DEMONSTRATION AND SELF-EVIDENCE 23 



passion to be proven of the scientific subject, we must know 

 only its nominal definition. In fact we cannot, prior to 

 demonstration, know its essential definition, for this is what is 

 to be proved. To know, prior to demonstration, the essential 

 definition of the proper passion in the demonstration, is to 

 know its inherence in its proper subject (i. e., the scientific 

 subject of this demonstration) , for the proper subject is in- 

 cluded in the essential definition of the passion .^^ It would seem 

 that a proposition "per se in the second mode, with a proper 

 passion predicated of its subject, is self-evident in itself, since 

 the subject itself is in the definition of the predicate, but not 

 self-evident to us, precisely because we fail to understand the 

 essential definition of the passion short of demonstration. 

 Cajetan seems to agree with this position, for when he points 

 out that the per se nota proposition whose predicate falls into 

 the definition of its subject is only the principal type of per 

 se nota proposition, he adds a second type in which a passion 

 is said of its proper subject.^® If this type of proposition is self- 

 evident it cannot be self-evident secundum nos, since it can 

 be demonstrated, but in se tantum. Suppose this is the case, 

 why should it be that this is per se nota only in se? The reason 

 may be found in the type of causality exercised by the proper 

 subject in reference to its proper passion. This is at least 

 material causality, and in the case of the second mode of 

 perseity it is precisely material causality which is actually 

 involved." But matter as such is not proportioned to manifest. 

 The connection between the subject and its property is mani- 

 fested to us only by way of the form which is implied by the 

 subject and which is the active cause of this property. The 

 conclusion can be said to be virtually in the fourth mode of 

 perseity because its subject implies this form. It is only in 

 explicating this in the propter quid demonstration that we see 



"" Ibid., lect. 2. 



'' Catejan, In I Post. Anal, Ch. 19. 



" In I Post, Anal., lect, 10, n. 4. 



