A REMINDER FROM MATT RIDLEY: Science Is About Evidence, Not Consensus.

Last week a friend chided me for not agreeing with the scientific consensus that climate change is likely to be dangerous. I responded that, according to polls, the “consensus” about climate change only extends to the propositions that it has been happening and is partly man-made, both of which I readily agree with. Forecasts show huge uncertainty.

Besides, science does not respect consensus. There was once widespread agreement about phlogiston (a nonexistent element said to be a crucial part of combustion), eugenics, the impossibility of continental drift, the idea that genes were made of protein (not DNA) and stomach ulcers were caused by stress, and so forth—all of which proved false. Science, Richard Feyman once said, is “the belief in the ignorance of experts.”

My friend objected that I seemed to follow the herd on matters like the reality of evolution and the safety of genetically modified crops, so why not on climate change? Ah, said I, but I don’t. I agree with the majority view on evolution, not because it is a majority view but because I have looked at evidence. It’s the data that convince me, not the existence of a consensus.

As it should be. After all, within my lifetime it was the “scientific consensus” that homosexuality is a mental disease.