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Many World Interpretation and Personal Choice

  1. Dec 7, 2014 #1
    So I've heard of the many worlds interpretation - something about any event that could have happened in the past, really did happen in some parallel universe.

    What I want to know is - how does this translate into personal choice?

    Like, say I am considering some decision. Tonight for dinner I will eat either chicken or fish. Does the universe branch out into a significant portion in which I choose chicken, a significant portion in which I choose fish, and a significant portion where both or neither happen, or is this not really how it work? Are most (>99%) of the universes going to have me choosing, say, the chicken regardless, and only a small portion where something else happens? I mean, obviously if I throw a ball through the air, in most of the universes, it is going to follow a well defined path, assuming nothing interferes with it. Is a human choice a similar event to this? i.e. one that is fairly certain to follow a well defined path, or is there something about the complexity and electrical pulses of the brain, or our unified field of consciousness, that makes humans not like this?

    I think quantum uncertainty might be related to this? Like, the way an electron moves might be uncertain. But the way the ball moves is basically certain. Does quantum uncertainty apply to lifeforms, so that their actions too could not ever be mostly predicted (perhaps due to the working together of tiny parts in the brain like neurons and electricity, I'm not entirely sure what the mechanism would be), or are they predetermined to a high degree like the ball is?
  2. jcsd
  3. Dec 7, 2014 #2


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    Staff: Mentor

    If you prefer chicken over fish that strongly, yes, that's what the MWI says is going on.

    You may want to get hold of a book entitled "Where does the weirdness go". It gives a pretty decent non-technical introduction to the reasons why macroscopic objects like thrown balls do not display quantum weirdness even though they are made up of quantum particles which do.

    As for where consciousness and free will come from, and whether quantum uncertainty has anything to do with it? No one knows. There's some fascinating speculation on this subject and while much of it is garbage, some of it is accompanied by well-thought-out technical arguments and worth reading if you're interested. However, you should be aware that:
    A) this entire area is highly speculative and controversial. There's very little that's generally accepted and even less that has been (or even can be) experimentally tested.
    B) you need a fairly solid grounding in quantum mechanics to even get started.
    Last edited: Dec 7, 2014
  4. Dec 7, 2014 #3
    So... no one knows if humans/other lifeforms display quantum weirdness?

    They don't prefer chicken to fish. Let's say they tend to eat each equally. But let's say, that in our world, it turned out that a sequence of events led them to choosing chicken. They deliberated over it, maybe flipped a coin. Is this sequence of events going to be determined?

    Is the basic reason why macroscopic don't display quantum weirdness because the effects "average out"? That's how I reason it, but I guess I should have a look at this book because that's probably wrong and a simplistic way of looking at it.

    So, no one knows if quantum weirdness applies to the human brain? It's not known whether the brain acts like a macroscopic object, or if it's possible that the quantum effects don't "average" out but may grow chaotically, or something like that?
  5. Dec 7, 2014 #4


    Staff: Mentor

    That's a misleading interpretation of what was said.

    Of course quantum 'weirdness' (meaning the laws of QM) applies to the brain as it does for every object out there. The brain is a macroscopic object - its not like a macroscopic object - it is a macroscopic object.

    What is not known is if the phenomena of conciousness depends fundamentally on QM or is simply an emergent phenomena like most of what we see around us.

    For example liquid helium is a macroscopic object but its weird behaviour depends strongly on QM. Its not known if conciousness, free will etc is like that or not.

    Last edited: Dec 7, 2014
  6. Dec 7, 2014 #5


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    Staff: Mentor

    No one knows if it has anything to do with consciousness - as Bhobba says above, there's no doubt that the brain is as subject to the laws of physics as everything else, but that doesn't necessarily tell us anything about consciousness or free will.

    Somewhat against my better judgement, I'll refer you to Penrose's "The Emperor's New Mind". It's a good read as long as you keep your skepticism defenses on full alert - as I said above, this is all very speculative. Also be aware that when I said "you need a fairly solid grounding in quantum mechanics to even get started", that was a polite way of saying that if you start theorizing before you've acquired that solid grounding, you will just make yourself look ridiculous.

    You could also give Daniel Dennett's "Consciousness Explained" a try. The title promises rather more than the book delivers, but it raises many of the issues that any explanation of consciousness as physical phenomenon must cover.

    And with that said, I'm going to close this thread. It's a fascinating topic, but it's also moving out of scope for Physics Forums.
    Last edited: Dec 7, 2014
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