64 THE EVOLUTIONARY THEORY 



tors operate in the natural evolution of species which 

 cannot rightly be described by the term selection. Nor 

 is this all. It is urged that selection actually retards 

 the development of new species, its effect being to 

 preserve useful types at the expense of variants there- 

 from. Doubts have been expressed as to the alleged 

 fierceness of the struggle for existence ; and it has been 

 maintained that new forms can originate only when 

 the conditions are favourable, that is, when a struggle 

 for existence is unnecessary. 



I have grven you only a very rapid and incomplete 

 summary of the objections that have been raised against 

 the Darw^inian theory, and it would be foreign to the 

 general purpose of these lectures either to discuss them 

 or to estimate the value of the repHes which have been 

 made to them. They are obviously of unequal force, 

 and a few of them may perhaps be looked upon as 

 incidental problems for solution rather than as reasons 

 for rejecting Darwin's theory.^ But the real difficulties 

 are sufficiently numerous and formidable to account 

 for the reaction which has occurred against pure Dar- 

 winism — a reaction which has resulted from fuller 

 biological investigation, and not from any theological 

 influence. A close examination of these difficulties 

 shows that they do not militate against belief in a 

 natural evolution of species; and they have not caused 

 any weakening of that belief. Nor have they brought 



1 In his Origin of Species, especially the later editions, Darwin 

 discussed them, and his candour in acknowledging the force of 

 some of them is admirable. 



