We here at Bad Astronomy Central (and by we, I mean me) have heard just about every silly claim you can imagine. Planet X, the Moon Hoax, astrology, creationism... you know the story.
It's not just astronomy, of course. Ghosts, spirits, crystals, homeopathy, prayer... these all go totally against what we know to be real, what we know to be true.
But when I (or countless other rationalists) point this out to the True BelieverTM, we always get the same response: "Science doesn't know everything!"
Well, duh. We never said it did. But it's the best tool humans have to distinguish truth from fantasy.
And that's what makes me even madder when I hear scientists or science journalists buy into the pseudoscience framing. How many times have you heard a scientist say, "We can't test the supernatural"? The idea being that prayer, ghosts, what-have-you, are not subject to scientific scrutiny.
The latest blurting about this comes from a scientist quoted in a book review. In the review, the science journalist says:
As scientists at Iowa State University put it last year, supernatural explanations are "not within the scope or abilities of science."
This is 100% wrong. Any claim, any explanation of an event, definitely falls within the scope of science. That's because science is a method of investigation.
If someone says prayer helps people get healthy, then there is a clear methodology to test this (double blind tests with statistically large samples, as has been done -- conclusion: prayer doesn't work). If someone says a ghost makes noises in their house, then that noise is recordable, and the house itself testable: it may be old and creaky, or has pipes which thermally disturb the wood, or has rats in the walls. Creationists say the world is 6000 years old. We know this can be tested, literally thousands of ways. The conclusion: well, you know the conclusion.
Let me be clear: if you say there is a cause for an event, then there is a way to test that cause. It may not be easy, and it may involve elimination (like destroying the Moon Hoax arguments one by one until the only viable conclusion left is that we did indeed go to the Moon). The only claims I can think of that cannot be tested are solipsism (which to me is an interesting idea to toy with, but an intellectual dead end since it tells you nothing) and the actual existence of God.
For the latter, I say that it may not be possible to test for the existence of God, but people do make claims about what God has done. If those claims are true, then they can be tested.
Anything that has a physical, measurable manifestation is within the realm of science.
Which leaves me to say the thing I have said so many times, but which so many people don't seem to want to understand: there is no such thing as the supernatural. If something exists, then it is real, and it is natural.
I don't expect people at large to pick up on this, necessarily, but I sure think scientists should.