SOCIAL EVOLUTION 83 



must become adapted. " Two canine animals in a time of dearth," he 

 remarks, " may truly be said to struggle with each other which shall get 

 food and live. But a plant on the edge of a desert is said to struggle 

 for life against the drought, though more properly it should be said to 

 be dependent on the moisture." 8 Also, "climate plays an important 

 part in determining the average numbers of a species, and periodical 

 seasons of extreme cold or drought seem to be the most effective of all 

 checks." 9 Yet further, " when we reach the Arctic regions, or snow 

 capped summits, or absolute deserts, the struggle for life is almost ex- 

 clusively with the elements." 10 Again, Mr. Darwin often means, not 

 a struggle for food or against the elements, but a struggle to avoid being 

 converted into food. " Very frequently," he writes, " it is not the ob- 

 taining of food, but the serving as prey to other animals, which de- 

 termines the average numbers of a species." 11 And some of his most 

 fascinating pages deal with the variations, such as protective markings, 

 colorings and habits, which are helpful in the mere struggle for safety. 

 Once more, in those paragraphs in "The Descent of Man" already 

 referred to, in which Mr. Darwin recognizes the utility of group soli- 

 darity, he, by implication, takes account of a struggle on the part of 

 associating individuals to adjust their interests and their activities to 

 one another in such wise that group life may be maintained. 



If, then, it is legitimate to use the term, " struggle for existence," 

 " in a large and metaphorical sense," as Mr. Darwin says his prac- 

 tise is, 12 the struggle itself obviously consists of four distinct and 

 specific struggles, namely: (1) the struggle for safety; (2) the struggle 

 for subsistence; (3) the struggle for adaptation by every organism to 

 the objective conditions of its life, and, (4) the struggle for adjustment, 

 by group-living individuals to one another. 



And this large use of the term is legitimate in fact. Mr. Darwin's 

 only mistake was in calling it " metaphorical." For, as Karl Pearson 

 has pointed out, " the true measure of natural selection is a selective 

 death rate," 13 and any circumstance, whether it be danger, or scarcity 

 of food, or non-adaptation to physical conditions, or mal-adjustment of 

 associating individuals to one another, which affects the selective death 

 rate, is a factor in the struggle for existence. 



If so much be granted, a number of difficult questions get a real 

 illumination. What are the true relations of esthetic and economic, 

 of ethical and social phenomena to one another, and to life in its wide 

 inclusiveness ? What, especially, is the precise point of departure of 



8 " The Origin of Species," p. 78. 



9 Ibid., p. 84. 



10 Ibid., p. 85. 



11 Ibid., p. 84. 



12 Ibid., p. 78. 



13 Essay on " Reproductive Selection " in " The Chances of Death and Other 

 Studies in Evolution," Vol. I., p. 63. 



