Two major threads weave through Joel Cohen’s book How Many People Can the Earth Support? (1995): the insufficiency of our present understanding, and the finiteness of time.
Three laws of intellectual modesty describe the insufficiency of our present understanding. The Law of Information asserts that 97.6 percent of all statistics are made up. Knowledge of the present and past is highly imperfect. The Law of Action asserts that it is difficult to do just what you intended to do. Action and inaction achieve desired consequences imperfectly. The Law of Prediction asserts that the more confident an expert attaches to a prediction about future human affairs, the less confidence you should attach to it. Knowledge of the future is highly imperfect.
The finiteness of time, the second thread in the book, limit’s the abilities of individuals and of societies to solve problems. For each human being, time is finite. I want to eat and drink today. As a privileged inhabitant of a wealthy country, I can postpone buying a new car for several years, but the requirements of poor people for subsistence are not so elastic in time. Those who want firewood to cook a meal today will break branches from the last tree standing if they believe that otherwise their children may not surive to lament the absence of trees 20 years hence. In the American legal system, the finiteness of time to satisfy basic human wants is recognized in a phrase: justice delayed is justice denied.
Efforts to satisfy human wants require time, and the time required may be longer than the finite time available to individuals. There is a race between the complexity of the problems that are generated by increasing human numbers and the ability of humans to comprehend and solve those problems. Educating people to solve problems takes time. Developing traditions of stable, productive cooperation takes time. Building institutions with the resources to make educated people into productive problem-solvers takes time. Even with educated, cooperative people and appropriate institutions at hand, understanding and solving problems take still more time.
Time is the greatest binding constraint for an individual. In the long run, as Keynes astutely observed, we are all dead. Time, however, is not the greatest binding constraint in the case of institutions and the collection of institutions we call a nation state or the even bigger collection of institutions we call the global economic system. The binding constraint there is the enormous complexity of the systems relative to the bounded rationality of humans.
Given the complexity of the system, and the bounded rationality and finiteness of individual human existence, the challenge for an individual is to somehow gain a sufficiently informed view of the fundamental problems so as to contribute in some way, however small, to the solutions.
Since we cannot contribute to the solution of all problems, we have to choose the battles we individually wish to fight. For me, the population problem is paramount for human welfare. As I have recorded before (here, here, here and here), of all the problems facing India, the population problem is perhaps the most neglected and misunderstood. I choose it to be the battle that I most want to fight and, I hope for India’s sake, win.