146 DANIEL A. CALLUS 



tatione matris suae, he is assuming an erroneous fact, though 

 it was taught by many physicians in his day.^* 

 In conclusion: 



(i) The immediate and main sources of the problem of the 

 unity or plurality of souls and substances in man are Avicenna 

 and Avicebron. The former stood for the unity thesis in every 

 living being; the latter advocated plurality of forms in all 

 compounds. 



(ii) The problem was formulated by Dominic Gundissalinus, 

 and it reached the schools through him. Under the influence of 

 Avicenna he transmitted the unity thesis in his De anima, but 

 he popularized the opposite view through his other writings 

 drawn chiefly from Avicebron. 



(iii) Various elements of diverse kind mingled with the main 

 sources: the Platonic-Galenic teaching on the tripartite dis- 

 tinction of the soul and on embryo-genesis; the theory of Costa- 

 ben-Luca and of Isaac Israelita on the vital spiritus as distinct 

 from the soul and as a medium of union with the body; the 

 Liber de causis. All these secondary sources contributed to 

 reinforce the pluralist stream. 



(iv) The first reaction of the Schoolmen was in support of 

 the unity thesis, both in the faculty of Arts and in the faculty 

 of Theology. Theologians in general held the thesis of one soul, 

 one substance in man; they held that the vegetative, the sensi- 

 tive and the rational in man are not three souls and three 

 substances, or one soul and three substances, but one soul and 

 one substance. St. Albert the Great voicing their view main- 

 tained that " error pessiinus est dicere unius subiecti plures 

 esse substantias, cmn illae substantiae non possunt esse nisi 

 jormae." ^^ And again: " Hunc errorem hucusque in diem 

 sequuntur quidam Latinorum philosophorum, praecipue in sen- 



^* Cf . Albertus Magnus, De animalibus, XVI, tr. I, c. 2, where he ascribes such 

 a view to some " de medicorum imperito populo "; St. Thomas, Contra gentiles, 

 II, cap. 89. 



"^ De unitate intellectus contra Averroem, cap. 13 (ed. Borgnet, IX, 455 b) . 



