Distinguishing between virtual reality and reality:
It’s hard because there’s no way to be truly objective from a non-human perspective.
Through education it’s quite possible for there to be not a single human on the planet nor any bit of written history to indicate a difference between a virtual reality and reality.
It’s nice to believe that there’s a special class of people with special methods that can break free of delusion entirely and see “only the truth” but that’s absurd; we’re still all human and the best of methodologies will suffer from bias we can’t even see, because there’s no non-human objectivity possible just yet.
Until then, we just have to hope for no mass delusions going on at present that none of us can see or measure. Then again, we’ll never know.
So, we have to work with the limitations that we have for now and hope we’re doing it right.