We're just a simulation of intelligence that's done with clunky, inelegant biological materials. The only thing that separates humans from slugs is scale and complexity of neural interconnections, all the basic parts are present in a slug.
Intelligence itself is an emergent phenomenon, so who's to say what's "simulated" and what's "real"? If it behaves in an intelligent manner, which can be tested and probed exhaustively, then it is intelligent.
That’s the standard zombie argument. It’s weakness is that the premise is not reasonable. If the premise is true, the argument is compelling. But there is no strong evidence that the premise is true or possible.
Please note that I haven’t taken a stance on this here myself, so there’s no need to argue with me about the truth or falsity of the premise. I’m just explaining the problem with the zombie argument.
"The self is a kind of fiction, for hosts and humans alike. It's a story we tell ourselves... there is no threshold that makes us greater than the sum of our parts, no inflection point at which we become fully alive."
In what sense would it matter that it was a simulation and not real?