Double jeopardy

Abstract

For human survival we require two independent cum-risks: one for natural hazards, the other for man-made. The former is simply calendar time. Since an asteroid is just as likely to strike one year as another, its risk gauge runs at a constant rate; in other words it is a clock. For man-made risks, the virtual gauge is some imprecise measure of modern hazardous activity. It indicates serious danger due to our extreme inexperience—only a half century of coping, in contrast with 2,000 centuries of exposure to natural hazards. We must balance the two measures of risk exposure, the old one that says we are safe against the new one that warns of danger.

’Tis better to be roughly right than precisely wrong. —one variation by John Maynard Keynes