BASIS OF THE PKOBLEM 51 



outside the world of perception. Common elements m the 

 perceptual order are recognized and there is thus made possible 

 a grasp of the continuity running through experience. 



Man is thus no longer guided by what is immediately given in 

 experience ; he can make plans and shape his actions with an 

 ideal end in view. With the development of conceptual thought 

 goes the development of language, whereby man learns from^ 

 others and passes on to others what is in his mind. Of the stage 

 of conceptual thought there will be more to say in a later chapter. 

 This further development is only mentioned here in order to 

 contrast mental process in its highest form in man with the 

 process in animals. 



10. We have now to consider the bearing of mental development 

 upon the process of reproduction. All animals are endowed 

 with a certain power of reproduction which we shall call fecundity. 

 Fecundity is measured by the number of ripe ova produced, the 

 number of spermatozoa having no direct bearing on fecundity. 

 We have seen that the highest animals — those most nearly related 

 to man — are gifted with instinct and intelligence. The value of 

 intelligence lies in the fact that it enables instinct to adapt itself 

 to the special circumstances of the moment and thus to bring 

 about its end more surely. The sexual instinct is in this manner 

 assisted by intelligence, and among animals which copulate the 

 power of reproduction is thus able to realize itself to the full or 

 almost to the full. There may be certain failures to achieve 

 reproduction and certain cases of perverted instinct ; to some of 

 these cases we have already referred. Broadly speaking, however, 

 it is true that the highest development in animals of instinct and 

 intelligence works towards the fulfilment of that degree of 

 fecundity which is innately given. It follows, therefore, that in 

 this sense mental development among animals has not in any 

 fashion changed the position of the higher animals when compared 

 with that of the lower animals. Keproduction in the sea-urchin 

 and reproduction among the mammals — vastly as the mental 

 processes differ — is still similar in this respect. The power of 

 reproduction is realized to the full or almost to the full. All that 

 instinct and intelligence do is to ensure that in this more com'' lex 

 process of fertilization the full power of reproduction is as nearly 

 as possible realized — that is to say, that nearly all ova are 

 fertilized. 



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