16 INTRODUCTION. 



directed towards the accomplishing of adaptive movement, 

 antecedent to individual experience, without necessary 

 knowledge of the relation between the means employed 

 and the ends attained, but similarly performed under the 

 same appropriate circumstances by all the individuals of 

 the same species. Now in every one of these respects, 

 with the exception of containing a mental constituent and 

 in being concerned in adaptive action, instinct differs from 

 reason. For reason, besides involving a mental con- 

 stituent, and besides being concerned in adaptive action, 

 is always subsequent to individual experience, never acts 

 but upon a definite and often laboriously acquired know- 

 ledge of the relation between means and ends, and is very 

 far from being always similarly performed under the same 

 appropriate circumstances by all the individuals of the 

 same species. 



Thus the distinction between instinct and reason is 

 both more definite and more manifold than is that between 

 instinct and reflex action. Nevertheless, in particular 

 cases there is as much difficulty in classifying certain 

 actions as instinctive or rational, as there is in cases where 

 the question lies between instinct and reflex action. And 

 the explanation of this is, as already observed, that instinct 

 passes into reason by imperceptible degrees; so that 

 actions in the main instinctive are very commonly 

 tempered with what Pierre Huber calls ' a little dose of 

 judgment or reason,' and vice versa. But here, again, the 

 difficulty which attaches to the classification of particular 

 actions has no, reference to the validity of the distinctions 

 between the two classes of actions ; these are definite and 

 precise, whatever difficulty there may be in applying them 

 to particular cases. 



Another point of difference between instinct and 

 reason may be noticed which, although not of invariable, 

 is of very general applicability. It will have been 

 observed, from what has already been said, that the 

 essential respect in which instinct differs from reason con- 

 sists in the amount of conscious deliberation which the 

 two processes respectively involve. Instinctive actions are 

 actions which, owing to their frequent repetition, become 



