the underlying assumptions rig the debate

I agree. I object to this approach for the same reasons you described.At heart this is just a variation of Last Thursdayism, the difference being that in this perspective the universe was modified last Thursday instead of being created last Thursday.I don't know why anyone thinks this could be a reasonable argument. It allows anyone to argue, "Well, that may be what the evidence says, but that's not what actually happened because the evidence was changed, and no trace was left behind of the change."Since science is based upon evidence, and since this approach by its very nature claims that the process of change leaves behind no evidence, this cannot be a scientific position. It is, as you say, a fun mind game suited for sci-fi movies.--Percy

I may not be following PaulK correctly, but what he should be saying is that it isn't the past that changes, only the present. The collapse of the wave functions to a single possibility for each particle happens in the present, not the past. In the past the particles continue to exist in their superimposed state.You see, the observation doesn't change the past so that from the outset of the original entanglement one particle had one spin and the other the opposite spin. Quantum theory experiments have established beyond any doubt whatsover that up until the observation both particles existed in a superimposed state.In other words, the observation isn't revealing to us what state the particles were actually in. And it isn't retroactively changing the state in the past to what was eventually observed. Prior to the observation the particles existed in a superimposed state. This much we know for certain.There's another perspective on this discussion. If your view were actually a valid conclusion of quantum theory then it would be famous and you would be able to walk into any bookstore and find book after book about it. It would be the basis of thousands of time-travel sci-fi stories.But this supposed aspect of quantum theory isn't famous, and not even sci-fi writers have latched onto it (well, that would be expecting too much, probably some have). That's because you misunderstand the implications of entanglement.--Percy

This is a pretty clear misunderstanding of quantum theory. I won't go into detail as I see the discussion has moved on by 30 messages since I last posted.--Percy

Iblis never expressed any doubt about the possibility of quantum computers. What he explained to you is that it is a misinterpretation of entanglement to believe you can transmit information faster than the speed of light. You can't.Iblis also never rejected "80 plus years of development of quantum theory and hard experiments." He's pointing out your misinterpretation. It is your own viewpoint which is the one that is contrary to contemporary understanding of quantum theory. Iblis was only saying that the Wiki article makes it easier to reach misunderstandings like yours. He's not saying the results of the experiments aren't real, which is what you mischaracterize him as saying, but that the conclusions you reach from reading descriptions of the experiments are incorrect and don't actually follow from the experimental results.Let me return to a point I made earlier. Were your interpretation actually the correct one and it is just a group of us here at EvC Forum that have fallen into a misinterpretation but that the rest of the scientific world shares your interpretation, then you could walk into the science section of any large bookstore and find popularizations of quantum theory that include descriptions of how one day we might be able to retroactively change past events. But such books don't exist. That's because the scientists whose views such books attempt to represent don't think this is a valid interpretatin of quantum theory.I do think that Iblis makes an error in his appendix example at the end of his message. It implies that the difference between the two particles actually existed back in time, we just didn't know which was which until later. I don't believe that's correct.I like Wikipedia a lot, but I've found that one has to take care and not be too trusting. Much of it is fine, but for subtle or complex topics it is a good idea to find confirming sources. Anyway, about quantum entanglements Wikipedia includes this comment: It doesn't get any clearer than that.--Percy

Duplicate content removed, website is somehow misbehaving today, very strange!Edited by Percy, : Duplicate post.

Of course there is. My favorite is David Gerald's The Man Who Folded Himself.But you've misunderstood the point, which was that if your view were the one actually shared by physicists, then science fiction writers would have picked up on it as a mechanism for time travel stories. I was trying to get you to see that isn't just at EvC Forum that no one agrees with you - no one agrees with you anywhere, not even science fiction writers.The other part of the point was that if your view were correct, then you could walk into bookstores and find science popularizations talking about what scientists have discovered about the possibilities of changing the past. But you can't find such books. Because they don't exist. Because scientists don't believe the present can change the past. Then why are you here? Seriously, I wasn't introducing fiction into the discussion. I was making the point that even those who stretch the views of science for a living haven't gone where you are going. It was just an attempt to get you to see just how far "out there" you are. Really? I didn't know that. I don't think anybody knows that there's causality backwards in time. You keep saying stuff like this, and everyone keeps telling you that we all accept and understand entanglement, and we all accept and understand the 2-slit experiment. What we're telling you is that you are drawing incorrect conclusions from these experiments. These experiments are not demonstrations of backwards causality. Backwards causality is just your misinterpretation. Omigod! Don't tell me you also believe entanglement makes possible faster than light communication! That would be almost too funny! Look out, Alice and Bob, here we come!--Percy

