INTRODUCTION. 13 



rational, does this exclusively in the sphere of subjec- 

 tivity ; the nervous processes engaged are throughout the 

 same in kind, and differ only in the relative degrees of 

 their complexity. Therefore, as the dawn of consciousness 

 or the rise of the mind-element is gradual and undefined, 

 both in the animal kingdom and in the growing child, it 

 is but necessary that in the early morning, as it were, of 

 consciousness any distinction between the mental and the 

 non-mental should be obscure, and generally impossible to 

 determine. Thus, for instance, a child at birth does not 

 close its eyes upon the near approach of a threatening 

 body, and it only learns to do so by degrees as the result 

 of experience ; at firs L , therefore, the action of closing the 

 eyelids in order to protect the eyes may be said to be 

 instinctive, in that it involves the mind-element : l yet it 

 afterwards becomes a reflex which asserts itself even in 

 opposition to the will. And, conversely, sucking in a 

 new-born child, or a child in utero, is, in accordance with 

 my definition, a reflex action ; yet in later life, when con- 

 sciousness becomes more developed and the child seeks the 

 breast, sucking may properly be called an instinctive 

 action. Therefore it is that, as in the ascending scale 

 of objective complexity the mind-element arises and 

 advances gradually, many particular cases which occupy 

 the undefined boundary between reflex action and instinct 

 cannot be assigned with confidence either to the one region 

 or to the other. 



We see then the point, and the only point, wherein 

 instinct can be consistently separated from reflex action ; 

 viz., in presenting a mental constituent. Next we must 

 consider wherein instinct may be separated from reason. 

 And for this purpose we may best begin by considering 

 what we mean by reason. 



The term ' reason ' is used in significations almost as 

 various as those which are applied to ' instinct.' Some- 



1 I.e., ancestral as well as individual. If the race had not always 

 had occasion to close the eyelids to protect the eyes, it is certain that 

 the young child would not so quickly learn to do so in virtue of its 

 own individual experience alone ; and as the action cannot be attri- 

 buted to any process of conscious inference, it is not rational ; but wo 

 have seen that it is not originally reflex ; therefore it is instinctive. 



