THE EVOLUTION OF LIFE 



The effort that the great Lamarck made in 1809, 

 in his Philosophie Zoologiqiic, to establish transformism 

 deserves high appreciation from monists, because it was 

 the first attempt to give a natural explanation of the 

 origin of the countless species of organic forms which 

 inhabit our planet. Up to that time it had been the 

 fashion to attribute their origin to a miraculous interven- 

 tion of the Creator. This metaj^hysical creationism had 

 now to face physical evolutionism. Lamarck explained 

 the gradual formation of organic species l)v the inter- 

 action of two physiological functions — adaptation and 

 heredity. Adaptation consists in the imjjrovement oT" 

 organs by use, and degeneration by disuse; heredity 

 acts by transmitting the features thus acquired to 

 posterity. New species arise by physiological transfor- 

 mation from older species. The fact that this great 

 thought was overlooked for half a century docs not 

 detract from its profound significance. But it onlv 

 obtained general recognition when Darwin had supple- 

 mented it and filled up its causal gaps by the theorv of 

 selection in 1859. Apart from this specifically Darwin- 

 ian feature (whether it be true or not), the fundamental 

 idea of transformism is now generally received ; it is ad- 

 mitted to-day even by metaphysicians who maintained a 

 spirited opposition to it thirty years ago. The fact of 

 the progressive modification of species is only intelligible 

 on Lamarck's theory that the actual species are the 

 transformed descendants of older species. In spite of 

 all the learning and zeal with which the theory has been 

 attacked, it has proved irrefutable; nor can any one 

 suggest a better theory to replace it. This may he said 

 particularly of its chief consequence — the descent of man 

 from a series of other mammals (proximately from the 

 apes). 



The high value of Darwin's theory of selection for the 

 monistic biology is now acknowledged by all competent 



