INSTINCT. 389 



from the fact that many bii'ds, e.g. wild ducks, steal eggs from each 

 other. . . . The bodily disposition to sit is, it is true, one condi- 

 tion [since broody hens will sit where there are no eggs], but rhe 

 perception of the eggs is the other condition of the activity of 

 the incubating impulse. The propensity of the cuckoo and of the 

 cow-bird to lay their eggs in the nests of other species must also be 

 interpreted as a pure perception-impulse. These birds have no bodily 

 disposition to become broody, and there is therefore in them no connec 

 tion between the perception of an egg and the impulse to sit upon it. 

 Eggs ripen, however, in their oviducts, and the body tends to get rid of 

 them. And since the two birds just named do not drop their eggs any- 

 where on the ground, but in nests, which are the only places where they 

 may preserve the species, it might easily appear that such preservation 

 of the species was what they had in view, and that they acted with full 

 consciousness of the purpose. But this is not so. . . . The cuckoo is 

 simply excited by the perception of quite determinate sorts of nest, 

 which already contain eggs, to drop her own into them, and throw the 

 others out, because this perception is a direct stimulus to these acts. 

 It is impossible that she should have any notion of the other bird com- 

 ing and sitting on her egg." * 



INSTINCTS NOT AIj"WAYS BLIND OR INVARIABLE. 



Kemember that notliing is said yet of the origin of in- 

 stincts, but only of the constitution of those that exist fully 

 formed. How stands it with the instincts of mankind ? 



Nothing is commoner than the remark that Man differs 

 from lower creatures by the almost total absence of instincts, 

 and the assumption of their work in him by ' reason.' A 

 fruitless discussion might be waged on this point by two 

 theorizers who were careful not to define their terms. 

 *Eeason' might be used, as it often has been, since Kaut, 

 not as the mere power of 'inferring,' but also as a name for 

 the fendency to cbey impulses of a certain lofty sort, such as 

 duty, or universal ends. And ' instinct ' might have its sig- 

 nificance so broadened as to cover all impulses whatever, 

 even the impulse to act from the idea of a distant fact, as 

 well as the impulse to act from a present sensation. Were 

 the word instinct used in this broad way, it would of course 

 be impossible to restrict it, as we began by doing, to actions 

 done with no prevision of an end. We must of course 

 avoid a quarrel about words, and the facts of the case are 



* Der Thierische Wille, pp. 282-3. 



