[Vi0]

In order: There certainly could be. How would we know? What if the universe isn't deterministic? Certainly it's more pragmatic to assume that only what we can experience is real, but that doesn't make it true.

The belief that there could exist parts of reality that the scientific method can't explain does not require having specific examples.

Even if all of reality can be understood by physics, that doesn't mean it can be simulated.

If physical reality can be simulated, then you could simulate the physical reality that makes up a person.

There is no guarantee that your simulation of the physical reality of a person would respond identically to an actual person.

There's a large body of philosophy on this, but basically it comes down to life working out better if we all assume everyone else is conscious.

There probably can be two similar beings demonstrating identical behavior with only one being conscious. Depends on what you define consciousness as I imagine.

I happen to lean towards believing Science can explain reality and that consciousness is a physical phenomenon, but to claim that things categorically must be that way is unfounded.