Well, I think the "brain as an antenna" theory is also plausible given your preconditions.

But I think my issue with the emergence theory is that it seems to imply to me that consciousness is non-physical and non-local. So what entity is actually experiencing the consciousness? It's not that I believe consciousness is physical and local, but people who make the emergence argument seem to believe it is and I can't figure out how that is supposed to work.