DIFFERENTIALS AND EVOLUTION 607 



aims functioned instead of the later, more universal ones. Ultimately there 

 tends to be created a humanistic mode of life, which can develop only at a level 

 of evolution reached by man. At this level, the physical as well as the psychical 

 factors of life attain a balance in which the wellbeing, bodily and mental, of 

 the individual will best be guarded. 



Thus the contradiction between our concept of our personality and what 

 has been considered as the ultimate master of the fate of species and individ- 

 uals, namely, the natural and social struggle, will be diminished as far as the 

 latter are in conflict with the physiological needs and desires of the individual, 

 and only such safeguards will be established in this process as will make possi- 

 ble the avoidance of retrogression and degeneration, bodily as well as mental, 

 in human society, without abandoning the principles and ideals of civilization 

 and their practical application to civilized life. In man, the thought-life pre- 

 dominates and the realization of ideas may give the deepest meaning to his 

 existence ; if the ideas represent true abstractions and generalizations, if they 

 are in harmony with science, they are no longer concerned solely with narrow 

 circles of individuals, but with all humanity, and finally they may comprise the 

 universe; they may then become the possession of mankind. Thus the con- 

 flict between the wishes of the individual and his fate in the natural and 

 social struggle will, in the end, be mitigated and the struggle for the survival 

 of the fittest will be replaced by the knowledge and understanding of a 

 civilized society, in which a conscious direction of further evolution may take 

 place. 



In the course of evolution there have then developed organisms in which 

 individuality and its constancy depend upon three factors: 1) the structure, 

 function and interrelations of organs and tissues; 2) the function in particular 

 of the nervous system especially that on which memory is based and which gives 

 distinctiveness and continuity to the highest organism, man; and 3) the 

 action of organismal and individuality differentials. 



As to the first factor, organs and tissues are in a constant flux from early 

 embryonal life through early extrauterine, to adult life and old age ; there is 

 a greater difference between the structure and function of an embryonal tissue 

 and organ and the corresponding tissue and organ in the same individual 

 during old age than between the organ or tissue characteristics of two different 

 individuals at comparable ages; it is only the potentiality of organs and 

 tissues to undergo a certain development in the same individual which is 

 characteristic of the individual and constant. Regarding the significance of 

 memory in the maintenance of individuality in the psychical sense, the effect 

 of the latter is imperfect and limited in time ; it cannot fully function as the 

 expression of individuality. There remains the third factor, the action of 

 organismal and individuality differentials, which is completely characteristic 

 of the individual and which maintains its identity in the same organism ; this 

 factor then represents the essential individuality, whereas the first two factors 

 merely support this essential individuality; each of these factors has passed 

 through a definite evolution which we have correlated with the evolution of 

 the other factors. 



