It takes a hardy man to predict the future of the human race for the next million years. Such a man is Charles Galton Darwin, 65, grandson of the late great Charles Robert (The Origin of Species) Darwin, and former Master of Christ College, Cambridge. His just-published book, The Next Million Years (Doubleday; $2.75), is sugar-coated with flowing, donnish English, but it contains a bitter pill for people with faith in human progress. The ultimate future of the race, says Writer Darwin, will be much like its deplorable past.
Darwin is a theoretical physicist, but he invades sociological territory where many sociologists fear to tread. He bases his reasoning about man's future on what is sometimes called "social physics": the idea that the behavior of humans in very large numbers can be predicted by the statistical methods that physicists use with large numbers of molecules.
Gloomy Prediction. Physicists know that the motions of single molecules (e.g., in a gas) are unpredictable. They may move fast or slow and zigzag in any direction. But the impacts of billions of gas molecules against a restraining surface produce a steady push that obeys definite and rather simple laws. In the same manner, Darwin believes, the actions of individual humans are erratic and sometimes remarkable, but the behavior of large numbers of them over long periods of time is as predictable as the pressure of gas. All that is needed is to determine the basic, averaged-out properties of human "molecules."
In Darwin's view, the human molecules have one fundamental property that dominates all others: they tend to increase their numbers up to the absolute limit of their food supply. This is the familiar thesis of Thomas Malthus, a senior contemporary of Grandfather Darwin whose gloomy predictions of starvation have haunted mankind for 150 years.
Grandson Darwin restates Malthus. Human increase, he says, is a "geometrical progression." The more it has increased, the faster it will increase in the future. Food supply, on the other hand, increases only "arithmetically" by simple addition. Past increases do not add to its speed of increase.
The natural rate of increase of passably well-fed peoples, Darwin says, leads them to double their numbers every 100 years. To feed the doubled population, food production must be doubled too. Twice as much land must be cultivated or the old land must be made twice as productive. In the next century the population will double again, and the earth must produce four times as much food as it does now.
Darwin admits that present-day food production can be stepped up. He says, for instance, that a way of turning wood into human food would be a great forward step. The Germans used this very simple process on a large scale during World War II, and "wood molasses" for cattle feed has been produced in small quantities in the U.S.