HUMAN MENTAL DEVELOPMENT 381 



elaborate impulses as in the lower. Such a being as the caterpillar 

 is able to fend for itself from the first, but just in proportion as 

 animals are intelligent they are helpless at the beginnings of 

 consciousness, and correspondingly capable later. A young pig 

 can run as soon as it is born, but the acquirements of the ' learned ' 

 pig are small compared to those of a dog which is more helpless 

 at birth but so teachable, so capable of learning, that it becomes 

 the companion of man. All our domesticated animals, except such 

 small and harmless types as silk-worms, are teachable, and for that 

 reason we are able to tame them. A tiger or a leopard cannot easily 

 be domesticated because instinct forms too large and memory too 

 small a proportion of its total mentality. Domestication, in the 

 sense meant, implies intelligence, and therefore memory. 



632. Of living beings man is by far the most helpless at birth. 

 He cannot even seek the breast. In him instinct is at its minimum 

 and memory at its maximum. For him, more than for any other 

 animal, is prolonged and elaborate tuition necessary. But, so vast 

 is his memory and so great his power of utilising experience 

 stored in it, of growing mentally under the stimulus of use, 

 that in later life he is beyond comparison the most capable of 

 the inhabitants of the earth. Compare what even a dull man 

 knows, including the words of a language with their inflections 

 and articulations, with what is acquired by the cleverest dog or 

 monkey and the immensity of the difference is at once apparent. 

 We may take a frog and rear him solitary from the egg in an 

 aquarium. If, when he is adult, we remove him to a pond, he will 

 take his place with his fellows at once. He has little if anything 

 to learn. Instinctively he ' knows ' his food and how to seek it, 

 his enemies and how to avoid them, his mate and how to deal with 

 her. But how forlorn and helpless would be a man reared from 

 infancy out of sight and sound of his kind and then turned into a 

 world where his experienced fellows struggled for existence. 



633. Traditional knowledge that is knowledge imparted by 

 one generation to the next is common enough amongst the 

 higher animals and forms no inconsiderable part of their mental 

 equipment. Thus we may see the hen, impelled by an instinct, 

 teaching her chickens, as she herself was taught, to seek food, and 

 the cat teaching her kittens how to ambush mice. The young 

 animals, on the other hand, discover an instinctive interest and 

 pleasure in copying their elders. While insects and others of the 

 lower type learn nothing from the presence of man, birds and 

 mammals learn much. When inhabiting desert islands they have 



