16. 



