Commentary It is easier to adhere to preconceived ideas than to follow wherever the evidence may lead. Intellectual honesty is more often praised than practised, and more people read to confirm what they already think to be the case than read to expand their mental horizons. Perhaps it would be a good idea if, instead of making new year’s resolutions, we reflected upon how many ideas or opinions we had abandoned in the previous twelve months in the light of evidence. I suspect that in most cases it would not be many, or even a single one. I do not exclude myself from this generalization. In his “Autobiography,” Charles Darwin said that he always noted down anything that made difficulties for his theory, for otherwise he was sure to forget it. I doubt that he was alone in this propensity; and many of us can “smell” in advance, so to …