Deutsch defends Many-Worlds Theory

New podcast: The Multiverse is REAL - David Deutsch.

He says the double-slit experiment conclusively proves the many-worlds theory. He accepts the parallel worlds for the same reason he accepts the existence of dinosaurs (millions of years ago). It is the only way to explain the evidence.

He admits that the photons are not really particles, and that any waves show a similar diffraction pattern. But he says that for the photon to behave as a wave, it must exist in multiple copies.

He also admits that all this has been known for decades, and yet most physicists do not accept this argument for many-worlds.

I do not see any merit to this argument. The double-slit experiment only proves that light, and other beams like electron beams, have wave properties. That's all. It is not even evidence for quantum mechanics, as this wave explanation was accepted before quantum mechanics was invented.

When asked about alternative theories, he says the von Neumann had this crazy idea that if you observe an electron in one place, then the possibility of it being somewhere else ceases to exist.

I do not see the problem with that. I do not even think the issue has anything to do with quantum mechanics. Anytime you estimate the probability of an event, and then observe it, that means that the other possibilities did not happen. That is how probabilities work.

He pushes quantum computing, but admits that he has not followed the latest technology.

I see the argument for many-worlds as nothing more than a rejection of probability theory. You could take any scientific theory that predicts probabilities, deny that the probabilities make any sense, and conclude that there are parallel worlds of unobserved possibilities.

That is all many-worlds theory is. I don't think that it even has anything to with quantum mechanics. It is only expressed in terms of quantum mechanics, because textbook QM emphasizes the probabilities. But other theories use probabilities the same way, and could have many-worlds interpretations.

Many-worlds thsoey is just the same as taking a science textbook, announcing some philosophical disagreement with probability theory, and redacting all the sections mentioning probability. It adds nothing. It just removes the theory's predictive power.

It is hard to see how any intelligent man takes many-worlds seriously. It offers nothing. Maybe they just don't understand probability theory, as I do not see anywhere that they recognize that they are just rejecting probability.

PBS TV has a news item:

How quantum computing could help us understand more about the universe

Scientists, researchers and some big companies are eager to jumpstart the next generation of computing, one that will be far more sophisticated and dependent on understanding the subatomic nature of the universe. But as science correspondent Miles O’Brien reports, it’s a huge challenge to take this new quantum leap forward.

A lot of hype. They admit that a fault tolerant quantum computer might be decade away. No one admits that it might be impossible.