WHAT OF IT? AN OPEN LETTER TO STUDENTS 519 



self to his environment. His development of spoken and written language 

 has made possible the development of a social inheritance which forms a 

 unique addition to his biological inheritance. Through this social inherit- 

 ance the ideas and achievements of past generations are handed on to de- 

 scendants, so that one generation builds upon the achievements of its pred- 

 ecessors in a manner totally unlike anything possible to lower animals. 

 Because one generation does thus build on the achievements of its prede- 

 cessors we have the possibility of social evolution, an evolution independ- 

 ent of biological evolution. The importance of this new evolution cannot be 

 overemphasized. It is a unique achievement of man, and it enables him 

 increasingly to control his own destinies. 



We noted in earlier chapters that biological evolution varies from animal 

 to animal and from time to time. Some animals, hke the cockroach, remain 

 virtually unchanging for vast periods of time while other animals undergo 

 great changes. Still other animals, whose ancestors were highly developed, 

 become simpler in structure, losing many of the ancestral structures — par- 

 ticularly animals which develop parasitic modes of hfe. Evolution, then, 

 does not always mean progress, in the sense in which we usually employ 

 the word, for any particular species (but seep. 499). Yet viewed as a whole 

 the broad trend of evolution has been progressive, producing ever higher 

 types of organisms. Thus progress seems to be part of the design to which I 

 referred earlier. But it is not constant in rate, and it does not involve all 

 forms of life equally. While some forms progress, others retrogress, and 

 others travel down evolutionary blind alleys until they become extinct. At 

 any given time in the earth's history it would be practically impossible for 

 an observer to tell which forms were progressing and which were moving 

 toward extinction. With the wisdom of hindsight we see that in the latter 

 days of the Mesozoic era the dinosaurs were heading for extinction, while 

 the future belonged to the descendants of the insignificant little mammals. 

 But would an observer living at the time have drawn any such conclusion? 

 It seems most unlikely. 



So it is with human evolution. Some human societies remain almost static 

 for centuries, others progress rapidly, still others retrogress. By analogy we 

 may feel confident that some societies will develop into something higher 

 while others, possessing the seeds of their own destruction, will become ex- 

 tinct. But as observers of the current scene we are as little likely to be able 

 to "pick the winner" as would have been our hypothetical observer of the 

 late Mesozoic scene. Thus while we may feel confident that progress will 

 be achieved, we cannot feel confident that it will necessarily be achieved 

 through one particular form of society which we may regard as "best." Per- 



