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Parallel universes almost certainly do not exist

  1. Jul 10, 2004 #1
    I came up with this reasoning last week, and I've been looking forward to posting this here since then. Okay, supposedly parallel universes are created when a choice is made, such as Milk or Tea, Answer the phone or Don't answer the phone, and Post this in the forums or Don't post this in the forums. Right now I am consciously making the choice not to jump up out of my chair. And now. And now. And now. And now. And on and on and on; you get the idea. Why then do we always end up in the universe where I make the logical choice, i.e., not to jump out of my chair? Probability dictates that it is very likely that I end up in a universe where I jumped out of my chair at least once, given all the decisions whether or not to jump that I made. But anyone would have predicted that I would just stay seated, ans they would have been right. You could try to explain it away with the weak anthropic principle, i.e. that we ended up in the universe of no jumps because it exists and someone has to occupy it, but I don't think that would satisfy anyone. Why do we live in a universe where people don't randomly shout, don't randomly wave their arms, don't randomly jump up, and do consistently make the logical decision?
  2. jcsd
  3. Jul 10, 2004 #2
    You're right. The theory was pretty crazy to begin with and it will probably be terminated very quickly.

    I believe something was said about this topic in M. Kaku's book "Hyperspace" (stating that it should be dismissed as other/better theories come along).
    Last edited: Jul 10, 2004
  4. Jul 10, 2004 #3
    That is a very interesting point.

    However, consider the following take on that same idea:

    In considering human behavior, you have to take into account that the choices we make are governed by conscious decision, at least macroscopically. A person’s choice to sit and act rationally will be highly influenced by the long string of rational decisions that led them to their current position in ‘parallel universe space’. If a particular person has made a long series of rational decisions to sit and act normally, then the probability of them suddenly jumping up and acting irrational will be extremely low. The more rational decisions your particular history reflects, the higher the probability that this behavior will continue. Society even influences these choices and molds the choices to be rational on average as the individual grows in age, decreasing the probability of a sudden irrational act. Society also acts on people en masse, affecting the distribution of these probabilities over time, decreasing the overall distribution of probabilities for irrational acts even further.

    The probability of the sudden irrational act, and indeed all possible acts, is still there, just extremely low compared to the probability of the rational act in accordance to the history of individual, and the history of all individuals interacting together. The parallel universe in which you suddenly jump up and shout still exists, but in that universe the probability of any number of people doing that as well has the same overall low distribution. Any one universe would only be witness to a very few events of this type.

    For an example, simply read the news. There are always seemingly sane people who suddenly engage in irrational acts. These events just happen at a very low frequency in the particular parallel universe in which you are currently residing and reading these words, and indeed in all universes on average.

    There is, of course, a universe in which you reside that reflects a different history and the probability of your irrational acts is much higher than your rational ones. However, that universe would contain the same average spread of individuals and your actions would cause you to be the exception there rather than the norm.

    As a matter of fact, now that I have typed this and you have read it… our universes have diverged. In my current universe space, you jumped up suddenly from your chair for no obvious reason while the majority of people remained seated. This point of divergence will surely alter your probability distribution in regards to making rational decisions in the future, while the rest of us have just yet another rational choice reflected in our histories.

    That being said, I don’t necessarily believe the many-worlds interpretation of quantum mechanics, and neither do I disbelieve it. It is interesting, intriguing, useful for philosophical discussion, but ultimately impossible to prove or disprove. An argument can always be made from an opposing viewpoint just by widening the view to allow a counterpoint. There is no hypothetical limit to the amount of justifications that can be included in the arguments since it is a completely abstract concept.
  5. Jul 11, 2004 #4
    From what I understand, parallel universes do not give a darn about probability and obey only possibility. It's true that it's not very probable that I will suddenly jump up after not jumping up 10 times, but it is very possible that I might change my mind the eleventh time. But consider the probability that I will end up in a universe where I jump at least once when I make a choice to jump or not 100 times. On the first decision, the universe splits into two parallel universes. On the second decision, both twin universes split into two, thereby creating four. On the third decision, the universes split into eight. With each iteration, the number of universes doubles. After the 100th decision, there are 2^100 universes, or 1267650600000000000000000000000. Only one of those universes corresponds to my never jumping. If a conscious decision is required to create parallel universes, I will dismiss that technicality by now making a conscious decision 100 times to jump or not to jump. As you probably predicted, I did not jump at all. The odds of my landing in a universe where I don't jump were beyond astronomical, but it was obvious to anyone with common sense that I wouldn't suddenly jump. I know that there are the same immense odds if you take each individual universe seperately. For instance, if you buy a lottery ticket and it is or isn't a winner, you could get all excited and shout "Wow! The odds of my getting this exact physical ticket were extremely low! In fact, they were the same odds as getting the exact winning ticket!" What makes getting a winning ticket so special (besides the payoff, of course) is that there are so many non-winning tickets. The odds of your getting any specific ticket are very low, but the odds of your getting a losing ticket are very high. Likewise, the odds of getting any specific universe are very low, but the odds of getting a universe with at least one jump are ridiculously high.
  6. Jul 11, 2004 #5
    I think generally the analogy of us making choices for multiple universes is irrelovent the p universe or many worlds theory doesn't say new universes are made when WE make choices it is when "choices" are made at the quantum level-- which is very different from decideing whether or not to drink tea or milk. I think you may have took the analogy too far. However this is only my reasoning someone feel free to correct me.
  7. Jul 11, 2004 #6


