Just read this and tell me what you think.

[Esquilax]

The effects we try to describe is a result of how our brain processes the observations we make. If the brain processes in another way the observations are now different.

Mhmm. And there are at least a few gravestones out there for people who have observed that gravity doesn't work on them and they can fly, generally right out of windows, downward, at a terminal rate of velocity. Almost as if gravity does work on them, regardless of their observations of it...

By the way, there were also plenty of other people whose brains were processing correctly, who witnessed gravity working on those people. We don't make our observations in a vacuum, you know; there are other people continually reverifying our observations as consistent with their own. In fact, that's the main way we diagnose mental illness, is seeing how a person's model of reality deviates from the commonly observed standard.

Mind you, none of what you've said has even come close to answering the question you were asked, which was what our ability to alter our perceptions has to do with an afterlife. If your point was just that we base our lack of belief in an afterlife based on our observations, and our observations can be altered, so ha ha, you don't know, you have faith, then you're just committing an argument from ignorance.