THE THEORY 5 
3. Natural Selection, just as it brings about 
diversity of structure by acting on individuals, 
so it must bring about diversity of structure 
by acting upon associations of individuals. 
4. These diversities of structure found in 
the unequally valuable members of societies, 
control Natural Selection in such a way that 
the less valuable are more liable to destruction 
than the more valuable. 
1. If Darwin’s theory of Natural Selection 
accounts for the evolution of organic matter, 
if Natural Selection appreciates the more or 
less small, continuous, or discontinuous varia- 
tions which occur among the individuals of a 
species, or even if it cannot appreciate these 
but only larger variations, mutations — 
if Natural Selection can do this, it must 
appreciate the relatively great differences 
which frequently distinguish male from female, 
old from young. If the scales of Natural 
Selection can detect a small difference be- 
tween two individuals, it must be able to 
easily detect great differences. 
If chance alone does not govern the selec- 
tion of very similar individuals, it is unlikely 
to do so when the individuals are very 
different. If the chance of taking one bird 
out of two hen birds is not half, because, 
