14 Heredity. 



been found. Still we may, with a contemporary German philo- 

 sopher, define instinct to be 'an act conformed to an end, but 

 without consciousness of that end ; ' * or we may say, with Darwin, 

 that 'an action which we ourselves should require experience to 

 enable us to perform, when performed by an animal, more espe- 

 cially by a very young one, without any experience, and when 

 performed by many individuals in the same way without their 

 knowing for what purpose it is performed, is usually said to be 

 instinctive.' 2 



If, instead of defining instinct, we endeavour to determine its 

 characteristics, not one of which perhaps is absolutely certain and 

 unquestioned, we find a general agreement as to the following : 



Instinct is innate, i.e. anterior to all individual experience. 

 Whereas intelligence is developed slowly by accumulated experi- 

 ences, instinct is perfect from the first The duckling hatched by 

 a hen makes straight for the water ; the squirrel, before it knows 

 anything of winter, lays up a store of nuts. A bird hatched in a 

 cage will, when given its freedom, build for itself a nest like that 

 of its parents, out of the same materials, and of the same shape. 



Intelligence gropes about, tries this way and that, misses its 

 object, commits mistakes and corrects them : instinct advances with 

 a mechanical certainty. Hence comes its unconscious character ; 

 it knows nothing either of ends, or of the means of attaining 

 them ; it implies no comparison, judgment, or choice. All seems 

 directed by thought, without ever arriving at thought ; and if this 

 phenomenon appear strange, it must be observed that analogous 

 states occur in ourselves. All that we do from habit walking, 

 writing, or practising a mechanical art, for instance all these, and 

 many other very complex acts, are performed without consciousness. 



Instinct appears stationary. It does not, like intelligence, seem 

 to grow and decay, to gain and to lose. It does not improve. If 

 it does not remain perfectly invariable, at least it varies only within 

 very narrow limits; and though this question has been warmly 

 debated in our day, and is yet unsettled, we may yet say that in 

 instinct immutability is the law, variation the exception. 



1 Hartmann, Philosophie des Unbewussten, p. 54. Berlin, 1869. 

 8 Darwin, Origin of Species, p. 255. Fifih Edition, 1869. 



