430 MIND IN EVOLUTION CHAP. 



by natural selection. We must only bear in mind, first, 

 that it is the life of the race which natural selection has 

 metaphorically in view. There is to the biologist no 

 paradox in the pleasurableness of self-sacrificing effort on 

 behalf of children, descendants, or even the species as a 

 whole. Secondly, as life becomes more complex, we 

 must remember that what is pleasurable from one point 

 of view may be overwhelmingly painful from another. 

 This understood, we may say that in the first stage of 

 intelligence pleasure and pain are substituted as " masters" 

 of conduct for life and death. The first result is that 

 readjustments which natural selection might take an epoch 

 to effect, are carried through by the direct method within a 

 single lifetime, and perhaps ultimately through a single 

 experience. The readjustment, besides being swifter, is 

 obviously less wasteful of life ; and lastly, it favours an 

 improvement of type. This it does in two ways. From 

 the first, it makes possible a pliability of nerve-structure 

 which, while incompatible with detailed instinct, forms a 

 basis for more various and therefore broader development. 

 If width of scope is one test of development, we see here 

 the beginnings of an upward movement. Secondly, since 

 pleasure and pain instead of life and death are now the 

 determining factors, we see a possibility that modes of 

 action may be built up not concerned with the mere 

 maintenance of the species, but with anything that may 

 yield pleasure to its members. The primitive pleasures 

 and pains will doubtless be connected with race maintenance 

 (as the pleasures of eating, drinking, and sex), and as we 

 have seen both feelings must throughout development be 

 limited in the main by natural selection. This however 

 is a limiting condition only. Pleasures must not be 

 preponderantly unhealthy. It does not follow that 

 pleasures may not arise that have no bearing one way or 

 other on the life of the species. And if experience lights 

 on unexpected sources of pleasure, it will certainly attend, 

 to them, and work them for what they are worth. 

 Further, since we find pleasure in the full development of 

 faculty, it is a possible and indeed a probable case that 

 among the pleasures on which experience lights should be 



