A funny thing happened on the way to the second nationwide Earth Day in 1990. Twenty years earlier the first Earth Day had been saluted with much talk about population problems. At that time world population stood at 3.6 billion. But when the second Earth Day rolled around, the topic of population was almost completely ignored. Was that because world population had stopped growing? Hardly: in the intervening two decades it had increased 47 percent to an estimated 5.3 billion— an increase of 1.7 billion (more than six times the present population of the United States). Common sense tells us that the per capita share of environmental riches must decrease as population numbers increase, and waste disposal necessarily becomes an ever greater problem. Of course common sense is sometimes wrong. But if that is so in this instance, the celebrants of the 1990 Earth Day should have been shouting, "We've found the secret of perpetual growth!" A few incurable optimists did defend this position, but most people lumped their claims with those of the flat earthers, ignoring both. The celebrants were generally silent about the 47 percent increase in population. Why? The answer comes in two parts, the first being historical. It is now known that the planners of Earth Day 1990 were under economic pressure to leave population out of the picture. When directors of philanthropic foundations and business concerns were solicited for financial support they let it be known that they would not look kindly on a population emphasis. Money talks, silence can be bought. (Why the bankrollers shied at population will become clear later.) The second aspect of the answer is more subtle. It has long been recognized that some of our most deeply held views are not neat, precise propositions but broadly "global" attitudes that act as the gatekeepers of the mind, letting in only those propositions that do not challenge the dominant picture of reality. Germans call such gatekeeper attitudes Weltanschauungen, an impressive mouthful that is quite adequately translated as "worldviews." For all but the last few hundred years of human history the dominant worldview was a limited view: resources were limited, human nature was fixed, and spending beyond one's income was a sin. This essentially conservative perception prevailed until about 1600.
Proportional Hazard Model: A Discussion with Serial Killer Data