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    Not that hard, as I see it. Parallel universes can be cut out of the equation by Occam's razor. No observable consequences to this universe = irrelevancy. The cosmic version of the no harm, no foul rule.
  8. Jul 12, 2004 #7
    The analogy holds when you consider that you are making your observations from the viewpoint of a universe that has already had an infinitely large number of rational choices reflected in its history. In any other kind of universe, of which the theory holds also exists, not only would you not have jumped, you probably don't exist at all.

    The universe in which humans evolved to consider these questions is already constrained by a history of rational events. Possibility and probability are two different animals. All events, irrational and rational, are certainly possible and, by the many-worlds interpretation must exist, but the probability distribution of of rational vs irrational events in the particular universes in which we exist is not equal. The probability of rational events, by necessity of the history of these universes, is far greater than the probability of irrational events. In some infinite number of universes it would be the other way around, and in an equally infinite of others it may be exactly equal.

    As for extending a quantum mechanical idea to a macroscopic universe: the many-worlds interpretation isn't confined to microscopic interactions, the poor eternally-confined cat wishes it was. Quantum choices can have direct macroscopic effects.

    The many-worlds approach seems to be alive and well, resisting both proof and disproof with equal vigor. Either way, it is an interesting approach with interesting consequences... useful for pondering on a rainy afternoon.
  9. Jul 12, 2004 #8
    We do live in such a universe. It's called Tourette's Syndrome. :rofl:

    Seriously, I think this borrows upon the premise (which I personally don't subscribe to) that time can be broken into fractual components wherein each universe, based upon our three quantifiable dimensions, is a universe unto itself. When that fractual-second has passed, that universe has expired while another one dawns. The interconnectivity is through temporal mechanics that would of necessity dismiss such a cause-and-effect shift as tea or coffee.

    Just random thoughts, nothing substantial, still there you are...
    Last edited: Jul 12, 2004
  10. Jul 12, 2004 #9


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    I just jumped. It didnt do anything unexplainable.
  11. Jul 12, 2004 #10
    The world can be viewed as 'one or the other', but it is really 'one after the other'.
  12. Jul 17, 2004 #11
    Multiple universes

    It is possible to have multiple universes. You have two choices with the Big Bang. The first is that the Big Bang was a single event and the second is that it is one of many cycles. If it is one of many cycles then the next universe is just behind us maybe by just a fraction of a second. Since we cannot travel in time we do not know of its existence.
  13. Jul 28, 2004 #12


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    In a near infinant number of universes you are wondering why you made a not logical choice, and besides, its not just choices you make, the body is just a series of chemical and physical reactions, what makes that diffrent from the rest of the universe? Each alternate universe has something diffrent, not necissaraly a big thing just, like an atom or an electron or a photon out of place or not existing...
  14. Aug 14, 2004 #13
    Hi there!

    Can someone tell me who came up with this so beloved "parallel universes idea" in the first place?
    Is there an actual physical foundation for that nice idea that makes it useful in any way (except sci-fi of course :biggrin: )??

    Because to my eyes there is no reason why there should really exist any parallel universes, only because there are random events happening on quantum levels we are not able to predict.

    Of course you might say that there are infinitely many potential universes, but I believe any time such a "quantum choice" happens, only one universe "becomes real" - ours.
    There might still be other universes, but I think if there are, then they should be more than just "quantum variations".

    That's just my opinion, of course, but I really don't see any benefit in this concept - despite the "hope factor": if anything that is possible actually happens in some other universe, then there should be at least one universe with me being really happy and having gained all I ever dreamed of...
    Aaaawh - isn't that a nice thought? :uhh:
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