WHAT IT IS AND WHAT IT IS NOT. 



57 



turning, is the movement of all life. The changes in 

 human history are only typical of the changes that take 

 place in all living creatures. In fact, human history is 

 only a part of one great life current, the movement of 

 which is everywhere governed by the same laws, depends 

 on the same forces, and brings about like results. 



The facts and generalizations of change constitute 

 the subject matter of evolution ; and as the fact of life 

 is a fundamental one and in some degree modifies all 

 phenomena which it concerns, we have as the central 

 axis of the science in question the study of organic evo- 

 lution. In fact, while inorganic evolution or orderly 

 change in environment also exists, we do not know to 

 what degree the laws and forces of organic evolution 

 can be reduced to the same terms of expression. The 

 theory of the essential and necessary unity of life and 

 non-life, of mind and matter, is still a matter of phil- 

 osophical speculation only. We can neither prove the 

 truth of Monism nor understand it ; nor is the contrary 

 hypothesis either comprehensible or credible. The 

 fundamental unity of organic evolution and inorganic 

 evolution is likewise yet to be proved, while the laws 

 which govern living matter are certainly in part peculiar 

 to life. For this reason the evolution of astronomy, of 

 dynamic geology, of geography, as well as the purely 

 hypothetical evolution of chemistry, must be separated 

 from life evolution. Cosmic evolution and organic evo- 

 lution show or seem to show some divergence from each 

 other. To regard them as identical is to introduce con- 

 fusion and not order into our conception of evolution. 

 There are some elements which are not held in com- 

 mon, or which at least are not identical when measured 

 in human terms. It is not evident that any force in 

 the evolution of life is homologous with any which has 

 brought about the evolution of stars and planets. This 



