1899] METHOD OF TREATING VARIATIONS 419 



is said that we can only tell this by the result, when the " fittest " has 

 proved itself, when the " selection " has already taken place, this simply 

 means that we are unwilling or unable to understand the present. In 

 reality there cannot be two opinions. A plus variation may be "useful" 

 to-day, " harmful " to-morrow, and similarly for a minus one. 



It will be said, however, that " plus " and " minus " do not exist in 

 nature, and that the most " useful " or most " favourable " is the mean 

 or average condition. How then shall we understand the continual 

 recurrence of variations from the mean ? As shown by Galton, the 

 tendency of successive generations is to produce offspring nearer the 

 average than the parents, and hence, on the theory of the survival of 

 the " fittest," or most " favourable " variations, we are unable to explain 

 the presence of extremes. 



Natural selection is based on (1) the rate of increase of offspring, 

 (2) enormous destruction and " struggle," (3) survival of the best fitted 

 to the conditions. If we let our minds run smoothly in the train of 

 thought suggested by the form of the premises, the conclusion is 

 inevitable. But if we inquire more closely into the " struggle " and 

 " destruction " in any particular case, say of the eggs and youug of the 

 herring in the sea, we find ourselves obliged to consider this destruction 

 as indiscriminating and independent of struggle, and that consequently 

 both the " fit " and " unfit " survive ; in other words, we cannot apply 

 these latter words even " metaphorically." 



If natural selection thus fails to interpret present phenomena as 

 shown in the variations of single organs, its difficulties increase when 

 we consider the individuals. From the study of organs we might con- 

 clude that Nature was aiming at the conservation of the average, but 

 when we examine many organs we find that the average of one may 

 be combined with the extremes of others. Hence greater fitness in 

 this or that has to make up for greater unfitness here or there. In the 

 same region the individuals of a group at the same period of life are 

 thus equal in the combination of their characters. This has been shown 

 to be a theoretical deduction from the first proposition, and it has been 

 exemplified under propositions II. and III. Any conception of greater 

 or less fitness is here completely excluded. 



When we turn, however, to different regions and consider different 

 groups of the same species we find that the average of the individuals 

 has changed, and if we examine successive groups in successive regions 

 we find intermediate stages of the averages. It might be thought, 

 then, that natural selection has brought about these differences in the 

 different regions. If so, then we must change our conception of 

 natural selection because there is little or no " struggle " between the 

 different groups, consequently no discriminating destruction and no 

 " survival of the fittest." 



It. is not to the present purpose to criticise further the theory of 

 natural selection, or plead for the theory of probability. This latter, 



