Reality, Perception of Reality, Machinery

A condition called Dissociative Identity Disorder may help to unpack this thing we call reality.

Different "alters" do indeed perceive the world in very different ways; same brain just different ways of being/perceiving/activation.
Mind-boggling, but a sighted person simply did not have brain activity associated with sight when a blind alter was in control.
As you might suspect, philosophers in searching for clarity in what is going on and how to talk about it, have proposed different views on what is happening:

https://blogs.scientificamerican.com...nd-everything/

It's DPD (P for personality). Philosophical questions are always fun, ; perception is how fast information reaches us, what if we are in a machine that goes faster than said perception, does reality change then. Don't think so