In the natural course of things the more people there are in a country the richer it ought to be, because of the advantage of division of labor. Division of labor means that instead of every man having to do everything for himself like Robinson Crusoe, the different sorts of work are done by different sets of men, who become very quick and skilful at their job by doing nothing else. Also their work can be directed by others who give their whole minds to directing it. The time saved in this way can be used in making machinery, roads, and all sorts of contrivances for saving more time and labor later on. That is how twenty workers can produce more than twice what ten can produce, and a hundred much more than five times what twenty can produce. If wealth and the labor of producing it were equally shared, a population of a hundred would be much better off than a population of ten, and so on up to modern populations of millions, which ought to be enormously better off than the old communities of thousands. The fact that they are either very little better off or sometimes actually worse off, is due wholly to the idlers and idlers’ parasites who are plundering them as we plunder the poor bees. I must not, however, let you believe that if we all shared equally the increase of wealth per head could go on for ever. Human beings can multiply very fast under favorable conditions. A single pair, if their posterity managed their affairs well enough to avoid war, pestilence, and premature death, might have twenty million descendants alive at the end of four hundred years. If all the couples now alive were to multiply at that rate there would soon not be standing room on the earth, much less fields to grow wheat in. There is a limit to the quantity of food the earth can yield to labor; and if there were no limit to the increase of population we should at last find that instead of increasing our shares of food by breeding more human beings, we should diminish them. Though we now cultivate the skies by extracting nitrogen from the air, other considerations than that of food will check our multiplication. Man does not live by bread alone; and it is possible for people to be overfed and overcrowded at the same time. After the war there was no exceptional scarcity of food in England; but there was a terrible scarcity of houses. Our cities are monstrously overcrowded: to provide every family they contain with a comfortably spacious house and garden some of our streets would have to be spread over miles of country. Some day we may have to make up our minds how many people we need to keep us all healthy, and stick to that number until we see reason to change it.