What is Intelligence, and What is Instinct? 83 



stinctive; for intelligence and consciousness of the end. 1 

 are identical realities. 



We are not allowed to attribute to animals higher 

 psychic faculties than their actions manifest. This in- 

 contestable principle of scientific psychology not only 

 entitles but forces us to regard only those spontaneous 

 actions of animals as intelligent in which consciousness 

 of the end, the power of formal reasoning and of mental 

 abstraction manifest themselves clearly and without a 

 shadow of doubt. All other actions, however, which 

 can be fully explained by the laws of combined sense 

 perceptions must be counted as instinctive, and not as 

 intelligent. There is no possible intermediate member. 



The foregoing deductions lead to the only legitimate 

 conclusion which can be maintained in a critical estimate 

 of the psychic life of animals. All those psychic ac- 

 tions of animals are instinctive that spring from their 

 sensitive powers of perception and appetite, and for the 

 adequate explanation of which it is not necessary to 

 appeal to intelligence in its full and proper signification. 



Whilst instinctive, in contradistinction to intelligent 

 actions, have the essential characteristic of not emanat- 

 ing from individual deliberation, and consciousness of 



x ) By consciousness of the end we understand the perception of the 

 final relation, which Thomas of Aquin (''Summ. Theol." I. 2, q. 6, a. 2) 

 appropriately describes: "Perfecta quidem finis cognitio est, quando non 

 solum apprehenditur res, quae est finis, sed eiam cognoscitur ratio finis 

 et proportio eius, quod ordinatur ad finem ipsum." The formal con- 

 sciousness of the end which we called the essence of intelligence is not 

 identical with adequate consciousness of the end, which comprehends the 

 knowledge of all the ends which can possibly be attached to a certain 

 action; for, in order to have a formal (real) consciousness of the end, it 

 suffices, that any one purpose of the action be perceived and aimed at. 



