Hi Pragmatist
I've also seen this claim made many times. But the fact that the claim is made doesn't imply that it is true. The great majority of people who make this claim have no real understanding at all of QM, they read popular articles and believe that makes them experts and unfortunately many of those then go on to write their own articles. Like a game of Chinese Whispers the story gets ever more exaggerated and further from the truth along the way!
The links I provided were to proper papers. Are you telling me that if I read a paper in the American Journal of Physics, that I might be reading something written about Quantum Mechanics by a person not qualified to write about Quantum Mechanics? I mean.....I don't want to be rude by why should I trust you more than a paper in a scientific journal? You are just like me - posting on the JREF bulletin board. That paper is peer reviewed.
And there are a great many properly qualified scientists in the actual field who also don't really understand it! I don't pretend that I understand all of it either, but there are many obvious fallacies that I do spot.
Well, I'm not going to abandon my current understanding unless somebody can indeed point out what is wrong with the paper I posted. Sometimes I have to tentatively trust
somebody - and since nobody can be an expert in every field of science and every school of philosophy, so must everybody else.
There is a persistent confusion between time reversal symmetry and reverse causation. Essentially time dependent wavefunctions (some are space like and not time dependent) are symmetrical (mathematically) with respect to time. That means if time COULD run backwards the wavefunction would still make sense. (Although I must point out that there are some scientists who do NOT believe that, and there are "proofs" to that effect - I don't know how valid they are in the overall scheme of things) It is also generally accepted that in QM most things that CAN happen, DO happen. FOr example if you look at Feynman's sum over histories technique, he assumes that ALL possibilities are valid including time reversal. However, the whole point of sum over histories is that the relative phases of most paths cancel each other out and the result is generally a single result in a single direction. So taking that literally you can say that there is actually some reverse time element in every process, but that the overwhelming tendency of the process as a whole is to cancel out time reversal and force the result in a forward time direction. So the reverse time elements tend to be irrelevant in actual processes.
BUT, the fact of the matter is, this is only a convenient mathematical tool. There is no way to prove that ALL such processes actually DO occur. As is often the case, people confuse the possibilities inherent in a mathematical tool with actual reality. It's basically a semantic confusion.
I will have to do some further reading before I respond to the above, because right now I can't say I fully understand the relationship between time reversal symmettry and reverse causation.
It's pointless to argue that macroscopic reverse causation occurs solely on the basis of mathematical QM theories.
Well, I only got into the argument in the first place because I claim to have witnessed macroscopic reverse causation. Furthermore I believe that what I witnessed is mistaken by some people for "supernatural" phenomena. I would like to think that what I saw was the result of a natural process, and reverse causation would allow this to be possible. So from my perspective, I have more than just the maths to go on - and I am looking for a rational explanation for something I find very hard to rationalise any other way.
At the macroscopic level we observe realities like conservation of momentum and entropy which effectively force time to run in one direction.
It doesn't matter overall how many people are wrong about this or whether or not they agree with each other. The simple fact of the matter is that it is NOT an established fact and as such it cannot reasonably be used as evidence in support of a claim.
It is established as being within the bounds of believability. If it were true, it would not shatter science. If phenomena were found which involved reverse causation, we would not have to re-write physics. For my purposes here, I think that is all I could have hoped for.
I agree. But what does that mean? It's irrelevant whether some physicists argue about these matters. What matters is whether what you are claiming is supported by actual evidence.
Some things are fundamentally impossible to empirically verify. This does not mean they are not worth discussing, or not understandable. And I must re-iterate that I am not looking for evidence that reverse causation actually happens, just that reverse causation lies within the realms of the scientifically possible. And I maintain that it is, and I think you are basically accepting that, even though you do not personally feel you have any reason to believe it really happens.
For my personal part, I believe all the philosophising is unneccessary and only confuses the issue. I have no problem with philosophers and/or philosophy, but I believe a scientist should realise the distinction between science and philosophy and should attempt to rigorously maintain that distinction.
Amen, brother.
I am about to start a combined degree in cognitive science and philosophy, and it is the border between the two I am most interested in - especially from the POV of the cognitive scientists. I believe that cognitive science, as a field, may be guilty of not properly recognising the distinction between itself and metaphysics. Many cognitive scientists seem to assume a metaphysical position in order to carry out science, and then draw conclusions which are based upon the metaphysical assumption, but mistakenly believe that those conclusions are based on scientific evidence. They then seem to have some difficulty in believing that people like Shroedinger and Eddington really believed what they claimed to believe. If I have an agenda at all, it is to make sure that scientists in all fields, but especially physics and cognitive science, recognise where science stops and philosophy starts. But in your case I appear to be preaching to the converted.
I didn't say that, and again, this is irrelevant. I responded to your claim to Soapy Sam that Schrodinger's cat did NOT imply a breach of physical law. I pointed out that it DID breach physical law and that is precisely why Schrodinger proposed it, I also gave some background to help clarify WHY that was the case. You also further made the claim that Sam was wrong and that you were right. I then showed that was not true. Now you are arguing in effect that the whole area is too complex for ANYONE to say unambiguously that they are right and that anyone else is wrong - which is probably true, but it contradicts the specific claim you made earlier.
OK....I think.
The point is, do you accept that there was no justification for you to have claimed that you were right and that Sam was wrong? And if not, why not?
Well, there seems to be some confusion about what I was claiming to be right about. I was claiming that reverse causality was scientifically possible. And I still think I am correct. In actual fact, I have already said that I don't think Schroedingers cat is a very good thought experiment anyway, since the cat is an observer. Maybe schroedingers cat
does break physical law. I'm not sure that this fundamentally changes the rest of my position. Reverse causality doesn't just exist in the cat experiment.
