46 THE SHADOW OF THE WORLD’S FUTURE 
resources which our increasing knowledge and power 
have placed at our disposal. It is only too easy to 
make the advantages, which accrue through a more 
sensible use of our earth’s surface, disappear. Thus 
comparing the different standards-of-living which are 
characteristic of the various peoples of the earth at 
the present time, we see that there is no fixed limit to 
human desire for luxury. If, then, we consider the 
further possible expansion of the spirit of luxuriousness, 
we recognise that there is no unique solution to the 
problem before us. For there is no intrinsic limit to 
human desires, and the luxury of to-day tends to 
become the penury of to-morrow. 
It is because of this that the population-problem is 
not merely a mathematico-physical one. It involves 
our whole conception of life. Our social and our 
ethical traditions are real factors in the adjustment 
of communities to world-conditions. The evidence of 
this may be seen in a nation’s consideration, for example, 
of what may reasonably be expected by its citizens in 
respect of the standard-of-living to which it deems 
them to be entitled. Thus it immediately affects the 
solution of the migration question. One nation has 
experts who solve its population-possibilities on the 
assumption that its existing mode of living is to 
continue, whatever may happen elsewhere. Another 
people object to the rapid influx of others because 
it affects the non-economic rate, judged by world- 
standards, at which, for example, even unskilled labour 
is rewarded. 
The significance of the acceleration of the rates of 
production of the minerals and metals, before referred 
to, the rate at which forests are being exploited for 
timber wants and for paper, and indeed also that of 
the mere rate of human increase, is readily seen by 
considering the actual meaning of any such rates, in 
a suitable way. The rate of increase of individual