The Least Parsimonious Theory Ever

Here is a podcast interview with the leading advocate of many-worlds theory:

Do We Exist in Multiple Realities? David Deutsch and Sam Harris on Quantum Physics

Sam Harris speaks with David Deutsch about quantum physics and current events. They discuss the “many-worlds” interpretation of QM, Schrödinger’s cat, constructor theory, quantum computing and whether it will ever be practically possible, recent developments in AI, the prospects of artificial super-intelligence, the alignment problem, antisemitism and the historical persecution of Jews, misconceptions about Israel, the future of the Jews in Israel and the West, and other topics.

David Deutsch is a visiting professor of physics at the Centre for Quantum Computation at Oxford University, and an honorary fellow of Wolfson College, Oxford. He works on fundamental issues in physics, particularly the quantum theory of computation and information, and constructor theory.

He has written two books, The Fabric of Reality and The Beginning of Infinity, aimed at the general reader.

Deutsch starts by saying that it is not an "interpretation" of quantum mechanics. I agree with that, although for different reasons. He says that saying many-worlds is an alternate interpretation of quantum mechanics is like saying dinosaur theory is an alternate interpretation of Bible Genesis. We do not see the parallel worlds, but we do not see the dinosaurs either. Funny argument.

He wrote a whole book about his supposedly scientific worldview. I think his views are bizarre.

Harris asks:

I 16:42 must admit 16:43 this at first glance and perhaps even at 16:47 second glance seems like the least 16:50 parsimonious theory uh ever 16:54 proffered and we we we seem to be. at 16:57 least we imagine we're in the parsimony 16:59 business in science how how is it that 17:02 this is acceptable this idea. that I mean 17:06 is does this can this be summarized by 17:09 saying 17:10 that everything that can happen does 17:14 happen.

There is no good answer. Nor is there any good answer to Harris pointing out that the theory says that there are copies of Deutsch is parallel universes arguing the opposite.

Harris assumes, as most people do, that if the theory predicts a lot of bizarre things that are never seen, then those things must be very low probability. But that is incorrect.

[Harris] while there's no such 18:20 thing really as possibility everything 18:21 everything that can happen does happen 18:24 it doesn't happen the same number of 18:25 times so there's kind of like a 18:27 frequency difference across the the 18:29 multiverse.

[Deutsch] yes uh it turns out that 18:32 frequency is not good enough to to 18:34 support the notion of probability that 18:37 we need in physics and in everyday life.

That's right, they cannot say that they are low probability, the way that term is understood in math and physics and everyday life. He goes on to explain that he has developed some other sense in which the bizarre events can be rationalized away. That is, you can think of the bizarre events as low probability, even though they are not as we understand probability.

Sean M. Carroll gives a similar explanation, and I don't think that either one makes any sense. But listen for yourself.