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End in Sight. But Darwin is not interested in such small details. On his chosen scale of 1,000,000 years they will not be important. Each laborious triumph in food production will only put off the evil day. The earth's population will double again, again and again. After ten centuries of well-fed doubling, it will have increased 1,024 times. In the unlikely event that the food supply will have kept pace, another mere thousand years of doubling will certainly bring the end. In the year 3953 A.D., the earth will be felted with people as thick as mold on a Camembert cheese, and they will need 1,000,000 times as much food as is produced today. "It is quite impossible," says Darwin, "for any arithmetical progression to fight against a geometrical progression." When arithmetic finally loses to geometry, human increase must stop. Most babies that are born will die from the ills of malnutrition before they manage further to replenish the earth.
This sort of reasoning is as old as Malthus, and Darwin knows the arguments that are commonly used against it. One of them is to point out that the earth's population has increased enormously since the time of Malthus, but that much of it is better fed now than it was then. His reply: humans have been living in a fleeting Golden Age that is due to the impact of science on transportation and agriculture. When the Golden Age is over (and its end is in sight), most of the earth's babies will again starve.
Another familiar anti-Malthusian argument is that modern methods of birth control can keep population down to manageable levels. This is actually happening in many nations, including some of those that are best fed. Perhaps such nations as India, where humans are multiplying rapidly, can be induced to do likewise.
A New Species? Grandson Darwin shakes his grey head over this hope. Birth control, he says, is possible biologically but not sociologically. In accordance with a kind of sociological Gresham's Law,* the people who restrain their birth rate will be supplanted by those who do not. Backward but ambitious races are sure to defy the birth rules and increase deliberately at the cost of their prosperous, birth-restraining neighbors.
It would take drastic action by a strong world government, Darwin says, to limit the earth's population, and no strong world government is likely to last for more than a few centuries. As soon as it weakens even slightly, rebellious races or creeds will use the wombs of their women as weapons of social aggression.
Darwin's conclusion is that the human race will have all sorts of ups & downs, perhaps even some more temporary Golden Ages. But the philoprogenitive pressure of its sociological molecules will undo it in the end. No matter what science, government and religion try to do about population, humans will increase like fruit flies in a geneticist's breeding bottle. Stability will come only when starvation sets an impassable limit.
There is one distant ray of hope. By Darwin's reckoning, the average animal species continues for only about a million years without major change. After that time the human species, still very young, may have produced a new species. Perhaps the neo-humans will be able to keep their numbers adjusted to their food supply without the help of starvation.
* That bad currency drives out good.