588 INTERRELATIONSHIPS OF ORGANISMS 



qualities he has in common with the group in question. Conversely, such 

 a recognition of kinship does not imply the occurrence of peculiarly 

 human qualities in nonhuman kin. 



This organic kinship and subjection to biological law are far more 

 obvious in some of man's roles than in others. The acceptance of kinship 

 is implied and unchallenged in all of our concepts of man as a functioning 

 machine. Here our considerable modern knowledge of both function and 

 malfunction largely ignores the boundary between man and other mam- 

 mals and could not have been gained were not the results of animal ex- 

 perimentation applicable to man. 



When we turn to the human individual as a link in a sequence of gen- 

 erations or as the product of evolution, it is somewhat less obvious that 

 he is subject to the same biological principles that apply to other or- 

 ganisms. Here we must often deal with less concrete and immediate 

 evidence. There is not nearly so much room for difference of opinion 

 about the structure of a heart or a brain or about the chemical identity 

 of two well-analyzed physiological reactions as there is about the chain 

 of cause and effect that connects an individual genotype and its pheno- 

 typic expression or the conclusion that the pineal body of the mammalian 

 brain is a heritage from a Carboniferous reptilian ancestor. Some aspects 

 of kinship remain obvious even in the sequence of generations; the proc- 

 esses of germ cell formation, fertilization, and embryonic development 

 can be directly observed and show the same unmistakable relationships 

 that are exhibited by man as a functioning machine. 



Beyond this point, however, we encounter viewpoints and interpreta- 

 tions of data that, based on the purely human phases of man's activities, 

 are less concerned with his biological background. Anthropology, psy- 

 chology, sociology, economics, and the interwoven fields of study we term 

 the humanities are each concerned with peculiarly human aspects of 

 man's activities and relationships. Each of these disciplines has collected 

 and organized the data pertinent to its particular field and has built its 

 own concepts and interpretations of man and his potentialities. When man 

 is studied from these special viewpoints, his organic heritage and con- 

 stitution are obscured by his cultural characteristics and attainments, and 

 the assumption is often tacitly made that man, having become human, is 

 somehow freed from the consequences of any former kinship. 



Much of this ignoring of man's organic heritage comes from the com- 

 plex interweaving of biological and cultural elements in all human ac- 

 tivities and environments and much from the very specialization of study 

 and viewpoint that makes increase of knowledge possible. Our proneness 

 to extend analogies and implications far beyond the factual foundation 

 on which they are based can result in useful hypotheses ; it can also gloss 

 over fatal inconsistencies in a supposed chain of cause and effect if un- 



