When Authorities Disagree

When two scientific authorities, people entitled to respect in a given field of study, disagree, how should a non-expert respond?  Remember, she is not an authority herself.  

Some people respond by studying closely what each side of a science dispute has said, but often that is no help. Sometimes it can be, as in the case of scientists who found a statistical correlation in some part of the country between slightly lower IQ scores and fluoridated water.  They concluded that low IQ scores led to fluoridation (or the reverse). Even a non-expert like me might notice that (1) IQ scores reflect mostly the ability to score well on IQ tests, so most scientists don't take them seriously and (2) it is a logical fallacy to attribute cause-and-effect to a statistical correlation unless you can explain  how the correlation actually works in flesh and bone. Let's say that there is a statistical correlation in Sonoma County between drinking pinot noir and getting whooping cough. This does not prove that pinot noir causes whooping cough (an epidemic in Sonoma County because so many on the way way left reject vaccinations on the basis of long refuted junk science).

Most scientific disagreements aren't so obvious. How does a layman choose between two scientists in disagreement? That answer is that you see what the genuine authorities in the field say. In cases like climate change, fluoridated water and vaccinations, you find out where the World Health Organization stands. The  WHO might be wrong, of course, but odds are that it is right. You can double-check by looking up the American Dental Association, the Surgeon General, the National Cancer Institute and so on. If they all say the same thing, the chances are excellent that they've got it right. It is true that the Sierra Club is opposed to fluoridation, but when you break your ankle, you don't go by ambulance to the Sierra Club to get your leg set. You go to a medical expert.