422 NATURE AND NURTURE 



exceptional mathematical ability by means of which he achieves 

 considerable mathematical learning if afforded the opportunity. 

 The ability is * inborn ' and tends to be ' inherited ' by offspring ; 

 the acquirements are not. That is, the child, if he lives and grows 

 at all, is sure to have food and therefore to develop, unless he has 

 varied, the parental capacity ; but he is not sure to have the 

 parental training, the nurture of the same use. Therefore, even if 

 he 'inherits' the parental ability, the child of a great mathe- 

 matician may, or may not, achieve similar distinction. But such 

 a one is more likely than the child of an ignoramus, not only to 

 inherit ability, but to receive the right training. Without the 

 training the ability is naught ; just as without coal the engine is 

 naught. Nutriment, therefore, bestows on the child the parental 

 aptitudes ; association with the parent tends to bestow the 

 parental acquirements. Consequently children tend to resemble 

 their parents for a double reason ; first, because they tend to have 

 much the same capacities, and second, because they make much 

 the same acquirements. We must bear in mind, however, that the 

 parent is not the only influence in the child's environment. 

 Therefore, not only may the child vary from the parent in capacity, 

 but also he may differ in acquirements. 



695. Mathematical efficiency depends on mathematical acquire- 

 ments made by virtue of mathematical capacity and in response 

 to mathematical experience. The efficiency is impossible without 

 the acquirements, and the acquirements without both the capacity 

 and the experience. The same is true of all other intellectual char- 

 acters. But the part played in the creation of efficiency by 

 capacity on the one hand, and by experience on the other by 

 nutriment on the one hand and use on the other varies with 

 different characters and in different species. The caterpillar 

 apparently owes nothing to acquirement ; he has no substratum of 

 capacity wherewith to store experience and therefore cannot 

 utilize it. The acquirements of the cat, for example the increased 

 efficiency in hunting which practice bestows, are, as a rule, nothing 

 more than mere extensions of pre-existing instincts comparable to 

 those extensions of its physical structures which are bestowed by 

 use. Some of man's acquirements are also mere extensions of 

 instincts. Thus, both parental and sexual love tend, within limits, 

 to be increased by association with the objects of affection. 

 Speech is an extension of the infant's tendency to utter useful 

 but inarticulate cries. In this case, however, the extension is im- 

 measurably greater than the thing extended. But unlike extensions 



