Darwin's Artificial and Natural Selection 121 
carried out to sea, where it will not be of the least avail if 
one individual has a slight advantage over the others. Dar- 
win admits this, but adds that, if only a thousandth part is 
developed, yet of those that do survive the best adapted 
individuals will tend to propagate their kind in larger num- 
bers than the less well adapted. The argument is not, how- 
ever, so simple as it appears to be on the surface. I pass 
over, for the present, the apparent inconsequence in this 
statement that the best adapted individuals will tend to prop- 
agate their kind in larger numbers. It is not by any means 
certain that this is the case. Darwin’s meaning is, however, 
fairly clear, and can be interpreted to mean this: after the 
fortuitous destruction has finished, there will be a further 
competition of the survivors amongst themselves and with 
the surrounding conditions. In this higher competition, which 
is less severe, small individual differences suffice to determine 
the survival of certain individuals. These are, therefore, 
selected. 
In this argument it is assumed that a second competition 
takes place after the first destruction of individuals has oc- 
curred, and this presupposes that more individuals reach 
maturity than there is room for in the economy of nature. 
But we do not know to what extent this takes place. If only 
as many mature as can survive, then the second competition 
does not take place. If, on the other hand, fewer mature than 
there is room for, then again competition does not take place. 
And if at all times selection is not rigorously carried out, 
everything may be lost that has been so laboriously gained. 
We see then that the result that Darwin imagines would take 
place, can be carried out only when more individuals reach 
maturity than there is room for (if it is a case of competition 
with one another), or that escape their enemies (if it is a 
question of competition with other forms). 
It is instructive to consider some of the examples that 
Darwin has given to illustrate how the process of natural 
