Facing Reality is an Ugly Scar

To see how foolish the many-worlds theory (MWI) is, just read what the advocates say.

Lev Vaidman just posted The many-worlds view of quantum mechanics:

My explanation has two very different parts.

i) The ontology, stuff that exists, including laws constraining possible states of stuff and dynamical laws of time evolution of stuff.

ii) The prescription of correspondence of the state of stuff with our experiences which we inquire through our sensory organs, sometimes equipped with instruments like telescopes, microscopes, sonars, etc.

The ontology is all the parallel universes. But relating the theory to our experiences in part (ii) is impossible without probability, and that is rejected, so he settles for a theory that does not relate to our experiences.

In conclusion, physics explains all phenomena we observe on Earth extremely well. Collapse of a quantum state at measurement is an ugly scar on a beautiful quantum mechanics. The only role of the collapse is to avoid parallel worlds which anyway are not supposed to be seen according to the theory. Without collapse we have to accept MWI. Apart from the disappointment in understanding that I am not a unique Lev Vaidman, and that there are multiple copies of me in other worlds, MWI allows me to believe that by and large I understand how the universe works. For me, parallel worlds are not a too high price to pay for understanding Nature.

So he says the collapse is just a way of avoiding the parallel worlds that we never see anyway. I call that facing reality, but he says it is an ugly scar.

He acts as if the collapse is peculiar to quantum mechanics, but it is not. All scientific theories do something similar when a prediction is compared to a measurement. The Bayesians call it adjusting their priors.

So what does he get from having of other worlds that cannot be seen? It allows him to believe that he understands Nature!

The many-worlders complain bitterly about the collapse being part of quantum theory, but it is very much part of many-worlds theory also. Instead of calling it collapse, they call it world-splitting. Instead of collapsing the wavefunction so that it better describes our universe, they say that the wavefunction decomposes into pieces where one piece describes our universe, and other pieces describe unobservable parallel universes.

The MWI does not solve the measurement problem, or explain the collapse/splitting, or do anything useful.

This is not Physics, and not science. It is too stupid for a rebuttal. There is not any substance to the theory. I would not even bother commenting on this nonsense, except that a great many of our leading physicists and physics expositors buy into it.

Broadly speaking, science consists of making observations, formulating theories, making prediction probabilities, and then making measurements to reconcile theory with experiment.

Many-worlds theory says to skip the last two steps. It denies that prediction probabilities make any sense, and it says that reconciling with experiment is an ugly scar that just rules out invisible parallel worlds. It is impossible to believe in many-worlds and have a scientific world view. For this reason, I doubt anything from Sean M. Carroll, Max Tegmark, and Leonard Susskind, even though they are all brilliant and explain some things very well.