218 ANIMAL BEHAVIOUR 



But while there is a hierarchy of activities, the diverse modes 

 often overlap. Just as the surface relief of a countryside 

 may show in one feature the outcrop of various strata of 

 very different geological age, so in an animal's behaviour 

 there is often a mingling of different kinds of activities uni- 

 fied in a way that baffles analysis. Instinct concatenates re- 

 flexes, and intelligence catches up tropisms. Instinctive 

 capacities may form a basis for an advance in intelligence; 

 and intelligently controlled behaviour may sink into habit. 

 We have to distinguish in general (a) the ingrained or en- 

 tailed hereditary capacities of responding effectively to cer- 

 tain stimuli, circumstances, and situations; (6) the indi- 

 vidual tentatives, selections, adjustments, and ' learning ' 

 which seem to many to imply some degree of awareness or 

 pre-awareness and some conative element; and (c) the in- 

 dividual retention and registration of experience which facil- 

 itates for the individual the rapid repetition of effective 

 reactions. 



Our survey suggests some general impressions: (1) The 

 first is a deepening of rational wonder before the extraordi- 

 nary variety of ways in which living creatures express them- 

 selves, assert themselves, enjoy themselves, and bend the 

 Titan of the inorganic to their indomitable endeavour. An 

 unsophisticated but shrewd observer of Nature once said that 

 he could not understand a man intelligently watching an ant- 

 hill and remaining irreligious. 



(2) The second is an impression of the pervasiveness of 

 a kind of behaviour which, considered objectively, is closely 

 analogous to what we know in our case to be associated with 

 intelligent control. The inference, which does not admit 

 of direct verification, is that consciousness in some form is 

 pervasive. We cannot well describe the behaviour of even 



