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Author Topic:   the underlying assumptions rig the debate
Percy
Member
Posts: 22505
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.4


Message 171 of 246 (323399)
06-19-2006 4:50 PM
Reply to: Message 168 by randman
06-19-2006 4:09 PM


Re: superluminal potentials still under debate
randman writes:
You are confusing issues here. You guys brought up superluminality...
Superluminality was merely mentioned in passing as part of an explanation from Iblis in Message 41 about how entanglement really works, and only to say superluminality isn't possible. It was one sentence in a long post. It was you who later went off and found a paper from ORNL which you then offered as proof that we had our heads in the sand regarding superluminality. Now you're acting as if you knew it hadn't achieved wide acceptance all along:
...that is indeed an area of research that is contested...
No kidding!
So how you decide to measure determines the past in these experiments. That's something you need to understand because it's not really contested.
The proper understanding isn't contested, but you don't have the proper understanding. How you measure doesn't determine the past, but it does determine what happens and what you end up seeing and measuring.
There are ways though for physicists to interpret this to get around seeming backwards in time causality...
Physicists don't have to do this because they interpret the experimental results correctly within the framework of quantum theory. You, on the other hand, have drawn a conclusion completely contrary to quantum theory simply because you've fallen in love with the idea of the present changing the past.
I strongly suggest before you keep bashing me that you take some time to get a handle on what is actually observed in these experiments.
Yeah, sorry about you feeling bashed, not intentional. My suggestion to you is to try understand the consensus view better, even if you don't accept it. You might find it has more to recommend it than you think, even if it doesn't support your hoped for transformation-of-the-past capability. Maybe you're right and one day we'll figure out that this is indeed possible, but there's very little in our current understanding of quantum behavior to indicate this.
--Percy

This message is a reply to:
 Message 168 by randman, posted 06-19-2006 4:09 PM randman has not replied

  
Percy
Member
Posts: 22505
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.4


Message 172 of 246 (323413)
06-19-2006 5:15 PM
Reply to: Message 169 by randman
06-19-2006 4:20 PM


Re: superluminal potentials still under debate
randman writes:
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.
And why did he not accept causality violations? You need to learn a bit more about the interpretations that avoid this somewhat obvious conclusion and also realize that some like Wheeler do talk about causality in a different way (in other words violating causality). Others like even PaulK here from his reading, presumably picked up from scientists, get around this by saying the past was indeterminate and so try to get around it that way.
I going to assume you're mischaracterizing PaulK's views and that he doesn't actually believe that obvious evidence of causality violations is gotten around by excuses about indeterminancy. This is just your caricature of his views.
Your misunderstanding in this regard is one of the reasons why Iblis mentioned information in regard to entanglement at one point. PaulK wasn't saying that scientists make an excuse. He was making a very real point about information. He was explaining to you that what you think is changing in the past is actually information you never really had.
Iblis seemed to be saying that the photon still takes all possible paths even though it appears to only take one path when we can determine that path. Imo, this is sort of the same thing as I am saying since the universe we live in as human beings would have a multitude of pasts, that appear or disappear depending on our observations.
What you are saying is by no stretch of the imagination anything like "sort of the same thing" as what Iblis is saying. That would be like saying being right is sort of the same thing as being wrong.
The correct view described by Iblis is that once observed, the "all paths" possibilities decohere into a single possibility, the one observed. This represents possibilities going away.
Your incorrect view holds that somehow some action in the present creates new possibilities in the past, and beyond that, you believe that this is the accepted view of mainstream science and that everyone else here just refuses to understand it. If I were you I'd look for a more likely theory than that you're right and everyone else is wrong.
--Percy

This message is a reply to:
 Message 169 by randman, posted 06-19-2006 4:20 PM randman has replied

Replies to this message:
 Message 175 by randman, posted 06-19-2006 6:24 PM Percy has replied

  
Percy
Member
Posts: 22505
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.4


Message 173 of 246 (323420)
06-19-2006 5:41 PM
Reply to: Message 170 by randman
06-19-2006 4:35 PM


