Sunday, August 12, 2012
Teach Your Children (Probability Theory) Well
So here we are, in the waning weeks of summer 2012, facing a remarkable paradox: on the one hand, we have a record-shattering drought, crop failures and a threat to global food security, and on the other not a whisper of climate change or its challenges in a political contest on track to suck as much as $2 billion into advertising.
There is a political economy dimension to this mess, of course: disruption of the carbon cycle remains an inconvenient problem, especially for those who profit mightily from it. A part of our paralysis, however, can be chalked up to the fact that the twentieth century’s most important cognitive revolution, the shift from deterministic to probabilistic thinking, is still confined to a tiny sliver of the population.
Although the foundations stones of probability theory were set in earlier centuries, it was not until the first decades of the twentieth that the practical uses of probability, in forecasting and hypothesis testing, emerged. At the same time, humans acquired vast new powers to manipulate nature and each other—powers that could be understood and regulated only through an understanding of probabilistic relationships. Whether the topic is food additives, air pollution, or the effect of propaganda campaigns of various intensities and expense on voter behavior, intelligent discussion is impossible without a familiarity with the nature of stochastic processes.
Yet most people think in much simpler terms. A either causes B or it doesn’t. If you can point to an A without a corresponding B, there’s no cause—end of story. Poverty doesn’t hold back promising students; just look at all the kids who succeed despite their background. Don’t worry about the warning label on the package: smoking can’t cause cancer because I know someone who is almost 90, in great health and still smokes a pack a day.
I know that there are studies that tie beliefs about climate change to value systems, political affiliation and so on, but just listen to the debate between worriers and deniers on its own terms. The worriers, like me, point to the increasing likelihood of catastrophic impacts; it means something to us to say that, while a specific climate event cannot be tied deterministically to carbon loading, droughts and other severe impacts are now more likely to occur. The deniers point to individual exceptions like periods of cooler weather and say, see, you can’t prove causation—it’s all a hoax.
Thinking probabilistically isn’t something we’re born with. It has to be taught; in fact it has to be taught over and over because it seems to go against our natural cognitive tendencies. A lot of readers of this blog (insofar as a high percentage of a low number can be “a lot”) are teachers. Whatever your subject, there is no more important goal you can strive for.