Another way of putting it: you can’t possibly know that there isn’t some device out in the universe that lets you do more powerful things than your model (eg. a device that can tell you whether an arbitrary Turing machine halts), so it can never be proven that your model captures real-world computability.
Another way of putting it: you can’t possibly know that there isn’t some device out in the universe that lets you do more powerful things than your model (eg. a device that can tell you whether an arbitrary Turing machine halts), so it can never be proven that your model captures real-world computability.
Be careful stating what physics can’t prove.
Fwiw, I disagree with the frame of that post as well.
I’m happy to agree that you can prove that your model captures real-world computability under a particular formalization of physics.