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Originally posted by JustGeoff
OK.....the act of observation and the observer are not the same thing. I could be wrong, but I am guessing that in your understanding of reality there is no observer, only observations. This might be the point where philosophical differences cause our arguments to clash, because for me there is and observer. So I have to ask you to define what you mean by "observer" and "observation". It is the status and idenity of the mysterious "observer" which is one of the main roots of the problem we have on our hands. Is the observer part of reality? Or is reality that which the observer observes?
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No, I don't believe that there is no observer. Why would I believe that?
Plenty of scientific skeptics here have claimed it. There are just observations, they say, and no observers. If you try to defend hard metaphysical materialism then you can end up having to claim there is no
metaphysical observer.
Of course there MAY be an observer. I already explained exactly what the difference was between an observer and an observation. An observation is an interaction between a system and something which is used to measure. The observer is the guy (or gal!) who reads the output of the measuring device......
But aren't they just part of the system too?
What is a guy making an observation apart from a bunch of atoms containing a brain with some signals flying around it? This is why you
cannot make sense of this question without reference to metaphysics. Basically, if you are a physicalist you cannot define
observer as anything apart from part of the system which is being observed. If a human being is only a brain, what distinguishes that brain from the quantum system he is "observing"? This problem is exclusive to physicalism. If you are a dualist, or an idealist like Eddington and Schroedinger, or a neutral monist like Bohm, then you can use ontology to define what you mean by observer. The physicalist cannot do so. But you have told me that you wish to play the role of
scientist rather than philosopher. I have to ask you now whether you believe you have made any metaphysical assumptions in order to define "observer" as "the guy making the measurements".
You have said that you don't think the definition/identity of the observer makes any difference. I think it is
absolutely critical, and so did Schroedinger, which is why he wrote about it.
I don't think the identity of the observer makes much difference - do you need an ID card to be able to read an instrument?
No, but you might need a metaphysical assumption in order to claim that a brain can collapse a wavefunction.
Yes, I would agree with Schrodinger. But I don't see the relevance of introducing the ego into the matter. There is a big distinction between someone's "world picture" and what is objectively measurable.
"Ego" is a bad word, because it has been used by other people in a very different sense. Schroedinger used it, but he also used "percipient" as in "that which percieves" - and that is a better word. He is talking about the fact that the thing which is doing the observing doesn't appear in the picture that is being observed. You see - if you agree with schroedinger on this then you cannot also claim that "the guy doing the measuring" is the observer because "the guy doing the measuring"
does exist within our scientific picture of the world. We know what brains are. We can see ourselves. What we cannot see is the thing which is actually observing the picture.
So I'd like you to clarify to me how you resolve this apparent contradiction.
Because I can design conditions under which the influence of the observer is minimal or where it cancels out. When I do so, I get consistent, replicable results which are confirmed by other experiments in which other methods are used to eliminate the observer influence. I then note that when the experiment is observed by a large number of different observers with different personal world views they all agree on the result.
This is abscence of evidence, rather than evidence of abscence. Under certain conditions, we have seen that sometimes experiments can be influenced by people having different worldviews, and the precise reasons for this have
not been established. I think this is a dead-end line of debate though. We have already gone down that path several times.
I already answered this before. I believe quantum outcomes are physically determined.
OK. So you are a hard determinist, yes?
Do you believe that the whole future of the world is therefore pre-defined?
I know you believe that. But it is a semantic non-sequitur. "Reality" is what is. What you personally believe or make up may seem "real" to you, but it doesn't necessarily constitute "reality" in a wider sense.
What
does constitute "reality" in a wider sense?
As a scientist, I don't see how you can avoid metaphysics in a discussion about "what constitutes reality?" That question is the very definition of ontology.
I can see that you want to make some philosophical issue of all this, but *I* don't. I am only commenting on what you CLAIM is scientifically supported or not. I'm not interested in discussing philosophy because I believe it's a pointless exercise with no end. Particularly where solipsism is involved.
I don't like solipsism either, Pragmatist. However, Schroedinger and Eddington
weren't solipsists.
My view is pragmatic (surprise, surprise! ). All the fancy philosophising and speculation doesn't count for a hill of beans in the real EXPERIENTIAL day to day world.
Too right. Experiences, yes.
For example, you can construct some personal reality in which gravity doesn't exist. You may convince yourself that is true.
That would be rather hard. I don't see how you can construct a personal reality where there is no gravity.
Fine. But I will bet that if you step off a cliff you will fall down and go splat just like anyone else!
I would do if "contructing a personal reality" consisted of no more than constructing a false picture of consensus reality and then believing it was real, yes. However, that isn't "constructing a personal reality". It is "falsely believing you have constructed a personal reality".
So it's irrelevant to me personally whether some philosopher disagrees with me about the "reality" of this world, unless they can show me hard evidence to the contrary, I will continue to believe that it IS real and continue to defy them to step off the nearest cliff to prove me wrong!
But always accepting the possibility that their failure to prove you wrong doesn't amount to any sort of proof by you that they are actually wrong.
Personally, I like living in a world of diverse beliefs. I have no need to prove anyone else wrong - not even Sam - I was trying to prove that I wasn't wrong, and used sloppy language to do it. I am just defending myself from an accusation that I am neccesarily wrong. I'm not trying to prove I am right, any more than you are.
The original point you made was that Bohm introduced explanations that were not thought of at the time when the original Copenhagen interpretation was an issue. I don't believe that is true because Bohm's work was essentially just a refinement of work that De Broglie introduced 30 or 40 years before that - at the time of the Copenhagen dispute. Therefore, unless you have some specific scientific evidence to the contrary, I believe that your argument is inaccurate. The SCIENTIFIC propositions of Bohm were to all practical intents and purposes considered at the time of Copenhagen because De Broglie introduced them then.
Accepted.
