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Proof that ghosts don't exist

  1. Apr 15, 2009 #1
    How could one go about proving that ghosts do not exist?

    Seems like we could make some basic assumptions about what ghosts are, and proceed to prove that that particular 'brand' of ghost cannot exist.

    Any ideas?
  2. jcsd
  3. Apr 15, 2009 #2

    Ivan Seeking

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    We can't prove a general negative. We can only offer evidence of an explaination for specific claims, or for specific types of claims.
  4. Apr 15, 2009 #3
    Furthermore, it's not really your job to prove that they don't exist. It's up to the person making the claim to provide evidence and construct a "proof" of the existence of ghosts.
  5. Apr 15, 2009 #4

    Ivan Seeking

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    Not really. In principle the person making the claim is merely providing a report. If I report a robbery, am I liable to explain who did it, or how? My wife and I had some unsual experiences, but that doesn't mean that I know what it was or how to explain it. There is a difference between reporting an observation and claiming to have an explanation for it. Likewise, a claim of an observation or experience only counts as anecdotal evidence for whatever is claimed.
  6. Apr 15, 2009 #5
    But making a claim to 'have seen a ghost' isn't providing a report, it's trying to provide an explanation. If someone claims to have seen a ghost, they should give evidence to why it was "a ghost" and not just something that seemed mysterious.
  7. Apr 15, 2009 #6

    Ivan Seeking

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    The word "ghost" carries with it certain ideas about what we mean, but you are right in that the person making the claim should report exactly what was observed without adding any interpretations of what it might be. In fact that is part of what we like to do here: Make the distinction between evidence [be it anecdotal, scientific, or otherwise], and interpretations of that evidence.
  8. Apr 15, 2009 #7
    Yes. I was thinking about something like the commonly thought 'characteristics' of ghosts and if it could be shown that such a thing cannot exist. Characteristics such as:
    a. they can go through walls,
    b. they possess intelligence,
    c. they can move things,
    d. they appear as 'foggy-looking' see-through-type beings,
    e. etc. (Not sure if I'm forgetting something....)

    Could it be shown that a 'being' with these characteristics cannot exist?
  9. Apr 15, 2009 #8

    Maybe 'proof' is a bit strong. I guess what I'm asking is if we can make a strong argument against the existence of ghosts, and how we might construct such an argument.

    Sorry to double post.
  10. Apr 15, 2009 #9

    Ivan Seeking

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    I think it fair to say that there is no accepted scientific evidence that ghosts, as suggested, exist. Given that, we have no explanation for what "ghosts" may be if they do exist. So already we can say that there is no known explanation for what people report. We could assume some model for ghosts and show that such a model would violate the laws of physics, but we would be working on assumptions, so the respective conclusions wouldn't mean anything except within the context of the assumptions made for the "ghost" model.

    We already agree that the popular view or "model" for ghosts seems to violate the laws of physics and the notion of consciousness as we understand it.
    Last edited: Apr 15, 2009
  11. Apr 16, 2009 #10

    Ivan Seeking

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    It is always possible that some claimed phenomenon, such as the claims of hauntings, will finally yield evidence that can be duplicated for proper study and peer review. In that event, it may be that physics will have to adapt to a "new" reality. But we have seen this before. Much of scientific knowledge was discovered, not predicted. For example, to this day we can't fully explain how lightning occurs. The issue of charge separation continues to haunt atmospheric scientists.
  12. Apr 16, 2009 #11
    Science can only explain so much and that probably is not very much at all.Personally I rather like the concept of all the ghosties and ghoulies and long leggedy beasties.The world would be a less fun place without Casper.
  13. Apr 17, 2009 #12
    Those who sell the idea of ghost haunts use terms like 'paranormal' and 'supernatural' that, by definition, exclude science from pouring cold water on their burning enthusiam.
  14. Apr 17, 2009 #13

    Ivan Seeking

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    Those are the words used because we don't have any others to offer.

    How does a word carry any significance at all here? What matters are the claimed phenomena.
  15. Apr 17, 2009 #14
    The problem here is that no one has defined what it is they mean by "ghost", so there's not really any discussion to be had. If you say they're supernatural or paranormal then, by the definitions of those words, you can't "prove" anything about them one way or another. If you claim they aren't supernatural then we should be able to find physical evidence to support the proposition that ghosts exist. So, where's the evidence?
  16. Apr 17, 2009 #15


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    No, but if you report a robbery and a robbery didn't happen, you go to jail for it. That's roughly the situation here. If someone reports seeing "something", that's fine. If someone reports seeing "a ghost", then they are responsible for proving that claim. "A ghost" isn't scientific data, Ivan, it is a claim and one that requires substantiation. Evidence that (for example), a cloud on a phot isn't just a cloud of dust but an actual ghost.

    This is the problem with most of the typically accepted psuedoscientific pursuits: they skip half the steps of the scientific method and go about trying to gain evidence for something that hasn't been scientifically suggested, but is merelly assumed to exist. As a result, any evidence that isn't conclusively found to be something else is assumed to be that which they are looking for. It's using falsifiability to prove an hypothesis that isn't really falsifiable.
    Last edited: Apr 17, 2009
  17. Apr 17, 2009 #16
    a claim about non existence , could be done by statistical proof or analysis

    ghost , elves do Not exists because using statistic yo do not see them every day

    for example i know electrons exists because i can go to a lab and measure them if i want, but i can not see or measure a ghost
  18. Apr 17, 2009 #17

    Ivan Seeking

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    That is an assumption that can't be substantiated.


    An if they report seeing a floating head passing through the livingroom?

    REALLY? I was sure there is a section in my physics books somewhere. :rofl:

    No it is a word. Would you be happy is they said floating head, instead?

