LDeer

Damn is this a good philosophical question. However, my response is related back to good ol' religion, specifically Christianity, or anything which has no credible explanation yet is widely believed(such as free will). If you don't know if God(or in this case, you being a brain) exists or is real, and can never prove nor disprove this statement, then both sides are true(philosophically speaking). Like Schrodinger said in his Schrodinger's Cat paradox, if you can never find any evidence that something is either real or not real, then it is in a perpetual state of being both sides of the argument.

So, the moral of the story is, you can't really trust your senses, only your belief.

That's just my two cents, I'm sure it doesn't really make much sense, or is wrong.