68 evolution: the ages and tomorrow 



needs and desires started and maintained— a concept of will- 

 ing and desiring and fulfillment. He pointed out that the use 

 of an organ brought about development, and that disuse re- 

 sulted in degeneration. He thought that any modifications 

 produced by needs and uses in the organism during its life- 

 time would be passed on to its offspring with cumulative 

 results over a period of time— the inheritance of acquired 

 organic characters. To Lamarck, the environment acted di- 

 rectly on the organism or through its nervous system; and 

 his whole thesis is and has been a comfort to the environ- 

 mentalists. Endless discussion and experimental study have 

 been applied to the concept of inheritance of acquired 

 organic characters, the critical principle of the whole hy- 

 pothesis, without producing any uncontested positive evi- 

 dence, Lysenko and the Russian school to the contrary not- 

 withstanding. The thesis suffers from the paucity of real 

 evidence, a condition that results from the much more satis- 

 factory and promising way the evolutionary problem can be 

 attacked by the geneticist who sees mutations arising at ran- 

 dom and without any reference to needs and desires. 



In organic evolution, then, the Lamarckian assumption 

 would definitely not seem to apply; but it is possible that in 

 the evolution of man's society, where knowledge and learned 

 activities are important, the transmission of acquired social 

 characters is a factor. The inheritance of learninor is dis- 

 tinctly limited in all animals, except man, to the immediate 

 generation. Higher animals show the beginnings of tradition 

 in that offspring learn from parents, but the transmission 

 never bridges more than one generation. In man, however, 

 what is passed on acquires an independent existence, form- 

 ing a tradition that can be endlessly improved in quality and 

 increased in quantity. Here is a new evolution carried for- 

 ward by language, spoken and written— a supplement to the 

 evolution carried forward by the germinal plasma. 



This evolution by cumulative traditions, as well as the 

 adaptiveness of his hands has given to man his dominant po- 



