Fundamentalists are fond of responding to claims about evolution (dinosaurs, etc.) with, "Were you there? How could you know if you were not there?" This is even taught as a rhetorical tactic in fundamentalist elementary schools (which I'm embarrassed to be an American for admitting they exist here).

This seems to be an approach similar to what you're taking here, except you put an interesting twist on it by handwaving your appeal to spooks with stuff about "the unknown" and then claiming it is the more rational position. Once again: we know, as certainly as we can know anything, that the mind cannot function without the body functioning. Therefore, the idea that there is no experience after body death is a more rational position to take than anything involving 72 virgins, nirvana, reincarnation, or blah blah Bible Jesus magic.

The difference is that we know the fundamentalists are wrong because their beliefs solidly run up against known facts. I am suggesting that filling the gaps one way (even though it feels more rational) is as irrational as filling the gaps any other way.

And we know very little about the mind. We know a lot about the brain. As far as the exact links between mind and brain, that is still quite a bit up in the air.

We know the mind exists as a phenomenon of the body's operation. No operating body... no mind. We have plenty of evidence to support this and zero evidence to the contrary, even if we may not have all the details, so your attempts to rescue a spook reality of disembodied minds by furiously waving your hands and going "it's all unknown!" is disingenuous.