# Point Particles
**URL:** https://boards.straightdope.com/t/point-particles/792899
**Category:** Factual Questions
**Created:** [August 6, 2017, 9:26am UTC](https://boards.straightdope.com/t/point-particles/792899 "2017-08-06T09:26:51Z")
**Posts on this page:** 15
**Page:** 2
### Author:  [@abashed](https://boards.straightdope.com/u/abashed)
#### Post date: [August 7, 2017, 5:38pm UTC](https://boards.straightdope.com/t/point-particles/792899/21 "2017-08-07T17:38:26Z")
> [@Francis\_Vaughan](#):
>
> Yes, in that there is subtlety. But the person that wrote the article had no idea what that subtlety was. They pure and simple got it wrong. There is nothing subtle about that. QM does not say that reality does not exist before it is measured. It never has, and this experiment does not change things.
With all due respect I think you might be a bit confused here. QM does not say there is absolutely nothing to measure beforehand, of course not. That would mean we can create reality from nothing! It says we can never predict exactly the outcome of a measurement. It’s probabilities, not certainties.
> [@](#):
>
> Einstein railed against the idea that there was pure randomness in QM. He won the Nobel prize for contributing one of the most important early components of QM. I find it remarkable how few people know that he didn’t win a Nobel for relativity (either special or general) but did win it for the photoelectric effect. [Nitpick. Newton’s ideas about a clockwork universe were not in any way challenged by relativity. Relativity continues to allow for a perfectly deterministic universe, (except perhaps when we get to issues of information deletion in black holes.)] There remains a rump group of physicists who adhere to ideas of “hidden variables”. They still believe in a clockwork universe. Underneath it all, I suspect Roger Penrose is one such.
I know but QM has been the most successful theory in the history of physics so the skeptics have a lot of explaining to do. Thus far they have been unsuccessful at supplanting QM.
> [@](#):
>
> The way we think the universe runs is for physicists quite logical, and so far rather a lot of what we know is covered rather well by QM and GR. We know our knowledge is not complete. But that understanding does not behove us to abandon everything we know so far. Sure, much of modern physics is counter-intuitive, but this does not suddenly let us say that our understanding of reality can be dismissed.
>
> You talk of reconciling classical and quantum worlds as if this was a problem. It isn’t. Classical physics is understood to be wrong. It is however also very useful. Physicists use classical approximations wherever they think they can get away with them because it simplifies the mathematics. It simplifies the mathematics **a lot**. You will hear of semi-classical models. Basically using QM or GR where it is needed, and keeping as much classical as possible to stop the maths blowing up.
All it really means is we have an incomplete picture of reality. That is nothing new and will continue to be so.
> [@](#):
>
> Where you will get discussion is about the interpretations of QM, and I suspect this is where you are getting a lot of the distorted ideas about the nature of QM and how it is interpreted from. This is where you get a lot of popular coverage of QM. People writing about the mystical elements of how QM might involve parallel universes (it doesn’t, that is a misunderstanding of the many worlds interpretation), pure randomness, hidden variables, pilot waves, and so on.
You do, however, have to provide solutions to the bizarreness of QM and people have been forced to erect speculative ideas because conventional ones simply won’t work. Sometimes we have to admit that our old ideas no longer serve their purpose. The universe is much smarter than us.
> [@](#):
>
> The entire EPR paradox is based in, as I said, decades old theory. Experiments have shown that, well, the experiment does actually do what it says on the tin. This tells us, not as EP&R perhaps hoped, that QM is wrong, but rather that there is a core bit of reconciliation remaining. The fact that the theory is quite clear that information cannot be send at superluminal speeds, consistent with relativity, is a very big deal.
Hmmm…okay true BUT in an odd kind of way the fact that we have shown entangled particles are in ‘instant’ touch with one another is a form of information in that we, as ‘observers’, possess. Whether we can go on to develop that remains to be seen. But I know what you mean and it seems to show there are ‘layers’ of reality’. Spacetime may be but one of many.
