u 



20 Heredity. 



in our own day, attribute to heredity so important a part in the 

 formation of instincts, that they cannot be passed by in silence. 

 Indeed, according to these theories, heredity is one of the essential 

 factors of psychological development ; and so mighty and supreme 

 is its influence, that it not only preserves instincts, but also creates* 

 them. Hence we are obliged to study more closely Jhe nature of 

 instinct, and to abandon the domain of facts, in order to enter into 

 that of causes, that is, of hypotheses. This is to be regretted, for 

 it is no trifling thing to attempt cursorily a theory of instinct. To 

 us it seems that there is not in the whole field of psychology a 

 > more intricate question than this ; and Schelling did not at all 

 exaggerate when he said, 'For the thinker there are no phe- 

 nomena more important than the phenomena of animal instinct, 

 nor is there any better criterion of true philosophy.' 

 / We will restrict our brief inquiry into this subject to two 

 A questions What is instinct ? and, What is its origin ? 



To the first question we reply : Instinct is an unconscious 

 mode of intelligence. To the second : It is possible that instincts 

 are only habits fixed by heredity. > 



It cannot be denied that it is only within the past hundred years 

 that instinct has been seriously studied. The present century 

 especially has done much. In past times we find only confused 

 views and ingenious paradoxes : but naturalists have now removed 

 the question to its proper sphere, that of observation and experi- 

 ment. But when we study instinct from the naturalist's standpoint, 

 the first thing that strikes us is the perfect adaptation of organs to 

 instinct. 'An animal's form corresponds perfectly with its 

 habits ; it desires only what it can attain by means of its organs, 

 and its organs do not incite it to anything for which it has not 

 a propensity. The mole, destined by its needs to live under- 

 ground, has in its organs nothing that would lead it aside from 

 that disposition. Although it can see, still its sight lacks precision, 

 because its eyes are small, and surrounded by a close growth 

 of hairs. Its fore-paws are altogether organized for burrowing, 

 not for walking. The paw is so formed and so related to the 

 fore-arm, that it can hardly be used for locomotion without 

 delving. The sloth, which walks upon the outer edge of the feet 

 with the toes doubled in, is extremely tardy of movement on level 



