Isn't this assuming that quantum computers become a reality? The last I heard, nobody could prove conclusively whether their putative quantum computer was actually using quantum effects.

To me this argument is like saying, "Science shows that cold fusion could certainly provide the energy needed for an antigravity machine".

I'm not qualified to say whether that middle inductive step with this Church-Turing-Deutsch principle really holds or not, but I do know that neither quantum computing nor consciousness are well-understood, rigorously defined things.

No, it actually has nothing to do with quantum computing specifically, it applies for classical tape-based Turing machines (or an x86 with unbounded time and memory). It basically says “anything physical is computable.”

Not according to that wikipedia link:

> He observed that classical physics, which makes use of the concept of real numbers, cannot be simulated by a Turing machine, which can only represent computable reals. Deutsch proposed that quantum computers may actually obey the CTD principle, assuming that the laws of quantum physics can completely describe every physical process.

Deutsch was mistaken, at least on that specific issue of the uncomputable reals being a fundamental limitation on Turing machines doing physics: https://michaelnielsen.org/blog/interesting-problems-the-chu... It’s also incidental to the overall discussion, Deutsch was simply postulating about a limitation in Turing machines (in the same way that deterministic finite automata are fundamentally limited in the class of problems they can solve).

I don’t necessarily feel like arguing further about this tiny issue, or a distraction about your misconceptions regarding quantum computing[1]; this problem has been widely discussed since Deutsch and there are plenty of sources out there. The point is that it takes a huge cognitive leap to suggest that consciousness is either fundamentally spiritual, or part of a (hypothetical) class of physics problems that can’t be solved by a computer.

[1] Quantum computers are real. You are confused by news stories about private companies with outlandish claims of powerful quantum computers. In physics laboratories, small quantum computers have existed for a few decades. Typically they are too small to do anything useful (I saw one in person that could factor any positive integer... if it was less than 15).

It's important to note that you don't need to be able to simulate "consciousness" (raw feels, philosophically contentious, who knows what it's made of) to get "intelligence" (by which I mean powerful optimizing behaviour in a wide variety of environments).

It may or may not be the case that anything intelligent enough necessarily becomes conscious anyway, but there's no way that intrinsic difficulties with simulating "consciousness" could block us from getting intelligent behaviour.

It's not really unexplored. See Chris Koch.