80 THE SHADOW OF THE WORLD’S FUTURE 
When all the factors are adequately considered, it 
becomes evident that a world-situation has arisen, 
such that areas capable of carrying much larger popula- 
tions cannot be allowed long to remain empty. It is, 
of course, very foolish to shut one’s eyes to this. The 
economics of the situation point clearly to two issues, 
one for peoples living in dense aggregates of population, 
the other for peoples living in sparsely populated areas. 
For the former birth-control and emigration are 
appropriate policies ; for the latter a high birth-rate 
and immigration are needed. It may be taken as 
certain that any dog-in-the-manger policy by a people, 
for reasons that take no account of the general situa- 
tion, will result, sooner or later, in that policy being 
challenged, and perhaps deservedly so. 
{t is desirable to review the nature of the factors 
that are inimical and those that are favourable to 
increase. But, before doing this, it is advisable to 
examine the things which tend to limit, and those 
which tend to assist the multiplication of a people. 
They are of two kinds, one depending upon man’s 
environment, the other upon his intrinsic characters. 
To put this in another way, one set of factors are 
cosmic and impersonal, the other set are human or 
personal. Both may be described quite briefly, and 
they are important. They are easily recognised. 
As a physically insignificant denizen of the earth, 
Man is dependent upon the energy, resources, and the 
vicissitudes of the system of which his earth forms part. 
He is dependent upon the energies radiating from the 
sun, perhaps more generally those arriving from space, 
and upon those also contained within the earth itself, 
such, for example, as radio-activity, internal heat, etc. 
He depends, too, upon the material of the earth itself. 
These, his natural resources, are known only in part ; 
it is not at all unlikely that his knowledge will be 
rapidly increased concerning the various forms of