Monday, February 22, 2021

The main weaknesses of Many-Worlds theory

A new short video, Tim Maudlin - Many Worlds of Quantum Theory, was posted. A philosopher of science comments, and was surprisingly sensible.

He refuses to dismiss Many-Worlds theory because it seems like nonsense. Okay, fair enough.

He does point out that probabilities make no sense in the theory. You might think that a probable event is one that occurs in most of the worlds, but the proponents of Many-Worlds adamantly deny that.

I don't think most people appreciate what a devastating critique this is. A lot of smart people take Many-Worlds seriously, so you would think that they have some explanation for probabilities, but they really don't. They have no way to make sense out of the idea that some events are more probable than others. They just give up on the concept.

Giving up on probability means giving up on the whole scientific enterprise. What is science, if not to predict some events as being more probable than others?

Just to repeat, Many-Worlds theory is worthless because it is unable to ever say that one event is any more probable than any other.

Maudlin also explains that decoherence does not solve the measurement problem that bugged Schroedinger and others. Wasn't that the main point of Many-Worlds theory? If the theory does not do that, then what is the point?

Supposedly the Copenhagen Interpretation of quantum mechanics is deficient because it does not explain how the wave function collapses when a measurement is made. The Many-Worlds theory says that the wave function never really collapses, but appears to collapse because of interaction with the observer's wave function and decoherence. The other possible outcomes show up as parallel universes. The Many-Worlds advocates say we need to accept the parallel universes in order to correct this Copenhagen deficiency. But they don't solve the measurement problem anyway.

So Maudlin destroys Many-Worlds in about 5 minutes. But being a good philosopher, he does not reject it. Believe it if you want. Philosophers say it is just fine to believe in theories that have no theoretical advantages or practical utility.

1 comment:

  1. Roger,
    I'm quite uncertain what they think they are even calculating because they can't even count much less observe "The other possible outcomes show up as parallel universes".

    If you pull a marble out of a bag, in order to calculate a probability of anything particular you must first know how many marbles are in the bag, what colors they are, etc. If this information is not known, you can not calculate anything. Of course you can always pull some bullshit out of hat, but that isn't a calculation, that is a blind speculation (making stuff up).

    Probability isn't and never has been reality, it's a calculation performed on numbers only. Once again, if physicists don't draw this distinction (because they have never understood what the words actually mean) it won't matter what they calculate because they can't draw a distinction between abstraction and actuality. Never take advice of any kind from someone who can't make this distinction.

    Doing math does not inform reality anymore than wishing beggars produces horses.