i2 4 MIND IN EVOLUTION CHAP. 



though the field of action is somewhat different we may 

 suppose it to rest on substantially the same psychological 

 and physiological conditions. In both cases it is the 

 satisfaction or dissatisfaction, to use terms derived from 

 our consciousness, the success or frustration of the cona- 

 tion, to use terms which are more objective, which 

 operates to confirm, modify, or inhibit subsequent cona- 

 tion under similar circumstances. 1 



6. The effect of this kind of modifiability is best seen 

 by considering its bearing upon instinct. It acts upon a 

 certain sort of instinctive reaction, and tends, as Mr. Lloyd 

 Morgan has well said, to "define" the instinct. We have 

 seen that an instinct may be congenitally more or less 

 perfect, more or less definite, as the case may be. There 

 is nothing in the general nature of instinct to make it 

 inconceivable that a chick should be born with an inherited 

 tendency, working with certainty and precision from birth, 

 to peck at one sort of caterpillar and avoid another, just as 

 a certain fly passes over other places, and lays its eggs 

 where a horse will lick them, and so get them into its 

 alimentary canal where they are destined to be hatched. 

 But chicks are not born so. They peck at small things 

 indiscriminately at first, and experience cuts them off 

 certain things and concentrates them on others. Just as 

 the fly reacts to one particular very definite object so the 

 chick reacts to the very indefinite object " small thing 

 within reach." Experience circumscribes this object. It 

 excludes from it yellow and black striped caterpillars, bits 

 of orange-peel, and so on, while it promotes green cater- 

 pillars or bits of egg to prominence within the class of 

 objects that remain. What is true of the chick is true in 



1 The above description of the elementary workings of experience must 

 not be taken for an attempt at explanation. How a fleeting experience 

 can have a permanent effect is strictly a metaphysical rather than a 

 psychological question, and beyond saying that there must be something 

 permanent, whether we call it mind or brain, on which successive experi- 

 ences act, metaphysics can, I fear, do little to answer it. It maybe well, 

 however, in view of certain misunderstandings which have arisen, to 

 remind the reader that the "excitements," "feelings," &c., of which I 

 speak have no substantial existence, but are states of the permanent 

 subject, and that when we speak of their " interactions," the " effect of 

 one excitement on another," and so forth, we are merely using a familiar 

 form of speech to describe relations between different states, or the effects 

 of an experience on the permanent susceptibilities of its subject. 



