[26] See, for instance, H.F.  Osborn, The Origin and Evolution of Life, 1918, Chapter III.

To-day, we are often told, the majority of human beings belong either to the Undesired Class or the Undesirable Class.  To realise that this is so, we are bidden to read the newspapers or to walk along the streets of the cities—­whichever they may be—­wherein dwell the highest products of our civilisation.  In the better class quarters it is indeed the Undesirable Class that seems to predominate, and in the poor quarters, the Undesired.  Yet, viewing our species as a whole, the two classes may be seen to walk hand in hand along the same road, and in proportion as our nobler instincts germinate and develop, we must doubtless admit that it ought to be our active aim to make that road for both of them—­socially though not individually—­the Road to Destruction.

To stem the devastating tide of human procreativeness, however, easy as it may seem in theory, is by no means so easy as some think, especially as those think who believe that the human race stands on the brink of suicide.  For there is this about it that we must never forget:  the majority of those born to-day die before their time, so that by diminishing the production of the unfit, as well as by the progressive improvement of the environment that automatically accompanies such diminution, we may make an imposing difference in the appearance of the birth-rate, whilst yet the population goes on increasing rapidly, probably even more rapidly than before.  It needs a most radical and thorough attack on the birth-rate before we can make any real impression on the rate of increase of the population, to say nothing of its real reduction.  There is still an arduous road before us.

True it is that we have two opposing schools of thought which both say that we need not, or that we cannot, make any difference by our efforts to regulate the earth’s human population.  According to one view the development of population, together with the necessity for war which is inextricably mixed up with a developing population, cannot be effected without, as one champion of the doctrine is pleased to put it, “shattering both the structure of Euclidean space and the psychological laws upon which the existence of self-consciousness and human society are conditional."[27] In simpler words, populations tend to become too large for their territories, so that war ensues, and birth-control can do nothing because “it is doubtful whether a group in the plenitude of vigour and self-consciousness can deliberately stop its own growth.”  The other school proclaims human impotence on exactly opposite grounds.  There is not the slightest reason, it declares, to believe that birth-control has had any but a completely negligible influence on population.  This is a natural process and fertility is automatically adjusted to the death-rate.  Whenever a population reaches a certain stage of civilisation and nervous development its procreativeness, quite apart from any effort of the will, tends to diminish.  The seeming effect of birth-control is illusory.  It is Nature, not human effort, which is at work.[28]