Nature of Evolutionary Progress 57 



do continue. The changes in many of these branches 

 are of a sort that can be called progressive. They 

 lead to a fuller, more varied, more differentiated 

 life. The original organic mass was amoeba-like, 

 without organs of sense; without differentiated 

 organs of any kind, to bring about a correspond- 

 ence between its activities and those of the sur- 

 rounding world. In many of the groups of organ- 

 isms that have branched forth from this original con- 

 dition, organs of various sorts arise. Sense organs of 

 different types come into being, giving fuller correla- 

 tion of the inner life with the outer processes. Many 

 other structures arise which have similar effects. The 

 inner processes — the mental experiences and their 

 correlated behavior — become more and more com- 

 plex, more diverse in kind, more responsive to the 

 different aspects of outside nature. It is very clear 

 that the life of man is fuller, more copiously and 

 adequately correlated with the rest of the processes of 

 nature, richer in its diverse mental experiences, than 

 is the life of a bacterium or an amoeba. There are in 

 the organic world many great series of such degrees 

 of fulness of life and adequacy of correlation with 

 the rest of nature — series leading in many different 

 directions. The existing groups of organisms — in- 

 fusoria, snails, flies, sparrows, mice, cats, men, and 

 hundreds of others — illustrate and exemplify the 

 multifarious results of progression in many different 

 directions. They are the stations which advancing life 

 has reached up to the present time. Some, it is clear, 

 have reached degrees of fulness of life and adequacy 



