NATURE AND NURTURE 53 



and his ancestors have passed their lives. Whether he shut his eyes, 

 throw back his ears, and, straightening his tail, plant his teeth in 

 my leg, or crouch at my feet, with his muscles relaxed, his ears 

 pendent, and his tail trailing on the ground, or, putting his tail 

 between his legs, run away howling, the reason for his conduct is 

 not the pain of the blow, but the importance of escape from the 

 further injury which may follow. The means he adopts are those 

 which have been favorable to this result in the past history of dogs. 



The dog, no doubt, knows, just as we do, that, in the ordinary 

 course of events, the attack is a sign of a disposition to do him 

 farther harm ; and he also knows he may arrest or avert this by 

 doing something, on his own part, to meet it ; but, in case of most 

 organisms, we know only the response and not the consciousness 

 of it. 



The kick is a sign of something which may follow, and the 

 actions which do follow are not the effect of the kick, for they are 

 directed or adjusted, either consciously or unconsciously, to an event 

 of which it is only the forerunner. This is what we mean, or, at 

 least, an essential part of our meaning, when we say the dog is 

 alive, while the stone is not. It is possible that the properties 

 of the stone may be useful to the stone, but these words are mean- 

 ingless to us ; although we do know that the properties of the 

 dog are useful to the dog or to his species. The changes in the 

 stone are the effect of the blow ; while those in the dog are, in 

 some way, the result of the past history of the dog and of his an- 

 cestors ; for, all through this history, violent assaults have been asso- 

 ciated with danger of further violence. This difference is as wide 

 as the difference between life and its absence ; and the inde- 

 pendence of biology as a science is due to its existence. It is what 

 Herbert Spencer means by the statement that life is adjustment, 

 and it is what Aristotle means by teaching that the essence of a 

 living being is not what it is made of nor what it does, but why it 

 does it. 



A living thing is a being which responds to the changes which 

 go on in the world around it; for life consists in the maintenance' 

 of adjustment between the changes which occur in the external 

 order of nature and those which go on in the living body. Life 

 is response to the established order of external nature; and, so 



