208 The Outline of Science 



A Caution in Regard to Instinct 



In studying the behaviour of animals, which is the only way 

 of getting at their mind, for it is only of our own mind that we 

 have direct knowledge, it is essential to give prominence to the 

 fact that there has been throughout the evolution of living crea- 

 tures a strong tendency to enregister or engrain capacities of 

 doing things effectively. Thus certain abilities come to be in- 

 born ; they are parts of the inheritance, which will express them- 

 selves whenever the appropriate trigger is pulled. The newly 

 born child does not require to learn its breathing movements, as 

 it afterwards requires to learn its walking movements. The 

 ability to go through the breathing movements is inborn, en- 

 grained, enregistered. 



In other words, there are hereditary pre-arrangements of 

 nerve-cells and muscle-cells which come into activity almost as 

 easily as the beating of the heart. In a minute or two the new- 

 born pigling creeps close to its mother and sucks milk. It has 

 not to learn how to do this any more than we have to learn to 

 cough or sneeze. Thus animals have many useful ready-made, or 

 almost ready-made, capacities of doing apparently clever things. 

 In simple cases of these inborn pre-arrangements we speak of 

 reflex actions ; in more complicated cases, of instinctive behaviour. 

 Now the caution is this, that while these inborn capacities usually 

 work well in natural conditions, they sometimes work badly when 

 the ordinary routine is disturbed. We see this when a pigeon 

 continues sitting for many days on an empty nest, or when it 

 fails to retrieve its eggs only two inches away. But it would be 

 a mistake to call the pigeon, because of this, an unutterably stupid 

 bird. We have only to think of the achievements of homing 

 pigeons to know that this cannot be true. We must not judge 

 animals in regard to those kinds of behaviour which have been 

 handed over to instinct, and go badly agee when the normal rou- 

 tine is disturbed. In ninety-nine cases out of a hundred the en- 

 registered instinctive capacities work well, and the advantage of 



