I think the author is misunderstanding the XKCD comic about rocks [1] (or maybe I am). Just because it's possible to run a simulation of the universe on rocks,

I think the author is misunderstanding the XKCD comic about rocks [1] (or maybe I am). Just because it's possible to run a simulation of the universe on rocks, doesn't mean that rocks are conscious or turing complete. You can't forget about the person who is manipulating the rocks. The system as a whole is turing complete. Likewise with the bar of iron example that the author gave, you can't forget about the person interpreting the atoms in the bar of iron. The system as a whole is turing complete (and also naturally conscious, because the person doing the interpretation is conscious). And there is nothing physical necessary to represent such systems. You can simulate turing complete systems inside turing complete systems [2]. So I don't see why consciousness has to be a "physical phenomenon" as the author claims. [1]: https://xkcd.com/505/ https://xkcd.com/505/ [2]: https://youtu.be/xP5-iIeKXE8 https://youtu.be/xP5-iIeKXE8