262 THE PRINCIPLES OF HEREDITY 



I find it difficult to imagine the existence of pleasure or pain 

 without the presence of a corresponding desire to do or not 

 to do. If no desire is present, then the pleasure and pain 

 are useless epiphenomena, the existence of which the known 

 parsimony of nature should cause us to deny. But, if 

 pleasure or pain are absent, then the instincts of lower 

 animals differ so much from our own that they should not 

 be included under a common designation. Moreover, in that 

 case, our instincts hunger, sexual and parental love, and so 

 forth cannot have been derived from the instincts, so called, 

 of our remote ancestors. l If, on the other hand, it be main- 

 tained that desire is not present during the first performance 

 of the instinctive act, but only during subsequent perform- 

 ances of the same act, then the desire is due to the memory 

 of the pleasure or pain, and is once more a useless epiphe- 

 nomenon, since the perfect performance of the instinctive act 

 was possible without it. In that case such an animal as 

 sitaris, which performs a series of instinctive acts only once, 

 is an automaton burdened with an unnecessary memory ; a 

 hypothesis which involves the further hypothesis that 

 memory, which appears always to be correlated with a 

 relatively large amount of nervous tissue, was, with the 



1 Descartes held that the lower animals are pure automata without 

 feelings, desires, fears, hopes, passions, thoughts. Modern authors, 

 however, generally admit the presence of pleasure or pain and desire as 

 essential factors of instinct. " If we analyze the propensity of storing 

 we find it consists of three impulses. First, an impulse to pick up the 

 nutritious object, due to perception ; second, an impulse to carry it off 

 into the dwelling-place, due to the idea of this latter ; third, an impulse 

 to lay it down there, due to the sight of the place. It lies in the nature 

 of the hamster that it should never see a full ear of corn without feeling 

 a desire to strip it ; it lies in its nature to feel, as soon as its cheek 

 pouches are filled, an irresistible desire to hurry to its home ; and 

 finally it lies in its nature that the sight of the store-house should 

 awaken the impulse to empty its cheeks." (Schneider, Der Thierische 

 Wille, p. 208. Quoted by James.) 



" And so, probably, does each animal feel about the particular things 

 that it tends to do in the presence of particular objects. They, too, are 

 a priori syntheses. To the lion it is the lioness that is made to be 

 loved ; to the bear, the she-bear. To the broody hen the notion would 

 probably seem monstrous that there should be a creature in the world 

 to whom a nestful of eggs was not the utterly fascinating and precious 

 and never-to-be-too-much-sat-upon object which it is to her." (James, 

 Principles of Psychology , vol. ii., p. 387.) 



"What voluptuous thrill may not shake a fly, when at last she 

 discovers the one particular leaf, or carrion, or bit of dung that out of 

 all the world can stimulate her ovipositor to its discharge ! Does not 

 the discharge then seem to her the only fitting thing ? And need she 

 care or know anything about the future maggot and its food ? " (Op. 

 cit., p. 388.) 



