Actually, I hate to let him off the hook, but he doesn't have to "provide a burden of proof." That's not a proper use of the phrase "burden of proof." It means, essentially, "the responsibility to prove," not "a mass of evidence."surreptitious57 wrote: You have to provide a burden of proof regardless of anything else
And so whether another person makes a claim is of zero relevance
And one has no "burden to prove" unless one makes such a claim as, " X does not exist." If that's his claim, then yes, he has a burden of proof, as you say. If his claim is only "[I don't know if] X exists," then he's only making a claim about the limitations of his personal experience, and meets the burden of proof merely by making a truthful claim in that regard: we would never know what his experience was, so we'd have to take on faith that he was truly reporting his internal state.