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Your memories are almost certainly false

  1. Apr 25, 2010 #1
    It’s overwhelmingly probable that all of your memories are fake.

    Consider:

    Entropy is a measure of the disorder of a system. The higher the entropy, the higher the disorder.

    If a deck of cards is ordered by suit and then within each suit by ascending rank, then that’s a low entropy state. This is because out of the 8.06 * 10 to the 67th (52!) possible unique arrangements of the cards in a standard 52 card deck, there’s only 24 that fit that particular description.

    A “random looking” arrangement of the deck is a high entropy state, because there are trillions of unique arrangements of a standard 52 card deck that will fit the description of looking “randomly shuffled”.

    Same with the egg. There are (relatively) few ways to arrange the molecules of an egg that will result in it looking unbroken, compared to the huge number of ways that will result in it looking broken. SO, unbroken egg…low entropy. Broken egg…high entropy.

    AND the same with the universe…there are (again, relatively) few ways to arrange the atoms of the universe in a way that makes it resemble what we see with people and trees and planets and stars and galaxies, compared with the gargantuan number of ways to arrange things so that it resembles a generic looking cloud of dust.

    OKAY. Now.

    Of the relatively few ways that the elementary particles of the universe can be arranged so as to resemble what we see around us today, only a tiny fraction of those particle arrangements will have values for momentum and position that are consistent with them having arrived at that state 13.7 billion years after something like the Big Bang.

    The vast majority of the particle arrangements that macroscopically resemble the world around us will *instead* have particles in states (e.g., with positions and velocities) that are consistent with the particles having previously been in something more like a giant dust cloud.

    By which I mean: If we take their current positions and velocities, and work backwards to see where they came from, and go back far enough in time, eventually we will not arrive at the Big Bang. Instead we will arrive at a state resembling a giant dust cloud (probably a very thin, spread-out dust cloud).

    SO, bottom line:

    Out of all the possible configurations that the universe could be in, ones that have people, and planets, and stars, and galaxies are extremely rare.

    Further, even if we then only consider those extremely rare possible configurations that have people, and planets, and stars, and galaxies – the ones with particles in states (e.g., with positions and velocities) that are consistent with having arrived at this configuration 13.7 billion years after something like the Big Bang are STILL rare.

    We don’t know the exact state of our universe’s particles, but in statistical mechanics the Principle of Indifference requires us to consider all possible microscopic states that are consistent with our current macroscopic state equally likely.

    So given all of the above, and our current knowledge of the laws of physics, the most likely explanation is that all of your current memories are false and that yesterday the universe was in a HIGHER state of entropy, not a lower state (as would be required by any variation of the Big Bang theory).

    Physical systems with low states of entropy are very rare, by definition. So it’s very improbable (but not impossible) that the unlikely low entropy state of the universe of today is the result of having evolved from an EVEN MORE UNLIKELY lower entropy universe that existed yesterday.

    Instead, statistically it’s overwhelmingly more probable that the unlikely low entropy state of the universe today is the result of a random fluctuation from a HIGHER entropy universe that existed yesterday.

    And thus your memories of a lower entropy yesterday are most likely due to this random fluctuation, not due to yesterday actually having had a lower entropy than today.
     
  2. jcsd
  3. Apr 25, 2010 #2
    ok, that's quite an idea... but doesn't every spontaneous action increase the entropy of the universe... For the universe to become less random, more ordered, it would have to be increasing in energy... Since thermodynamics tells us that energy cannot be created or destroyed, I'm going to have to say that the universe is becoming more and more disordered, presumably from a very ordered point, to eventually a thin dust cloud..
     
  4. Apr 25, 2010 #3
    Two wikipedia articles of interest:

    http://en.wikipedia.org/wiki/Boltzmann_brain

    http://en.wikipedia.org/wiki/Poincaré_recurrence_theorem

    Also check out the references on the first article...
     
  5. Apr 25, 2010 #4

    apeiron

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    Except brains and bodies are dissipative structures that pay for their order by their more rapid degradation of entropy gradients.

    The second law of thermodynamics has more complex consequences than those you are using in your argument here.
     
  6. Apr 25, 2010 #5


    Did he say human bodies violated the 2LOT? What does the fact that human bodies obey the second LOT have to do with how likely it is for something similar to a universe and a conscious human being with memories to emerge out of a quantum 'soup'?


    Again, this does not prove his idea is wrong. As far as i can see, RexAllen is trying to evaluate how likely it is for anything to emerge in a state that we might call a Big Bang and enfold to its current state. And as far as i can see his point, even the 2LOT is a statistical occurence that happens to make sense to us because if it had not, we wouldn't be here and definitely not made it that far development-wise.
     