Re: superluminality is a topic of research
randman writes:
Let's take your example as poor as it is and you acknowledge that.
Take two boxes and one marble. But the marble in one box. Take the boxes to opposite sides of the universe. Open a box. Instantly you know the contents of the other box, billions of light years away. Big deal.
NO NO NO NO NO NO NO!!!!
You've completely missed Cavediver's point. It isn't that this is a poor example of entanglement. It's that this isn't an example of entanglement at all! Not even close! In fact, it's misleading.
The big deal is that you instantly know the state of the other particle billions of light-years away, and the knowledge of that situation may well have been transferred from the box you have in front of you, but using this principle you can know something instantly about a box a billion light-years away.
I think this process can be manipulated to convey information.
This is almost too funny! Not only can entanglement not be used for superluminal communication, Cavediver's example of an incorrect analog for entanglement most certainly cannot be used for superluminal communication.
If you can devise a way to know something about something in a distant place, well, I think there is a potential to manipulate that process.
There is nothing in entanglement that allows you to know anything about a distant place. You can't even know if the distant particle has even be measured. All you can do is measure your particle and know that if and when they measure theirs, it will have the opposite spin.
The truth is information is transferred over space and time instantly all the time. Heck, when I read a history book, I am getting information about the past.
Omigod! It only gets better!
There are some interesting thought experiments you can think through to help you understand entanglement. For example, you give one entangled particle to a close friend who is traveling to a distant destination across the galaxy. You both have the same hobby of building ships in a bottle, but you won't be able to pursue this together while he's gone. Usually one of you makes the masts, sails and rigging while the other makes the main body of the ship, and you decide who does what by a random flip of a coin.
Your friend will be pretty busy on the way out and will only have time for ship-building on the way back, so you decide to use the entangled particles as a coin flip. When your friend reaches his destination he'll check the spin of his particle, and if it is positive spin then he'll build the masts, sails and rigging, and if it is negative spin he'll build the ship's body. You, here on earth, will check your particle, which will have opposite spin, and then you will also know which to portion to build.
So off he goes, you both check your particles a few years later when he arrives (he knows when he arrives, all you can do is check your particle according to his ETA), and you both begin building your respective parts of the ship. Then a few years after that he returns and lo and behold, you find that you've both built complementary parts of the ship, and as part of that night's celebration you assemble them and insert them in the bottle as a symbol of your long and enduring friendship.
Why is this not FTL communication?
--Percy

This message is a reply to:
 Message 170 by randman, posted 06-19-2006 4:35 PM randman has replied

Replies to this message:
 Message 177 by randman, posted 06-19-2006 6:36 PM Percy has replied
 Message 179 by cavediver, posted 06-19-2006 6:49 PM Percy has not replied

  
Percy
Member
Posts: 22505
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.4


Message 183 of 246 (323517)
06-19-2006 7:37 PM
Reply to: Message 175 by randman
06-19-2006 6:24 PM


Re: superluminal potentials still under debate
randman writes:
First off, you ought to reread what PaulK stated before assuming I am mischaracterizing his statements. This what he said:
No, my position is that at the quantum level the past is often not written in the first place. From this point of view the "delayed choice" experiments indicate that an indeterminate past can be forced into a determinate state - not that there was a determiante past which changed.
Uh, you better check your own coherence here. Clearly PaulK is not claiming that physicists viewed the experimental results as obvious evidence of causality breaking for which they sought an excuse in indeterminancy. That was your mischaracterization of his views. Another way of describing what you did is that you described his views while mixing in your own commentary without distinguishing which was which.
So let's take this further, along the path of a photon then, it may hit a spot due to circumstances that there is a means of registering the photon's path and so at that point, the photon in the past will have taken a single path. But later down the road, the means to determine which path the photon took could be erased or lost, and so the photon then, over the same stretch of space in the past, will have travelled in superposition and not a single path. In that manner, the past that we deal with does indeed demonstrably change.
The previous two paragraphs were fine, and the first part of this one is fine, too. Where you go wrong is in thinking there was a past that we knew that then changed. But we never knew that past. This is not a case of information we had that changed, but of information we never had. The lesson to be taken from the experiment isn't that causality is broken, but that you can't fool mother nature, who seems to know precisely whether an observation that actually yields information has taken place.
Whether someone knows about the path or not is not really germane to the discussion. In fact, the person that measures the photon when they can tell what it did will see the photon having taken only one path, and another person measuring the same photon but without the means even in principle of knowing from measurement what path the photon took, will see the same past as having shown the particle travel as a wave.
Well, that's a new one! Sounds dead wrong to me, like some weird combination of relativity and quantum theory, but I'll leave it to others to make informed comments.
And the quantum eraser experiment shows that this decoherence is not permanent. That's a key point you are missing here.
This is definitely wrong. For this to be true causality would have to be broken, and it's not.
--Percy

This message is a reply to:
 Message 175 by randman, posted 06-19-2006 6:24 PM randman has not replied

  
Percy
Member
Posts: 22505
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.4


Message 184 of 246 (323528)
06-19-2006 7:57 PM
Reply to: Message 177 by randman
06-19-2006 6:36 PM