We're talking about the same experiments. It has already been pointed out multiple times by multiple people how you are misinterpreting the English descriptions to reach false conclusions. My descriptions are just my own poor attempts to present the current scientific interpretations of the same experiments.The thing I don't understand is why you believe backward causality is an accepted view within science. It isn't. I also don't understand why you believe there is strong experimental support for backward causality. There isn't.One other thing. The backward causality you're arguing for doesn't even provide what you need to support your claim that the past that actually happened is different from the evidence about that past that we find today. Your backward causality changes the past to correspond to what we find today. So you're not only wrong about backward causality, it doesn't help your original point anyway.--Percy

Hi Randman,Well, as anyone can see, your message is dated 5/7/2003, more than three years ago. I don't know how you did it, but I think we have to accept this as a demonstration that the present can indeed change the past. Someone please notify the physicists.--Percy

Hi Randman,This isn't to you, but to everyone else.To everyone else,Just because creationists often quote kooks and loons as if they were true scientists does not justify not doing due diligence. Concerning this paper from Oak Ridge National Laboratories (http://www.ornl.gov/~webworks/cpr/pres/107480_.pdf), it would seem that there are scientists out there who are exploring the possibility of superluminal communication. Personally, I'm stunned. My understanding of how most scientists understand relativity and quantum theory is that this simply isn't theoretically possible, by which I mean the math disallows it.I'd like to get a clear understanding about this. Just how far out on the fringe are these scientists? They seem to be following the principle that anything not explicitly disallowed is permitted, and they believe they have a theoretical perspective consistent with modern quantum theory that permits superluminal communication. At a minimum it would appear that acceptance of a speed limit is not as widespread as we've been maintaining.--Percy

Cavediver,I still have questions, though. ORNL is a top-notch and highly respected research facility, isn't it? Why are they engaged in things so far out on the fringe? It lends greater legitimacy to the speculations than they would seem to merit.I don't have a perfect memory by any means, but I think I would have remembered any full article in New Scientist or SciAm seriously reporting possibilities of superluminal communications. Until Randman's ORNL reference, I hadn't seen the idea receive any serious consideration before. In fact, SciAm had an excellent article around 5 years ago explaining quite clearly why entanglement can't be used for the communication of information.Randman,There are a huge number of scientists out there. We can confidently state that science accepts Einstein's general theory of relativity, and the fact that some legitimate scientists reject some or all of general relativity does not alter the scientific concensus about relativity.A scientific consensus that is broadly accepted also exists around quantum theory. Yes, there are scientists outside this consensus, but pointing to them and their work as evidence that we have the consensus wrong or that the consensus doesn't exist is just barking at the moon. You can walk into any bookstore or library and find book after book about quantum theory repeating the same things we're telling you here, because such books generally present the scientific mainstream. But while some of these books will contain sections on speculative ideas upon which there is no consensus, and some of the books may be entirely about such speculative ideas, it would be a serious mistake to conclude that the ideas are accepted within the mainstream. For that to happen they need a stronger theoretical and experimental foundation. To this point in time, the theoretical objections to suspension of causality are apparently extremely strong, and no experimental evidence for suspension of causality exists, either.And there's nothing wrong with scientists working outside of or against the mainstream. It is important that the scientific mainstream be constantly challenged. But you're making the mistake of pointing to the speculative and fringe ideas and claiming they represent mainstream views. For example, you keep quoting Wheeler. Whether or not the quoted excerpts accurately reflect Wheeler's views, they are not in any way representative of the scientific mainstream.I think it would serve your cause better if you made claims that when assessed by other people would be found to have merit. For example, you could quite correctly state that there is a small community of scientists who believe superluminal communication is possible, and taht they are conducting serious research into the idea. But people are unlikely to find any merit in the argument that because this community exists that therefore their ideas should be accepted as correct.--Percy

