> I know people I would not want to debate with on the question, “What is 2 + 2?” because they could go down a rabbit hole that’s over my head and leave me eith

> I know people I would not want to debate with on the question, “What is 2 + 2?” because they could go down a rabbit hole that’s over my head and leave me either exhausted or convinced the answer may not be four. I've experienced something similar. I have a PhD in astronomy, and that tends to attract a certain sort. I became friends with a guy a while back who had discovered a group of geocentrists and was genuinely curious if there was anything to it. He lent me a book he had bought from them that was about 800 pages long making the case for geocentrism. Now you might think that it's an easy enough thing to prove that geocentrism is wrong. What about the Foucault pendulum? Surely that at least proves that the Earth rotates! But the geocentrists had considered that and a whole lot more to boot. The book was meticulously researched and went through dozens of historical experiments that demonstrate the motion of the Earth and then presented an explanation as to how these results were, in fact, consistent with their geocentric model. Many of these experiments are so obscure that they've pretty much been forgotten by everyone except historians of science. Of course it was all nonsense, but it was a surprisingly sophisticated form of nonsense. Fortunately for me by the time they were trying to explain away certain results in quantum physics they started to get pretty obviously out of their depth and were making easy to catch mistakes. But without that knowledge, discovering where they went wrong in their logic was non-trivial. I could certainly see how it could be a plausible argument for someone without a background in physics.