II 



THE BASIS OF THE POPULATION PROBLEM: 

 (1) THE QUANTITATIVE ASPECT 



1 . IN what follows the evolutionary position is taken for granted. 

 It is assumed, that is to say, that the higher forms of life have 

 evolved from lower forms. If we make this assumption, we must 

 suppose that at one time the ancestors of man were living under 

 those conditions to which species in a state of nature are now 

 subject. By species in a state of nature are meant all species of 

 animals and plants with the exception of man and those species 

 which have been domesticated by him. It is the object of this 

 and the following chapter to show that among species in a state 

 of nature the population problem exists both in its quantitative 

 and qualitative aspects, and further that in certain particulars 

 of fundamental importance the position is the same for all such 

 species. Certain propositions may be laid down which hold good 

 for any one of them, and in these chapters it is proposed to show 

 what it is that may be affirmed with regard to all of them. It 

 follows that, since among the ancestors of man the population 

 problem must at one time have taken this form, we shall, as the 

 result of the discussion, arrive at a basis from which we can 

 proceed to study the shape which the problem in its double 

 aspect has assumed in the case of man. 



It is necessary to emphasize the fact that this argument does 

 not take the form of developing an analogy between the position 

 of man and that of species in a state of nature. What we are 

 doing is merely to attempt to ascertain the conditions under 

 which the ancestors of man lived, in order that we may follow 

 the changes which have taken place. Further, it may be well 

 to point out that the argument in these chapters will follow 

 rather an unusual course. It may seem that certain facts of 

 considerable general importance are passed over and others of 

 little obvious importance emphasized. The justification for this 

 course will be apparent later when we come to deal with the 

 position with regard to man ; for this sketch is not introduced 



