In 2011, the psychologist (and Nobel laureate) Daniel Kahneman proposed that we humans are bimodal animals capable only of two modes of thought. One (which he called “System 1”) is fast, instinctive and emotional. The other (“System 2”) is slower, more deliberative and more logical. The first doubtless evolved when we were hunter-gatherers, and served us well in that reality. The second, involving slow, effortful, infrequent, logical, calculating, conscious thought, came later, as societies became more complex and uncertainty became an integral part of the human condition. Uncertainty is, says David Spiegelhalter, “all about us, but, like the air we breathe, it tends to remain unexamined”. Which is why he wrote a book about how to live with it.
Uncertainty, in Spiegelhalter’s view, is a relationship between an individual and the outside world. And, because of that, our personal judgments play an essential role whenever we are faced with it, “whether we are thinking about our lives, weighing up what people tell us, or doing scientific research”. And tolerance of uncertainty varies hugely among people: some are excited by unpredictability, while others are crippled by anxiety.
