xvi SYSTEMATIC THOUGHT 375 



are formulated evolve. There is indeed one other regulative 

 condition, namely, the stage of intellectual development 

 reached. This has an important influence in more than 

 one shape, as we shall presently see, but it is not the basis 

 of the matter. 



From a very early if not the earliest stages of develop- 

 ment onwards, the maintenance of the species rests on two 

 conditions, conditions often so closely related as to be 

 almost identical, but at times thrown into sharp contrast 

 and antagonism. The first of these is what we may call 

 the principle of self-maintenance, " the will to live." We 

 have observed this principle at work in the processes to 

 which we do not attribute consciousness at all, in the form 

 of that tendency to self-maintenance which we attribute to 

 organisms as such. It persists in the various impulses 

 tending not merely to the maintenance of life, but to the 

 maintenance of the individual in his own character, the 

 fulfilment of his impulses or desires, the realisation of his 

 individuality. But this principle is from an early stage 

 limited and controlled or modified in its action by another. 

 In all but the lowest stages, the life of a species depends 

 not only on the efforts of each individual to main- 

 tain himself, but on a certain unique relation between 

 different individuals composing the species. At least as 

 soon as distinction of sex appears, the individuals of a 

 species begin to have need of one another. They are not 

 complete each in himself, but need a complement, which 

 they find in another individual possessing the same funda- 

 mental specific character developed with certain differences. 

 The most obvious and most permanent need of this kind 

 is that of sex, but in the highest orders this relationship 

 takes a thousand different shapes. The young needs the 

 parent, and so also does the parental instinct cry out for 

 young ones to satisfy it. The gregarious instinct runs far 

 down into the lower animal world, and in human life every 

 man must needs have some other human being by him, if 

 only to annoy him. Even rivalry and hatred rest on some 

 sort of consciousness of a common nature subjected to 

 difference, and of mutual help and love we need not 

 speak. 



