When it comes to low probability-high impact (even catastrophic) risk, the judgment of ordinary people, it seems, is not to be trusted. Emotions (like fear) are said to override our capacity for rational response. As one commentator puts it, “we have a confounding habit of worrying about mere possibilities while ignoring probabilities, building barricades against perceived dangers while leaving ourselves exposed to real ones.” But what in fact is a ‘rational’ response? How do we know which risks are “real”?
The conventional advice is to turn to experts, i.e., to those skilled in the rules of rational (cost-benefit) analysis. The trouble with this advice is that when it comes to assessing the risk of catastrophic events, the rules conventionally employed fail most common sense criteria for rationality. It is argued that sometimes the heuristics employed by non-experts – the very heuristics held responsible for misguiding ordinary judgment – can outperform (in the sense of providing more reliable guides) the analyses that are taken as providing our gold standard of rationality.
The “heuristic of fear” that Hans Jonas proposed as a guide for “an ethics of responsibility for distant contingencies” may well be a case in point. According to Jonas, the heuristic of fear serves to teach us what it is we truly cherish, and hence can inform us as to what we must do. I will argue – following Jonas – that, when faced with threats of distant catastrophe, fear may be not only appropriate, but also a legitimate and perhaps necessary ingredient of a truly rational response.