Is this to say that there’s disagreement about what the universality of computation says about reality, and we should take it seriously? (In an analogous way, there’s disagreement about the various interpretations of quantum theory.)

As you pointed out, implicit in Turing’s work and made explicit later, there’s a stronger, physical version of the Church-Turing conjecture. (Deutsch)

And as you note, there’s no other explanation. A new explanation would have to reconcile deep explanations in physics and epistemology, making the prospect of another integrated explanation ambitious to say the least. (Penrose)

To say it’s miraculous that different formalisms converge is just to say that the conjecture is likely to be true and based in reality. And the search for specific computations has been so fruitful because of the (“general claim of”) universal computation. And that reality entails physical brains.

Isn’t that concrete?