Mr. Neutrino, I'd like you to meet Mr. Bayes

A lot of people who want to believe the faster-than-light neutrino result (and count me as one who would love it to be true!) are displaying a tendency to get quite pissy at those of us who remain skeptical, e.g. see this comment over at Bad Astronomy, which is actually one of the more mild ones. There are accusations of dogmatism, that a "true" skeptic should just follow the results.

That is true as far as it goes, but in my never-humble opinion, if you want to "follow the results" properly, you must be a Bayesian.

The prior probability, based on everything we know about physics, that neutrinos can travel faster than the speed of light in a vacuum, is vanishingly small. The results of countless past experiments would have to be either dismissed, or given a completely different explanation. Anything is possible, of course, but as somebody else said (can't remember where, sorry, no credit), this is "possible" on the order of saying, "Oops, turns out gravity doesn't attract, it repels!"

And Bayes tells us then, that even what would be very solid experimental support for this result in another context is totally unconvincing in this context. Bayes Theorem doesn't quite work this way, but to just simplify it: Let's say last week I gave you trillion-to-one odds that neutrinos could travel faster than light. Then we come up with an explanation for how this result could be an error, but unfortunately it requires a series of coincidences that are a billion-to-one against. I'd still believe it was the billion-to-one error before I'll believe FTL neutrinos were a real thing.

It's probably something much more mundane, of course. Or perhaps it will turn out to reveal some weird new physics where the neutrinos can appear to some observers to exceeding light speed, but in a way that doesn't screw up causality and relativity; that would be neat. But if you're a Bayesian (and you should be), then you can be virtually certain that it's not really FTL. Sorry, sci-fi fans. No galactic empires for you.