I have looked into this somewhat deeply and he might have a point, but it's a bit subtle. First, current computers are not powerful enough to show him wrong. Second, the Many Worlds interpretation of QM is both deterministic and quantum, and since Jurgen is assuming his super-program creates a multiverse anyway, it's a logical next step.

The meat of Jurgen's proposal is that "fast" programs are more likely (which makes sense, IMHO) and quantum universes are too wasteful computationally (which seems less obvious).

If you want to read more along these lines, I can recommend something quite interesting from last year. It references Jurgen but argues that computational speed doesn't matter, only the length of the algorithm needed to produce our subjective experiences:

Could the physical world be emergent instead of fundamental, and why should we ask? (short version) by Markus P. Mueller https://arxiv.org/abs/1712.01816

Whether or not the universe is deterministic, quantum computers will work as long as nature works by wavefunctions and unitary matrices. There are many good reasons for believing this to be true, including experiments. Real randomness is not a requirement.

Schmidhuber doesn't seem to be a physicist, so I'll go with the majority of physicists on this one. Currently there is no reason to assume that quantum computers are impossible. There might be engineering challenges that we can't overcome, but quantum mechanics is a decently well established field and unless its assumptions are fundamentally wrong, quantum computers should work.

Sounds like a crackpot to be honest. QC doesn't work yet because of practical limitations, but individual blocks have been shown to work separately and even small computers [1]. In looking at his wording he may be addressing a straw man, because QC has never aimed to be a general purpose general computer.

The universe is usually thought of as not deterministic. The deterministic interpretations out there come with huge problems: non-locality. Basically, that all particles in the universe are connected with a wave of sorts that acts instantaneously no matter the distance. But this is a philosophical distinction at best. Quantum computers work just fine.

[1]https://www.technologyreview.com/s/609451/ibm-raises-the-bar...

Hint: "There is no physical evidence to the contrary" isn't really a proof.

You are getting down-voted because you are shifting the burden of proof.

It wasn't me that was shifting the burden of proof!

It was the original quote from Schmidhuber, claiming as if it were a known fact "The universe is deterministic, and the most efficient program that computes its entire history is short and fast", backed by the (arguable) argument "There is no physical evidence to the contrary."