  7. Apr 25, 2010 #6
    Anthropic principal, only in a universe where an intelligent entity exist is it possible for there to be questions and ideas such as these.

    Thermodynamics, I can take energy from a to make b more ordered, though in the end, the total disorder in a AND b after the transaction will be greater than before the transaction. To put it in words of someone who almost discovered the sun...
     
  8. Apr 25, 2010 #7
    Nothing in the original post contradicts the second law of thermodynamics. Read the wikipedia links and associated references.

    This idea isn't original to me. In fact, it's not even especially obscure...note the article in the New York Times listed in the references to the first wikipedia link.
     
  9. Apr 25, 2010 #8
    It's a well known problem and I mentioned it in the last thread you posted. The answer is that if all our memories are false then so is the second law of thermodynamics - it undermines itself. That's why we need to assume the universe started with incredibly low entropy.
     
  10. Apr 25, 2010 #9

    disregardthat

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    In the case of memories, they are "false" for entirely different reasons than this. We are remarkable incapable of maintaining an accurate picture/description of a situation over time. Our memories are also changing over time, even new elements can be included.

    Taken in the general perspective, that something cannot be a "true" description/representation of something else over time, I will question this by asking what is a "true" description anyway?
     
  11. Apr 25, 2010 #10
    Well thats a different discussion entirely, more of a psychology argument... If people remember something different than what actually happened, did it actually happen? Who is to say that events are not defined by perception?
     
  12. Apr 25, 2010 #11
    Well my memorys are not false... And I personally wouldn't label the universe in terms of order/disorder because one mans order is the other ones disorder. As I understand it for the universe to be going into a more entropic state things would have to be getting more complex and well... they are imo.
     
  13. Apr 25, 2010 #12

    disregardthat

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    I'd say it's more of a question of how our language and other forms of expressions relates to the world.
     
  14. Apr 25, 2010 #13
    If I might can I ask these questions of you all?
    How do you define order?
    How do you define chaos?
     
  15. Apr 25, 2010 #14

    apeiron

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    Thanks, I'm familiar with the Boltzmann Brain argument. And the fact that it seems possible to extract ludicrous consequences from a premise is normally evidence there is something wrong with the premise.

    In this case, it is that the second law is being used too simplistically. Entropy degrading systems in fact have high probability of occuring where there is an entropy gradient.

    So if you truly want to calculate anthropic probabilities, you have to go back to the question of how such cosmological-scale gradients might arise.

    Even your "dust cloud" universe would be still expanding, still cooling. It would still be a gradient (even if a much weaker, duller heat death one).

    When thinking about the cosmological scale, you need to include both the global scale (the void, the vacuum, the de sitter event horizon) and the local (the dust, the atoms, the background radiation) in the calculations.

    The void is often treated as if it is "just nothing" and so can be left out of entropy maths. Yet clearly it is a very orderly and continually developing "something".

    Unless you take a completely solipsistic line with Boltzmann brain, saying that even all cosmological facts are the imaginings of a mind that fluctuates into momentary being. But then how would any entropic arguments be of interest if everything has been faked in this (now inexplicable) way?
     
  16. Apr 25, 2010 #15
    Sean Carroll's From Eternity to Here has a good discussion of these issues.

    Particularly this chapter:

    http://blogs.discovermagazine.com/cosmicvariance/2010/03/16/from-eternity-to-book-club-chapter-ten/

     
  17. Apr 25, 2010 #16
    I can be rather dense. How did you get from this,
    to this?
     
  18. Apr 25, 2010 #17

    It might make more sense if you put this between the two paragraphs that you quoted:
     
  19. Apr 25, 2010 #18

    Char. Limit

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    Well, I'm no philosopher, but order to me is having fewer possible microstates, and chaos is having more possible microstates.

    [tex]S=k \times ln{W}[/tex] FTW!
     
  20. Apr 25, 2010 #19
    OK. Got it. Not so very different from stray thoughts of my own, but in very different words. Say we are willing to put aside, for the moment, the concept of linear time and replace it with the concept of multiple pasts and multiple futures, what would we cognitively record in memory? It should be safe to say that the process of cognition, and therefore memory storage itself is a process that involves an increase in entropy from information loss.
     
  21. Apr 26, 2010 #20
    Aside from epistemological issues there is a known phenomenon of degradation of information storage in the brain. Our minds do not like gaps though so when we do not clearly remember something we often unconsciously mend the gaps in the degraded memory by patching it with what ever information seems most likely or appropriate there by altering the stored memory.

    edit: this is actually more along the lines of what I thought the thread was going to be about when I first clicked it.
     
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