Following last month’s withdrawal of fact-checking on facebook Meta, there’s been a small resurgence in critical perspectives on fact-checking.

In my personal view, the about-turn in Meta policy was motivated by a desire to perform ‘obeisance and tribute’ to a new US administration. Meta values freedom of speech as far as it aligns with Meta’s purely corporate objectives, and I wouldn’t read too much more into it.

That said, in this moment where the fact-checkers are themselves being held to account, I’d like to throw in a test case for where fact checking reaches its limits.

Say, for example, someone makes the following claim on Facebook:

I believe in aliens.

Firstly, there is a non-negligible group of people in the UK who agree with that claim. For better or worse, belief in alien life is definitely part of our culture. Belief in aliens is not afforded the same respect as a religious convictions, but it would arguably be recognised under broad legal protections for ‘freedom of thought’.

Secondly, the thing about UFOs is that they’re, well, unidentified objects, nobody knows what they are. You can’t ‘believe the science’ because it’s a belief grounded in the absence of evidence. Very convenient!

So, we would have to rely on reasoning and theory to argue degrees of plausability, and that’s already uncomfortable territory for fact-checkers.

It is plausible, even academically respectable, to suggest there might be intelligent life on other planets.¹ It’s less plausible to suggest that a flying saucer full of little green men landed in rural Kentucky in August 1955.

There’s an alternative explanation underlying the wave of UFO hoaxes in the 1950s: they coincided with a moment we now know that the US air force was testing spy planes. Have you seen an unidentified aircraft near that new military base in the desert? No citizen, it was probably aliens. It might just be a conspiracy theory, but it’s possible the flying saucer phenomenon was actually itself a disinformation campaign which got slightly out of hand.

Next time someone talks about the difficulty of fact-checking on social networks, ask them whether they think aliens exist.