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 



