ANIMAL AND RATIONAL INTELLIGENCE 179 



territory where may be a desert or an Eden, but 

 where all is unknown. The contrast between Intelli 

 gence and Instinct is in some respects clearly 

 recognised, even though both terms suffer in general 

 usage by lack of exact definition. Biologists would 

 not generally take exception to the statement made 

 by Darwin, that the fewness and the comparative 

 simplicity of the instincts in the higher animals are 

 remarkable in contrast with those of the lower 

 animals. 1 This implies that there is some broad 

 difference commonly recognised, of such importance 

 as to exalt the lower animals w r hen instinct is 

 considered, just as we exalt the higher mammals 

 when intelligence is the test. This broad contrast 

 is one of the most helpful things for guidance here. 

 Instinct is our name for some power not yet scien 

 tifically explained, determining action, inherent in 

 organic life, and appearing quite low in the scale of 

 animate existence. Instinct stands out clearly as a 

 source of action, distinct, on the one hand, from sensi 

 bility, and, on the other, from intelligence. In assigning 

 its proper value to the statement of Darwin just quoted, 

 it seems necessary to admit that instinct makes up 

 so far, in lower orders of life, for lack of intelligence, 

 securing results unattainable by means of the recog 

 nised laws of sensibility, results so surprising to us as 

 intelligent observers, that we are at a loss to account 

 for their occurrence. Such instincts are illustrated 

 in the nest-building of birds ; in care for the young, 

 as in the insertion of eggs in the heart of a bud which 

 may supply nourishment suitable for the young life, 2 

 or in the sunning of the pupae by the common ants of 



1 The Descent of Man, p. 67- 2 See page 186. 



