28 Chapter III. 



live appetite is guided. 1 This peculiarity consists in 

 representing as pleasant to the sentient being what is 

 really useful to it, and simultaneously guiding its 

 physical powers to attain that object. 2 This is the 

 reason why all instinctive activity is unconsciously 

 adaptive. Owing to this peculiarity the formal object of 

 instinctive knowledge seems to transcend the range of 

 sensitive cognition and to contain relations which are not 

 perceptible to the senses. 3 Consequently the scholastics 

 styled it "species insensatse", and called the cognitive 

 power of the animal "the power of appreciation" (vis 

 aestimativa), 4 because it endowed the animal with a 



1 ) Thus we read in tthe Conimbricenses (Commentarii Coll. Con- 

 imbricens, S. J. in 8 libros Physicor. Aristotelis (1592), lib. 2, c. 9, q. 4, 

 a. 2) : Instinctus brutorum nihil aliud est quam operatic phantasiae, de- 

 terminata ad judicium convenientis aut incommodi, dete.rminansque appet- 

 itum ad fugam vel prosecutionem. Haec assertio est philosophorum 

 communis. 



2 ) As far as the use of these powers is not predetermined by innate 

 nerve mechanisms, and only needs actuating by definite sensations. 



3 ) The following example is often used as an illustration: The sheep 

 recognizes in the wolf not only an object of certain color and dimension, 

 but also its natural enemy which it must avoid. This latter relation is 

 the species insensata. On the species insensatae see espec. Suarez, "De 

 anima," I. 3, c. 9, n. 5, 12, 13. 



4 ) Suarez, "De anima," I. 3, c. 30, n. 7: "Aestimativa describitur 

 sensus interior potens apprehendere sub ratione convenientis et discon- 

 venientis . . . haec siquidem operatic communis etiam est omnibus 

 animantibus" (man and brute) . . . "cuius munus est movere appetitum 

 sentitivum, qui non nisi a ratione convenientis vel diseonvenientis 

 movetur. Ideo ergo aestimativa dicitur, quia de rebus ipsis aliud 

 aestimat, quam quod exterius apparet." And Thomas of Aquin had 

 previously observed (Summ. Theol. I. 2, q. 4, a. 2 ad 2) : "Apprehensio 

 sensitiva non attingit ad communem rationem boni, sed ad aliquod bonum 

 particulare, quod est dclectabile. Et ideo secundum appetitum sensiti- 

 vum, qui est in animalibus, operationes quaeruntur propter delecta- 

 tion em." Therefore, what is objectively useful must be represented as 

 subjectively pleasant to the animal by its instinctive power of cognition. 

 This combination of the useful with the pleasant, which is brought about 

 by the suitable disposition of sensitive cognition and appetite, constitutes 

 the real nature of instinct, as we shall at once proceed to demonstrate. 



