Can we agree on the following: if you pick a random stupid person and ask for an opinion on B, and the stupid person says B is false, this cannot be evidence against B unless you have background knowledge on the fraction of people who think B, in which case all the work is really being done by the indirect inference about the opinions of smarter people, so calling the stupid person's opinion negative evidence is misleading even if strictly speaking correct?
I'm not sure if I'd agree on that, especially when it comes to political topics, stupid people with strong exposition to mass media tend to perform significantly worse than random: Thus using the opposite of what said stupid person supported seems to have at least a mildly higher chance of being true in T/F question.
Piper had a point. Pers’nally, I don’t believe there are any poorly hidden aliens infesting these parts. But my disbelief has nothing to do with the awful embarrassing irrationality of flying saucer cults—at least, I hope not.
You and I believe that flying saucer cults arose in the total absence of any flying saucers. Cults can arise around almost any idea, thanks to human silliness. This silliness operates orthogonally to alien intervention: We would expect to see flying saucer cults whether or not there were flying saucers. Even if there were poorly hidden aliens, it would not be any less likely for flying saucer cults to arise. The conditional probability P(cults|aliens) isn’t less than P(cults|¬aliens), unless you suppose that poorly hidden aliens would deliberately suppress flying saucer cults.1 By the Bayesian definition of evidence, the observation “flying saucer cults exist” is not evidence against the existence of flying saucers. It’s not much evidence one way or the other.
This is an application of the general principle that, as Robert Pirsig puts it, “The world’s greatest fool may say the Sun is shining, but that doesn’t make it dark out.”2
If you knew someone who was wrong 99.99% of the time on yes-or-no questions, you could obtain 99.99% accuracy just by reversing their answers. They would need to do all the work of obtaining good evidence entangled with reality, and processing that evidence coherently, just to anticorrelate that reliably. They would have to be superintelligent to be that stupid.
A car with a broken engine cannot drive backward at 200 mph, even if the engine is really really broken.
If stupidity does not reliably anticorrelate with truth, how much less should human evil anticorrelate with truth? The converse of the halo effect is the horns effect: All perceived negative qualities correlate. If Stalin is evil, then everything he says should be false. You wouldn’t want to agree with Stalin, would you?
Stalin also believed that 2 + 2 = 4. Yet if you defend any statement made by Stalin, even “2 + 2 = 4,” people will see only that you are “agreeing with Stalin”; you must be on his side.
Corollaries of this principle:
1Read “P(cults|aliens)” as “the probability of UFO cults given that aliens have visited Earth,” and read “P(cults|¬aliens)” as “the probability of UFO cults given that aliens have not visited Earth.”
2Robert M. Pirsig, Zen and the Art of Motorcycle Maintenance: An Inquiry Into Values, 1st ed. (New York: Morrow, 1974).
3See Scott Alexander, “The Least Convenient Possible World,” Less Wrong (blog), December 2, 2018, http://lesswrong.com/lw/2k/the_least_convenient_possible_world/.
4See also “Selling Nonapples.” http://lesswrong.com/lw/vs/selling_nonapples.