130 DANIEL A. CALLUS 



the genus to its species; it is therefore in plants as well as in 

 animals; but plants and animals are specifically diversified. 

 Nevertheless, from the fact that each taken separately is speci- 

 fically distinct, it does not follow that they are also distinct 

 subsances when they are united. For instance, a palm tree and 

 a vine are both a tree, that is, they are endowed with vegetative 

 soul, a power of self-nurishment and growth. Yet for a palm or 

 a vine there is not required another soul in addition to the 

 vegetative soul, namely, the soul of a palm or of a vine. It is 

 one and the same soul that makes the living, growing tree a 

 palm or a vine.^" 



Likewise the three vital powers, vegetative, sensitive and ra- 

 tional, exist in man. Taken separately, each one is a substance 

 distinct from the other, but this is not the case when they are 

 jointly existing in man. As the sensitive includes the vegetative 

 and has something else besides, that is, sensitivity, so the 

 human soul is one single substance {cum sit una simjjlex sub- 

 stantia) , implying in itself, not only the rational but also the 

 vegetative and the sensitive, not however as distinct substances 

 {nan tamen tres substantiae sunt in homine) , but simply as dis- 

 tinct powers. Moisture and heat, taken separately, are dif- 

 ferent, but conjoined in vapor they make one single thing,^^ 

 The higher soul presupposes the lower, without which it can- 

 not exist. Neither can the sensitive exist without the vegeta- 

 tive, nor the rational, in its turn, exist without the vegetative 

 and the sensitive. But the lower form, when conjoined with the 

 higher, has not a separate existence, but is implied in the higher, 



" Ibid., pp. 44-45. 



^' " Quamvis autem omnis anima sit substantia et hae tres simul sint in unoquo- 

 que homine, quoniam in homine est anima vegetabilis, et sensibilis, et rationalis, 

 non tamen tres substantiae sunt in homine; humana enim anima, cum sit una 

 simplex substantia, habet vires animae vegetabilis et vires animae sensibilis et 

 vires animae rationalis; similiter et anima sensibilis habet vires animae vegetabilis. 

 Et quamvis hae vires diversae sint inter se, ita ut una earum non praedicetur de 

 altera, quippe cum unaquaeque earum sit species per se, tamen nihil prohibet eas 

 simul haberi ab anima rationali. Quemadmodum, quia invenimus humorem in aere 

 non separatum a calore, non tamen idcirco necesse est ut humorem et calorem qui 

 sunt in aere non habeat aliqua una forma vel aliqua una materia. Sic et de viribus 

 animarum." Ibid., p. 45. 



