** Factors of Organic Evolution” rog 
in the same proportion do there arise obstacles to the in- 
crease of any particular power, by ‘ the preservation of 
favoured races in the struggle for life’ ” (that is to say, 
through mere survival of the luckiest). ‘‘ As fast as the 
faculties are multiplied, so fast does it become possible for 
the several members of a species to have various kinds of 
superiority over one another. While one saves its life by 
higher speed, another does the like by clearer vision, 
another by keener scent, another by quicker hearing, 
another by greater strength, another by unusual power 
of enduring cold or hunger, another by special sagacity, 
another by special timidity, another by special courage ; 
and others by other bodily and mental attributes. Now it 
is unquestionably true that, othcr things equal, each of 
these attributes, giving its possessor an equal extra chance 
of life, is likely to be transmitted to posterity. But there 
seems no reason to believe it will be increased in subsequent 
generations by natural selection. That it may be thus 
increased, the animals not possessing more than average 
endowments of it must be more frequently killed off than 
individuals highly endowed with it; and this can only 
happen when the attribute is one of greater importance, 
for the time being, than most of the other attributes. 
If those members of the species which have but ordinary 
shares of it, nevertheless survive by virtue of other superior- 
ities which they severally possess, then it is not easy to see 
how this particular attribute can be developed by natural 
selection in subsequent generations.” (For if some other 
superiority is a greater source of luck, then natural selection, 
or survival of the luckiest, will ensure that this other superi- 
ority be preserved at the expense of the one acquired in 
the earlier generation.) ‘‘ The probability seems rather to 
be, that by gamogenesis, this extra endowment will, on 
the average, be diminished in posterity—just serving in the 
long run to compensate the deficient endowments of other 
individuals, whose special powers lie in other directions ; 
