ORIGINS OF THE PROBLEM OF UNITY OF FORM 129 



of inquiry and new approaches to old problems. It was through 

 his treatise De anima, together with Avicenna's Liher sextus 

 naturalium, that the question concerning unity of form reached 

 the schools. 



Gundissalinus deals with the question in Chapter IV: Anima 

 an una vel multae, a faithful echo of Avicenna's An sit una an 

 multae. 



Following Avicenna closely, Gundissalinus discusses two dis- 

 tinct questions. The first is whether in all living beings there 

 is one single soul which, though in itself one substance, in virtue 

 of its manifold powers performs the function of vegetative life 

 in plants, of sensation in animals, of intellect and reason in 

 man. Thus, a single rational soul produces, according to its 

 various powers, vegetation alone in the bones, hair and nails, 

 in other parts of the body sensation and movement, and in the 

 brain intellect and reason. Or again, to use a simile, just as 

 one and the same solar ray causes different effects in different 

 things, hardening the clay and melting the wax, so one and the 

 same soul, according to diversity of bodies, operates diversely, 

 bestowing upon some mere existence, upon others sensation, 

 and making others rational beings.^^ 



The other question propounded here is whether in man the 

 vegetative, the sensitive and the rational are three distinct souls 

 and substances, or one soul and one substance only. It is 

 obvious that the former topic is not to be confused with the 

 latter; they are two distinct problems. 



The first opinion, qualified as erroneous, is rejected (hunc er- 

 rorejn ita destruunt philosophi) . Gundissalinus argues against 

 it that these three are in reality not only three powers, but 

 three souls specifically distinct from each other, the vegetative 

 which is in plants alone, the sensitive which is in brute animals, 

 and the rational which is in man. The evidence that they are 

 distinct from each other is that each one possesses a separate 

 existence; hence one cannot be the other. The vegetative is like 



^^ " The Treatise De Anima of Dom'micus Gundissalinus," ed. J. T. Muclde, 

 Mediaeval Studies, II (1940), 44. 