    Tell me precisely what a ghost is so that we know what proof to require.

    People make interpretations based on popular notions. I have already addressed that as a legitimate issue. Please read before posting.

    Who is they?

    You mean based on a claim.

    The problem with reports like hauntings is that they can't be produced on demand and repeated in a laboratory. As I have asked before: Precisely what evidence would be sufficient; Casper in a bottle? Unless you can provide a list of required evidence, you can hardly complain about not having it.

    Assuming that some people are indeed reporting genuine unexplained phenomena, the problem is the nature of the phenomenon, not the observers. We have the same problem with any phenomenon that can't be produced on demand, like ball lightning.
  19. Apr 17, 2009 #18

    Ivan Seeking

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    Russ, all that you are really objecting to here are stories that you can't explain. If you can explain them, then you don't object.

    Sounds like anti-science to me - it only exists if I understand it.
  20. Apr 17, 2009 #19
    About 1 percent of the population is schizophrenic. Some schizophrenics believe that the voices they hear or the things they see are real. Some will atribute what they see to ghosts.

    I think that John Nash:


    believed he had some family members or friends who in reality do not exist.
  21. Apr 17, 2009 #20
    No one is saying that there is no such thing as unexplained phenomena, in fact saying something as general and vague as that is almost entirely pointless. If everything was explained already, then this whole "science thing" would be irrelevant.

    Of course, saying that you saw a ghost (by the way Ivan, definitions ARE important contrary to what you seem to believe) is providing an interpretation of an event that requires evidence. I would very much prefer that an observer simply describe what they saw rather than attempt to provide their own interpretation. I realize getting someone to provide a description that doesn't presuppose some interpretation is probably impossible, but they should try.
  22. Apr 19, 2009 #21
    Walls only appear to be solid structures. They are mostly just empty space and lots of things can go through them, such as waves, or high energy particles.

    We could infer that a brain is required for intelligence because all intelligent organisms we know of have one, but we don't have the slightest clue what causes self awareness. Without knowing the source of that, you can't rule out the possibility that something like a "soul" exists which is separate from the body. For example, one might argue that the brain is only necessary to bind the soul to the physical world. I personally do not believe in ghosts, but I find the mere existence of self awareness in humans to be equally spooky.

    The bottom line is that self awareness cannot be explained by any model of physics that we know of, and until we know more about it, it's not possible to make assumptions or proofs relating to it.
  23. Apr 19, 2009 #22
    Do you really think it's even remotely possible that there's a "soul" that can exist apart from the body?
  24. Apr 19, 2009 #23
    Modern science has shown us that the brain is responsible for sustaining consciousness, that our memories are stored non-volatilely in the neural and glial connections, that our emotions are regulated by chemical reactions. The brain is a turing complete machine and evolution provided a mechanism for optimizing that machine to maximize reproductibility of the human race. Ok, so this can explain the arbitrarily powerful computing machine we lug around on our shoulders that's apparently capable of surprisingly general computations involving pattern recognition and planning problems.

    Going back to the OP for a moment, I guess I do need to revise my original statement a bit: I think that from this, we could conclude that in order for a consciousness to have memories or feelings, it must be linked to a functioning brain. Therefore, if it was possible for the consciousness / spirit / self-awareness-unit to be separated from the physical brain, it would not have the memories or emotions that are so commonly attributed to ghosts (and of course, it would not be visible as an ethereal visage).

    Going back to your question, zooby -- do I believe that it is actually possible for this "soul" (which I equate to the self-awareness component of the brain) to be separated from the brain? Well, it depends on what you mean by that. I certainly do not think that "we go on thinking after our body dies." I take as empirical proof of this the fact that a person can be knocked unconscious. I personally have gone unconscious on several occassions due to lack of oxygenated blood flow to my brain and during that period my self awareness was most definitely offline, so it only stands to reason that it would continue to stay offline.

    What modern science doesn't explain, not even remotely, is how this machine could possibly be aware of it's own existence...and how that awareness could be physically linked to the brain so that chemical levels could be registered as feelings. Also, I think we can all agree that self awareness is not required for reproduction...nor is it required for evolution...nor is it required for a general purpose computer that interprets sensory inputs and controls an organism throughout it's lifetime in the search of self preservation and reproduction. This begs the question: why are we self-aware at all?

    Judging from the beautiful efficiency, diversity, and capabilities of organisms on this planet it seems to me that evolution is quite a powerful force for constructing an organism that is as efficient as possible. This suggests to me that, while self-awareness is clearly not necessary, it must somehow simplify the structure of the brain to have it there.

    Now what could simplify the structure of the brain? Well, reusing an existing component. In other words, if there were some form of external "spiritual power", to which an input/output connection could be established via a physical brain, and the brain could then offload complex decisions to it. For example, this would be akin to building a quantum computer and then exploiting quantum mechanics to solve NP-hard problems that our conventional binary computer's cannot solve efficiently. Perhaps there's something like this...on another level...that our brains are outsourcing to for thought.

    I don't know. I'm just rambling here, musing...but given the fact that self-awareness can't be explained by the standard model, general relativity, quantum mechanics, string theory, or anything else...I don't see that we can really rule much out.
    Last edited: Apr 19, 2009
  25. Apr 19, 2009 #24
    No experiments involving (self aware) persons have ever demonstrated a violation of the known laws of physics. Therefore one cannot make the case that the known laws of physics are incompatible with self aware beings.
  26. Apr 19, 2009 #25
    Quantum mechanics is incompatible with the existence of ghosts. A ghost could e.g. observe which path an electron takes in a two slit experiment.
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