Re: superluminality is a topic of research
randman writes:
There is nothing in entanglement that allows you to know anything about a distant place. You can't even know if the distant particle has even be measured. All you can do is measure your particle and know that if and when they measure theirs, it will have the opposite spin.
This is a contradiction. You admit you can know what a particle's spin is on the other side of the universe; hence you can know something about a distant place.
Say what? Are you even thinking before you type?
Similarly, you fail to realize harnessing the principle of entanglement is in it's infancy. You assume that such and such cannot be done, and ridicule that, but in reality, there are scientists working to see if it can be done all the time. A few years ago, Hawkings said time travel was impossible, and now says that though unlikely, it is possible.
Say what? Are you even reading before you type?
Remember me? I'm the guy who said we all look forward to scientific advances, but that it is important to make sure we plant our flag on solid ground and not in quicksand. I'm telling you not to grasp at the faintest hint of a scientific advance as if it were solidly established progress. By no stretch of the imagination can that be construed as telling science where it can and can't make progress.
Let me say this another way, because you seem to be having trouble grasping this point. What you are doing is finding slight indications (and even misinterpretations of counter-indications) of theories that you wish were true, and then you're claiming that these represent views solidly in the mainstream of science, and that we're all a bunch of dunderheads for telling you that you're wrong. And then you go beyond that and accuse us ridiculing scientific progress.
No one here is questioning what future scientific discoveries might bring. But it definitely is not an accepted view of the science that causality has been broken, and that's all we're telling you. We're not telling you we'll never discover that it's been broken. We're not telling you it's impossible for it to ever be broken. We're just telling you that your claim that science now accepts causality breaking is wrong. Dead wrong.
Right now, we don't really understand fully the mechanism of entanglement and so it is foolish to say that this mechanism cannot be used for such and such.
This gives me an opportunity to make my point yet another way. We're not saying we know that we'll never be able to harness entanglement for FTL communication. We're saying that it is not a view of science that this is possible. We all of us understand the principle of tentativity, and we know that current scientific views are open to change, and so we would never deign to do that. But we do happen to know what science thinks on this topic today, and it isn't anything like what you are claiming.
Lastly, what does superluminality have to do with my arguments in the OP?
If you don't want to talk about it, don't keep bringing it up. It was a side issue related to information until you brought up the ORNL paper and tried to argue that the possibility of superluminary communication was a widely accepted view, and you keep returning to the subject.
--Percy

This message is a reply to:
 Message 177 by randman, posted 06-19-2006 6:36 PM randman has replied

Replies to this message:
 Message 187 by randman, posted 06-19-2006 8:42 PM Percy has replied

  
Percy
Member
Posts: 22505
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.4


Message 190 of 246 (323688)
06-20-2006 1:13 AM
Reply to: Message 187 by randman
06-19-2006 8:42 PM


Re: superluminality is a topic of research
randman writes:
You guys are the ones that bring up superluminality, not me, percy.
Rather than pretend he didn't say this, or doesn't believe this, or trump up some unrelated BS about Paul Davies that has no relevance whatsoever, why don't you take a stab at explaining what you think Wheeler meant?
Remember, you're arguing for causality breaking. Where in your Wheeler quote do you see an argument for causality breaking?
The same is true of your Feynman quote. Where in that quote do you see an argument for causality breaking?
I think it's a mystery to everyone why you see arguments for causality breaking everywhere you look, but no one sees them but you.
It should tell you something that you can't find anyone anywhere making explicit statements that causality breaking has been demonstrated. I recall now that you went on and on a few months ago arguing that TalkOrigins misrepresented the two definitions of evolution, also something that only you could see. I think the support you find for your positions in material that actually provides no support is just some little habit you've somehow developed, and I'm not sure it makes any sense to try to raise evidence and rational arguments against it.
--Percy

This message is a reply to:
 Message 187 by randman, posted 06-19-2006 8:42 PM randman has replied

Replies to this message:
 Message 191 by randman, posted 06-20-2006 2:04 AM Percy has replied

  
Percy
Member
Posts: 22505
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.4


Message 197 of 246 (323719)
06-20-2006 3:17 AM
Reply to: Message 191 by randman
06-20-2006 2:04 AM


Re: Read Iblis' last post
randman writes:
These could be good discussions, if you treated them with respect and intellectual honesty.
I believe I made a suggestion earlier regarding references to people's honesty. Third time's a charm!
You've somehow acquired the false belief that I've been claiming I know what Wheeler's actual views on causality violations are. What I've said is that whatever Wheeler's actual views are, it is definitely not a view of mainstream science that causality violations have been demonstrated and are consistent with quantum theory.
A quick Google didn't reveal any helpful websites regarding what you've claimed about Wheeler. If you want to suggest one or two, I'll take a look. But to remind you once again, I'm just giving my interpretation of the views of modern science. If Wheeler had different views about causality violations then it looks to me like modern science has rejected them.
One thing I did find via Google was an essay called Quantum Philosophy by John Horgan, a science writer at Stevens Institute. It looks like many of the things you have been saying have come from there, like the claim that you can uncollapse a wave function. My own reading is that Horgan is confused about quantum theory in a manner similar to your own confusion, but I'll defer to Cavediver as to whether Horgan has actually got things wrong. I found I couldn't be quite sure because it seemed to be a combination of correct and incorrect information.
One thing the Google did tell me, though, is that there seems to be a wide variety of opinion among scientists about interpretations of quantum theory, and even greater variety about what might be discovered in the future.
--Percy

This message is a reply to:
 Message 191 by randman, posted 06-20-2006 2:04 AM randman has replied

Replies to this message:
 Message 199 by randman, posted 06-20-2006 3:23 AM Percy has not replied

  
Percy
Member
Posts: 22505
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.4


Message 198 of 246 (323720)
06-20-2006 3:20 AM
Reply to: Message 191 by randman
06-20-2006 2:04 AM


Re: Read Iblis' last post
I see your post has more than doubled in length since I began composing my reply. I'll have to look it over later.
--Percy

This message is a reply to:
 Message 191 by randman, posted 06-20-2006 2:04 AM randman has replied

Replies to this message:
 Message 201 by randman, posted 06-20-2006 3:27 AM Percy has not replied

  
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