tallg, good so you beleive that. I also beleive it but right now the science can not give a solid proof to explain all the mechanisms how the brain works, but even that we beleive it.
now, if I asked this question to one guy hundreds years ago, what he could answer, probably he could not beleive it bcoz the science was not developed like nowadays.

the humain instinct is that we beleive on what we see with our eyes and hear with ears.