---
### Author:  [@Francis\_Vaughan](https://boards.straightdope.com/u/Francis_Vaughan)
#### Post date: [August 7, 2017, 6:22pm UTC](https://boards.straightdope.com/t/point-particles/792899/22 "2017-08-07T18:22:26Z")
> [@abashed](#):
>
> In a way you can because it is the fact that the experimenter is conscious of the information that seems to be causing the effect. Don’t ask me how because it seems very mysterious but I come back to the fact that we, as observers, seem to play a vital role in these results and it may be consciousness itself that is causing such anomalies.
That consciousness causes the collapse of the state vector has been one possible idea that goes back decades. It seems to be the one the mystics always focus on and claim some sort of deep woo about. You seem to have been influenced by this.
> [@](#):
>
> In fact, this seems quite logical to me because how could a quantum object be ‘aware’ of what the experiment is doing? It does seem to come back to human intervention. I think it’s probably as well to point out that
However we conduct these experiments with machines and computers. We just get a printout of the results on a computer screen. You would have to suggest that the entire environment, right through the experimental apparatus, the detectors, the computer, the computer storage system, the network, the final PC the result are viewed on, are all part of this conciousness. And you have to cope with the fact that there is more than one conscious being interested in the results.
> [@](#):
>
> we do not really understand what consciousness is so I don’t think we should automatically poo-poo this idea.
No we don’t, but you don’t get to invent new physics by saying, we don’t understand X, and we don’t understand Y, therefore X = Y.
> [@](#):
>
> You don’t seem to understand that a particle can become a wave by manipulating the experiment in the particle’s future, thereby, causing a retroactive effect.
I don’t think you get what the experiment is, or what is going on. Nor indeed do you seem to have grasped much of what has been said to you in other threads about this. A particle does not become a wave, nor does a wave become a particle. There is this popular idea that there is some sort of mystical duality, something not helped by some scientists trying to explain to the public in simple terms.
> [@](#):
>
> Remember, the particle has already been set as a particle and ordinarily you would expect it to remain so but this has been disproved.
This actually makes no sense. You can’t “set” a particle to be a particle. It is what it is. And there is no “remaining so”. It behaves as it does, as described by well understood mathematics.
> [@](#):
>
> Are you saying that when the particle comes into existence it isn’t real?
I thought that was you.
> [@](#):
>
> If not the the particle is real and can be made to change its ‘reality’ by a future event.’
No it can’t, and again, these experiments do not show that this is the case. It is much more subtle. The problem is that you are imposing a classical idea about causality, state and time onto the experiment, and thus misunderstanding. In fact you are committing exactly the sin you accuse everyone else of. You need to let go of your human level ideas and intuition of time and causality and state and understand just what is being said. Conventional mysticism isn’t going to help anyone. The way QM works is not what you think. As Neils Bohr said: “Anyone who is not shocked by quantum theory has not understood it.”
> [@](#):
>
> Do we really know what space and time is anyway? The answer is probably no.
No, but we have a very good, and highly verified idea of how it works. It is incomplete, and it is incomplete in exactly the area of EPR. But again, the experiment you cite is a validation of the current known science, yet you seem to continue to claim the exact opposite. We know there is a question about causality. But no experiments answer it. They just confirm the gap in knowledge.
[https://www.instagram.com/p/BTMCON2hPmZ/?taken-by=tomgauld](https://www.instagram.com/p/BTMCON2hPmZ/?taken-by=tomgauld)
---
### Author:  [@Chronos](https://boards.straightdope.com/u/Chronos)
#### Post date: [August 7, 2017, 7:34pm UTC](https://boards.straightdope.com/t/point-particles/792899/23 "2017-08-07T19:34:04Z")
Note, by the way, that hidden variables have _not_ actually been ruled out by experiment. The EPR experiment means that you have to give up something that seems like it ought to be intuitively true, but there are multiple choices for what to give up, and hidden variables are only one of them. You can also, for instance, instead give up locality, and construct a perfectly good (as in, as good as any other model of quantum mechanics) nonlocal hidden variable model.
Given that these models are all equally accurate (in all cases, they all predict the same actual results), it’s largely a matter of philosophical taste which one (if any) you prefer.
