That view states, as you describe, that somehow the whole is more than just the sum of the parts. I reject that. Instead, my claim is that if the only parts you have are physical parts, you will not get consciousness. You need other parts too -- specifically, mental/consciousness parts.
(although, this sounds closer to a dualist view, while my view is more idealist)
> If you fully understood the laws of physics at an atomic level, would it be sufficient to recognize a cpu as turing complete if you see one?
This is testable if you take an alternate universe with very few laws. Somewhat canonically, do you understand a Turing machine built in Conway's Game of Life if you understand the 2 rules of that game. (Or 4 rules, depending on how you count).
The only way to understand it is to play the game.
It's a debatable position in philosophy against the reductionism OP is describing, and maybe a bit magical but I'd find it the more interesting of the two positions to hold.