I’d say even simply a simulated physical environment could be good enough to be indistinguishable. As Morpheus put it:
What is real? How do you define ‘real’? If you’re talking about what you can feel, what you can smell, what you can taste and see, then ‘real’ is simply electrical signals interpreted by your brain.
Of course, that would require insane amounts of compute, but so would a brain upload in the first place anyway.
I’d say even simply a simulated physical environment could be good enough to be indistinguishable. As Morpheus put it:
Of course, that would require insane amounts of compute, but so would a brain upload in the first place anyway.