Conclusion 



positive character, has almost certainly gained plausibility, like 

 so much else in the biological literature of old age, from human 

 preoccupations. The gerontologist, with the prolongation of 

 human life in mind, is interested in something which is not, as 

 such, of interest to the evolutionary 'demon', and whose evolu- 

 tion is in no sense comparable with the evolution of sight. Sen- 

 escence has no function — it is the subversion of function. On 

 the other hand, as Huxley (1942) suggests, the evolutionary 

 process in man has been transferred in the process of cephaliza- 

 tion from the 'demon' to the operation of conscious intellect. 

 It should now be possible in our thinking to separate human 

 goals from the effects of selection, and to renounce the animistic 

 confusion between them which has influenced the past theore- 

 ticians of old age. The whole conception of 'senescence', in fact, 

 belongs to the field of applied science. It embraces a group of 

 deteriorative effects which we have isolated because they are 

 deteriorative — in other words, because human beings dislike 

 them. Some biological thinkers have reduced themselves to 

 impotence in this field by the cultivation of philosophic doubt 

 whether senescence is an 'entity' at all. Viewed abstractly it is 

 not, any more than disease is an 'entity', but the same biologists 

 will certainly encounter, as they approach their seventieth year, 

 a sequence of changes which will kill them within a limited time. 



Insofar as biology is more than a branch of idle curiosity, its 

 assignment in the study of old age is to devise if possible means 

 of keeping human beings alive in active health for a longer time 

 than would normally be the case — in other words, to prolong 

 individual life. People now rightly look to 'science' to provide 

 the practical realization of perennial human wishes which our 

 ancestors have failed to realize by magic — or at least to investi- 

 gate the prospect of realizing them. Under the influence of the 

 study which is necessary to fulfil such wishes, the character of 

 the wish itself generally changes in the direction of realism, so 

 that most people today would incline to prefer the prospect of 

 longevity, which may be realizable, to a physical immortality 

 which is not, and, pari passu, 'potentielle Unsterblichkeit' is al- 

 ready disappearing from the biological literature. An analogous 

 process can be seen in the psychology of individual growing-up. 



The objective of prolonging human life is one which can bear 



191 



