> What do you mean by 'supernatural'

I would just say something outside our current capacity for understanding. How does that quote go...something like "sufficiently advanced technology is indistinguishable from magic". "Not detectable by any measurement" isn't right because we clearly detect it in some way since we are discussing it now.

> Feeling that there 'must be' a soul is not enough to prove that it exists.

We don't have any proof that consciousness is part of the brain and is produced by it either. We also can't even prove other people are conscious besides ourselves. In this domain the idea of "proof" becomes less relevant.

In a simulation of a storm, does anything get wet? In a simulation of a mind, is there a real conscious? A real soul? Or just a simulation of one?

My guess is our brains act as a receiver for some "field" of consciousness. Of course it's just a guess, same as yours or anybody else's conceptions of consciousness and the spiritual world.