70 FOOT-NOTES TO EVOLUTION. 
from generation to generation never occur. We do not 
expect to find birds arising from a “ flying-fish in the 
air, whose scales are disparting into feathers.” A flying- 
fish is no more of the nature of a bird than any other fish 
is. A cow will never give birth to a horse, nor a horse 
to acow. The slow operation of existing causes is the 
central fact of organic evolution, as it is of the evolu- 
tion of mountains and valleys. Seasons change as the 
relations which produce them change. But midsummer 
never gives way to midwinter in an instant. Nor does 
the child in an instant become a man, though in some 
periods of growth epoch-marking causes may make de- 
velopment more rapid. Life is conservative. The law 
of heredity is the expression of its conservatism. Life 
changes slowly, but it must constantly change, and all 
change is by necessity divergence. 
There is in Nature no single “law of progress,” nor 
is progress in any group a necessity regardless of con- 
ditions. That which we call progress 
No innate tend- rests simply on the survival of the better 
eee adapted, their survival being accom- 
progression. : if eo 
panied by their reproduction. Those 
that live repeat themselves. The “innate tendency 
toward progression” of the early evolutionists is a 
philosophic myth. Progress and degeneration are alike 
the resultants of the various forces at work from gen- 
eration to generation on and within a race or species. 
The same forces which bring progress to a group under 
one set of conditions will bring degradation under 
another. In their essence the factors of evolution are 
no more laws of progress than the attraction of gravita- 
tion is, Cosmic order comes from gravitation. Or- 
ganic order comes from the factors of evolution. Evo- 
lution is simply orderly change. 
Nor is evolution identical with the notion of sponta- 
