Book excerpt – ‘Filters Against Folly’ by Garrett Hardin
Numeracy is the art of putting number to things, that is, assigning amounts to variables in order that practical decisions may be reached. That aspect of education (beyond mere literacy) which takes account of quantitative aspects of reality. No one connected with business needs to be convinced of the central importance of numerate thinking. The numerate temperament is one that habitually looks for approximate dimensions, ratios, proportions, and rates of change in trying to grasp what is going on in the world. This numerate orientation is probably within reach of most normal people.
Mutually exclusive categories make the writing of regulatory laws simple, of course, but nature seldom draws a sharp line at which “unsafe” begins. “Where is the dividing line between safe and unsafe speeds for an automobile? What is the safe amount of radiation for a human…nature is silent. Nature doesn’t tell us when “safe” slips into “unsafe”; men and women, reasoning together, must legally define “unsafe”. Wherever the line is drawn, the decision is an arbitrary one. A speed of 55 mph is not significantly and probably more dangerous than 54.473 mph, we merely agree to begin taking legal notice above that number. Thus it is with all numerical standards of safety. The final point of the decision is always arbitrary.
Example – The Delaney Amendment was an amendment to the Pure Food & Drug Act in the USA. Concerned with the growing evidence that many otherwise useful substances can cause cancer, Congress decreed that henceforth, whenever a chemical at any concentration was found to cause cancer – in any fraction of any species of animal – that substance must be totally banned as an additive to human food. Such is the “zero tolerance” criterion written into the law. The amendment is a monument to innumerate thought. “Safe” and “unsafe” are literate distinctions; nature is numerate. Everything is dangerous at some level. Even oxygen, essential to human life, becomes lethal as the concentration approaches 100%. Scientists are continually increasing the sensitivity of their measuring instruments. If a substance provable increases the incidence of cancer at a concentration of 1/10,000, one should probably ban it at that concentration in food, and perhaps at 1/100,000. But what about 1/1000,000? With sufficient sensitivity to measuring instruments we could be driven to conclude that nothing is safe to eat. But the alternative to eating is fasting, and that is lethal, too.
Why was the scientifically indefensible amendment enacted into law? A psychoanalyst might suggest that the high average age of congressmen, particularly in the 1950s, produced an immoderate fear of cancer, which led these otherwise intelligent men to abandon rationality. This is not the sort of hypothesis that can be easily proved, but it is plausible.
All things are poisons, for there is nothing without poisonous qualities.
Paracelsus
Most valuable antibiotics, analgesics, anesthetics, and tranquilizers have bad effects on some people at some concentrations under some conditions of use. All effective medicines are poisons to some extent. Beneficent poisons, if you wish, but poisons nonetheless: these should be used with quantitative discretion, with suspicion, and with vigilance.
Quantities matter. Number matter. Duration of time matters.
Our attitude towards pollution also needs to be passes through a numerator filter. Had all environmentalists been imbued with the numerate spirit of science, there would have been fewer controversies in the past. Unfortunately, many of the enthusiasts who moved into the environmental movement brought with them an almost wholly literate orientation. They detested pollution and craved purity. Absolute purity. They wanted to enforce zero tolerance to all environmental pollutants, not just on carcinogens. Such innumerate enthusiasts would, if they could, universalize the Delaney disorder.