EVOLUTION IN GENERAL 279 



But, both in inorganic and organic evolution something is involved 

 — because the processes are different ones. That which is 

 involved in the passage of inorganic nature is tendency to increas- 

 ing randomness, or greater probability of state. That which is 

 involved in organic evolution is what we can only call " anti- 

 randomness," or tendency towards retention of the initial phase 

 of particular cosmic arrangement. Organic evolution expresses 

 this tendency towards something in nature that is improbable 

 in occurrence, all inorganic evolution expressing the tendency 

 toward arrangements of natural things that are indefinitely 

 numerous and therefore highly probable. 



i)ic. Evolution and " Progress." It is not merely 

 humanistic tendency in thought that impels us to regard the main 

 lines of organic evolution as indicating '* progress." We may 

 think of all evolution as leading '' up " towards man, even when 

 we remember the episodial changes that have led to the extinctions 

 and degenerations of many races of organisms. In the 

 evolutionary career the striking thing is the ways in which races 

 of organisms have, on the whole, tended towards ubiquitous dis- 

 tribution, toward complexity of functioning that, more and 

 more, gives them dominance among other kinds of organisms 

 and greater mastery over inorganic nature — that enables them to 

 express more and more opposition to the tendency towards the 

 dissipation of energy that is the characteristic feature of cosmic 

 evolution. It is in this sense that we speak of organic process as 

 a tendency towards progress. 



92. ON HYPOTHESES OF EVOLUTION 



In the chapters on heredity and transformism we have attempted 

 descriptions of the organic evolutionary process as it is understood 

 in current biological thought. 



i, Lamarckian evolution. Organisms, in themselves^ change 

 their modes of activity in response to changes in the environment, 

 or as they migrate into new environments, or as they endeavour 

 all the more to master an approximately constant environment. 

 Successful responses mean that organisms that make them live 

 longer and reproduce more often. The responses are not im- 

 pressions made by the environment on the organisms — they are 

 in themselves organismal changes with tendency. If they are 



