82 THE PEOBLEM AMONG MEN 



We have only to think of the rise of Japan to the position of a great 

 power in the last half of the nineteenth century. The rise of Japan 

 was an outstanding fact in the history of that period and it was 

 clearly in the main, if not wholly, a traditional and not a germinal 

 change. It took the form of a rapid absorption of European 

 tradition. The evolution of reason has thus introduced into the 

 problem of the causes of human history a factor which is not 

 present in the case of other species ; it has also modified the course 

 of selection, but this, as we have seen, has not made a fundamental 

 difference between the position of man and that of species in 

 a state of nature. 



The problem before us is therefore as follows. Owing to the fact 

 of reproduction the population problem in both its aspects exists 

 for all species in a state of nature and further presents funda- 

 mentally the same features for all such species. The ancestors of 

 man were at one time subject to the same conditions from which 

 they have, step by step, moved away owing to the development 

 of the faculty of reason. We have to trace the causes and results 

 of this moving away — of the progressive modifications of the 

 conditions existing among species in a state of nature. 



Though the problem has two aspects, they are closely inter- 

 woven. Changes which affect numbers also influence the quality 

 of population. The discussion has hitherto taken the form of an 

 introduction to the problem as a whole, and the two next chapters, 

 the subject-matter of which will be indicated in what follows, will 

 also be devoted to certain problems which equally bear upon both 

 aspects of the question. From the seventh chapter onwards the 

 two aspects are treated independently ; we deal first with the 

 quantitative and then wdth the qualitative aspect. Nevertheless 

 we shall, when dealing with the quantitative problem, present 

 evidence which we shall consider again later when treating of the 

 quahtative problem. The book thus falls into three parts ; the first 

 six chapters are introductory to the problem as a whole, the next 

 six chapters are concerned with problems of quantity (though 

 many of the facts brought forward will be found also to bear later 

 upon quality), and the following nine chapters with problems of 

 quality. The last chapter sums up our conclusions as to the whole 

 problem. 



2. We may next ask what data are required in order that we 

 may look into the changes away from the conditions under which 



