is one of those stupid tropes that have gained currency among the sort of people who value cleverness over wisdom. It sounds great and is routinely trotted out to smack down anybody who argues for things like the existence of God or the reality of a miracle.
There’s only one problem: it’s meaningless crap.
There is no sliding evidentiary scale whereby claims of factuality require more and more astounding evidence until the biggest claim of all requires and infinite amount of stupefyingly awesome evidence to establish the claim. We do not require a tiny amount of evidence for petty theft, but virtually incredible evidence for murder.
What we requires is sufficient evidence. Produce the purloined necklace from the suspect’s pocket with his prints on it and that’s enough. Produce the corpse with the bullet from the .45 belonging to the suspect, give motive, and demonstrate that he was seen by witnesses shooting the guy and you’ve got a conviction. Nobody says, “The charge of murder is more extraordinary than the charge of petty theft, so in addition to this normal evidence we will need something extraordinary.”
All this stupid meme really means is “I dislike claims of the supernatural, so I’m going to lard on a bunch of unreasonable demands in order to make fend off the obvious evidence. Is there a documented medical miracle? I won’t pay attention to the evidence. Instead, I will demand to have such miracles occur in a laboratory (even though I would never demand that all murders and thefts occur in laboratories). If the evidence is overwhelming that the miracle, say “giving the gift of sight to a woman who had no pupils in her eyes“, took place, I will demand to know why the miracle does not occur to *everybody* and why all blind people are not healed.
“Incredible claims require incredible evidence,” can only mean, “claims that I choose to reject willfully and a priori require evidence that I will not choose to reject willfully and a priori.” This is entirely a matter of the speaker’s intellectual and volitional dispositions. But a speaker’s intellectual and volitional dispositions have no effect on the truth, i.e. the reality, of a claim. Thus the the idea that, “incredible claims require incredible evidence,” is not relevant to judging the truth or falsity, i.e. the reality or non-reality, of any particular claim.
Remember: theists are people who fear the light of rational inquiry, while atheists are Thinking People who fearlessly follow the evidence wherever it leads. Fortunately, it leads to the conclusion that we live in a godless universe that they arrived at when they were nine years old and they have never ever had to stop and reconsider that mystical insight. They’re so right they don’t even have to bother with counter-evidence.