alt Hacker NewsAssuming you don't believe humans have any metaphysical component, then the only remaining question is whether there's some essential component to being human that depends on impossible-to-precisely-simulate portions of reality. Nothing we currently know of biology suggests that that would be true, as much as it continues being pursued by people who need there to be something mysterious about consciousness or brains.
In any case, a closely-but-not-perfectly-accurate simulation of a real human brain is still going to be human, unless you believe that someone becomes less human when they're experiencing some kind of cognitive decline, or a stroke, or other biological malfunctions. The point is, there is nothing essential to the having of a physical brain that creates the concept of consciousness or sense-of-self.
How can a simulation be human when it isn't human? It's a simulation. A human is a human, a simulation is not. Anything that is not a human, is not a human and can never be a human.
And there absolutely is something essential to the concept of being human that we are entirely incapable of replicating artificially. In fact as far as I know we are incapable of synthesizing any kind of life whatsoever. We can't even create the simplest type of living cell imaginable.
So to claim that we could just create consciousness, a fundamental property of this "life" thing that we don't properly understand, within a piece of rock is beyond naive. We don't even know what it is or how it is.