THE PHANTOMS BEHIND US 
its exceptional men, its men of genius and power, 
and these have often been like sports or the sudden 
result of mutations — a man like Lincoln springing 
from the humblest parentage. No such extreme 
variations are seen in any of the lower orders. In- 
deed, in one’s lifetime one sees but very slight varia- 
tion in any of the wild or domestic creatures, less 
in the wild than in the domestic because they are 
less under the influence of that most variable of ani- 
mals, man. And man’s variations are mainly men- 
tal and not physical. The higher we go in the scale 
of powers, the greater the variation and hence the 
more rapid the evolution. Probably man’s body has 
not changed radically in vast cycles of time, but 
his mind has developed enormously since the dawn 
of history. 
IV 
Biologists are coming more and more to recognize 
some unknown factor in evolution, probably some 
unknowable factor. The four factors of Osborn — 
heredity, ontogeny, environment, selection — play 
upon and modify endlessly the new form when it is 
started, but what about the original start? Whence 
comes this inborn momentum, this evolutionary 
send-off? What or who set the whole grand process 
going? 
Bergson sees an internal psychological principle 
of development, hence the name of his book, “‘Crea- 
tive Evolution.” Osborn uses the word “directed.” 
Q17 
