It cannot be disputed that the transformation by which the propagation of the race became deliberate and voluntary has not been established in social custom without a certain amount of protestation from various sides. No social change, however beneficial, ever is established without such protestation, which may, therefore, be regarded as an inevitable and probably a salutary part of social change. Even some would-be scientific persons, with a display of elaborate statistics, set forth various alarmistic doctrines. If, said these persons, this new movement goes on at the present pace, and if all other conditions remain unchanged, then all sorts of terrible results will ensue. But the alarming conclusion failed to ensue, and for a very sufficient reason. The assumed premises of the argument were unsound. Nothing ever goes on at the same pace, nor do all other conditions ever remain unchanged. The world is a living fire, as Heraclitus long ago put it. All things are in perpetual flux. Life is a process of perpetual movement. It is idle to bid the world stand still, and then to argue about the consequences. The world will not stand still, it is for ever revolving, for ever revealing some new facet that had not been allowed for in the neatly arranged mechanism of the statistician. It is perhaps unnecessary to dwell on a point which is now at last, one may hope, becoming clear to most intelligent persons. But I may perhaps be allowed to refer in passing to an argument that has been brought forward with the wearisome iteration which always marks the progress of those who are feeble in argument. The good stocks of upper social class are decreasing in fertility, it is said; the bad stocks of lower social class are not decreasing; therefore the bad stocks are tending to replace the good stocks.[11] It must, however, be pointed out that, even assuming that the facts are as stated; it is a hazardous assumption that the best stocks are necessarily the stocks of high social class. In the main no doubt this is so, but good stocks are nevertheless so widely spread through all classes--such good stocks in the lower social classes being probably the most resistent to adverse conditions--that we are not entitled to regard even a slightly greater net increase of the lower social classes as an unmitigated evil. It may be that, as Mercier has expressed it, "we have to regard a civilized community somewhat in the light of a lamp, which burns at the top and is replenished from the bottom."[12]