Pascal Diethelm, OxyRomandie, Geneva, Switzerland
Christmas is a time when many entirely rational people whose views are based solidly on empirical evidence the rest of the year suspend their critical faculties and say things they know to be untrue. Just in case any young children have picked up their parents’ copy of the BMJ, we won’t go into detail except to say that the subject of these falsehoods traditionally originates in the far north. Such stories are harmless and those telling them will, when their children reach an appropriate age, abandon the pretence. Yet other people hold views that are equally untrue and do so with an unshakeable faith, never admitting they are wrong however much contradictory evidence they are presented with.
Some of these views are harmless, but others cost lives. It is easy to think of contemporary examples. “HIV is not the cause of AIDS.” “The measles, mumps, and rubella vaccine cannot be considered safe.” “Second hand smoke is simply an irritant and there is no conclusive evidence that it is dangerous.”And, with potentially the greatest consequences for our species, “the evidence that the world is warming is inconclusive, and, if not, the evidence that global warming is caused by anthropogenic carbon emissions is unproven.”