An excellent plan! You should be sure to look at a complete and representative selection of experiments, papers and public writings instead of cherry-picking what agrees with your preconceptions. As has been pointed out, phrases like "seems to know" and others are just the best that can be made of an impossible task, namely rendering the math into accurate English descriptions. These phrases are leading you to reach unintended (and incorrect) conclusions. I'd say the jury is still out about whether Wheeler accepted violations of causality. Even if he did, it is not a currently accepted view within science because it has no theoretical or experimental support. And when Feynman said that no one understands quantum theory he was speaking generally and colloquially for a lay audience. He definitely was not saying, "Is causality violated? Heck if I know!" It appears to everyone that you are misinterpreting the experimental results. Look at it this way. If the experiments indicated what you think they do, then why are the scientists pursuing these ideas still seeking both theoretical and experimental validation, for example, in the paper you linked to from ORNL. If it is as you say and the experimental results make causality violation and FTL communication a done deal, then why do the efforts focused on these areas appear to be approaching them as still unproven and undemonstrated?There's a difference between an intriguing idea with possibilities and an idea that already has both theoretical and experimental support, but you seem to continually confound the two. We all want science to move forward, but before we plant our flag in new territory we want to make certain it is solid ground and not quicksand.--Percy

I wouldn't argue in this way again if I were you. Let me say again that it would help your case immensely if you could paraphrase the positions of those you're discussing with more accuracy than this. No one here has ever denied the experiments were done in the real world. No one here has ever claimed that they were only thought experiments. But theory and experiment have marched forward roughly together in quantum theory. Experiment is validation of the theory, and theory points the way toward experiment. It is the mathematical theory that provides the interpretational framework for the experiment, and you're misinterpreting the descriptions.As I already said, if your interpretations were correct and what you were claiming had already been established, then explain why groups like those at ORNL are still approaching the problems as if they are not yet established either experimentally or theoretically. Even just the phrase "appears to know" when applied to a photon is so obviously euphemistic that to point it out hardly seems necessary.--Percy

Concerning causaility, first you provided a Wheeler quote of questionable origin from Paul Davies, then you provided a quote about observers that had nothing to do with causality. Did I miss anything? If that's the sum of your evidence that Wheeler accepted violations of causality, then yes, the jury is still out. Way out. It's even premature to have a jury.But the Wheeler quote is unimportant. Whether he accepted causality violations or not, this view has not found anything approaching wide acceptance within physics. You offered the quote as support for causality violations. As I already said, the quote was offered generally about quantum theory, not specifically about causality violations. That famous Feynman quote is in no way a statement about his views on causality violations. Do you misinterpret points on purpose or does it just come naturally?Of course we're still running experiments verifying GR and other accepted theories. But efforts at further verifications of GR can and do point to past validations. That paper from ORNL made clear that there are no prior theoretical or experimental validations.This whole discussion just boils down to you trying to convince people that some stuff that is pretty far out there on the scientific fringe is actually accepted mainstream science, or that the possibilities hold much more promise than is actually the case. And you're trying to do this because central to some of your objections to modern scientific views is that the past was actually different from the evidence we have of that past. But even your interpretation of quantum theory doesn't allow this possibility. In the view your arguing for, the present would change to be consistent with the past, including the evidence we have of that past. Any such changes of the past would be indetectable today because the evidence would have changed, too.--Percy

Then you need an actual quote in order to show this. This is all you provided from Message 150: That's not a quote. I'd be the last to claim a perfect memory, but I've seen one of the lectures where he says this (I'm sure he said it many times), and he said it very early in the lecture before he'd gotten to any details.I'm not trying to give you a hard time. I just think your claims should have better correspondence with the actual situation within science. Maybe one day we'll uncover convincing evidence of causality violations, but it hasn't happened yet, and to claim that it has is just plain wrong.--Percy

I guess I should add that even if he said it in the context of the 2-slit experiment, it still can't be construed that Feynman accepted causality violations as experimentally established.If causality violation had been demonstrated experimentally, then you would be able to find sites all over the net saying things like, "The experiment that first established causality violation was...etc...".It should tell you something that the best you can do is find quotes about something else and claim that they're about causality violation.--Percy