---
### Author:  [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)
#### Post date: [August 7, 2017, 8:06pm UTC](https://boards.straightdope.com/t/point-particles/792899/24 "2017-08-07T20:06:02Z")
> [@Francis\_Vaughan](#):
>
> However we conduct these experiments with machines and computers. We just get a printout of the results on a computer screen. You would have to suggest that the entire environment, right through the experimental apparatus, the detectors, the computer, the computer storage system, the network, the final PC the result are viewed on, are all part of this conciousness. And you have to cope with the fact that there is more than one conscious being interested in the results.
IIRC if you do the double-slit experiment and put a detector near one of the slits to see which slit the particle goes through the interference pattern disappears. The other parts of the experiment do not seem to stop an interference pattern from forming but the thing that will tell you which slit the particle goes through does.
No need for a living observer.
The quantum eraser experiment also seems to have no need for a living observer yet can still change results.
It’s hard avoiding the woo with results like that.
---
### Author:  [@abashed](https://boards.straightdope.com/u/abashed)
#### Post date: [August 8, 2017, 7:39am UTC](https://boards.straightdope.com/t/point-particles/792899/25 "2017-08-08T07:39:55Z")
> [@Chronos](#):
>
> Note, by the way, that hidden variables have _not_ actually been ruled out by experiment. The EPR experiment means that you have to give up something that seems like it ought to be intuitively true, but there are multiple choices for what to give up, and hidden variables are only one of them. You can also, for instance, instead give up locality, and construct a perfectly good (as in, as good as any other model of quantum mechanics) nonlocal hidden variable model.
>
> Given that these models are all equally accurate (in all cases, they all predict the same actual results), it’s largely a matter of philosophical taste which one (if any) you prefer.
Unfortunately there is no evidence for hidden variables, local or not.
---
### Author:  [@abashed](https://boards.straightdope.com/u/abashed)
#### Post date: [August 8, 2017, 7:41am UTC](https://boards.straightdope.com/t/point-particles/792899/26 "2017-08-08T07:41:44Z")
> [@Whack-a-Mole](#):
>
> IIRC if you do the double-slit experiment and put a detector near one of the slits to see which slit the particle goes through the interference pattern disappears. The other parts of the experiment do not seem to stop an interference pattern from forming but the thing that will tell you which slit the particle goes through does.
>
> No need for a living observer.
>
> The quantum eraser experiment also seems to have no need for a living observer yet can still change results.
>
> It’s hard avoiding the woo with results like that.
You are forgetting that at some point a living observer has to look.
---
### Author:  [@Francis\_Vaughan](https://boards.straightdope.com/u/Francis_Vaughan)
#### Post date: [August 8, 2017, 7:58am UTC](https://boards.straightdope.com/t/point-particles/792899/27 "2017-08-08T07:58:15Z")
> [@abashed](#):
>
> You are forgetting that at some point a living observer has to look.
Why does this matter?
What do you define as living?
Something that I think gets missed about these experiments in such discussions. There is nothing special about the experiments except that they try to isolate a particular part of the theory so it can be observed. But the theory predicts that every single QED interaction that happens anywhere and any time in the entire universe is bound by the same rules. All we are doing is teasing out a particular component of those rules so we can measure it.
But the rules of QED only work when every possible set of interactions is allowed for. This is a really important point. QED includes all the weird behaviour, and if you remove it from the theory, the numbers don’t match reality. You get the wrong numbers, and it predicts that all manner of mundane things are different to how they are. What this tells you is that there is nothing special about your experiment and its living observer. Every chemical reaction, every photon travelling though the universe, the vast majority of things you can conceive of are governed by these rules in a manner that affects their basic operation. The Earth has existed for billions of years without life, but the chemistry worked, and the stars have shined for billions of years, all governed by the same laws. We didn’t need an observer to make the physics work then. Why should we now?
---
### Author:  [@abashed](https://boards.straightdope.com/u/abashed)
#### Post date: [August 8, 2017, 8:45am UTC](https://boards.straightdope.com/t/point-particles/792899/28 "2017-08-08T08:45:22Z")
> [@Francis\_Vaughan](#):
>
> That consciousness causes the collapse of the state vector has been one possible idea that goes back decades. It seems to be the one the mystics always focus on and claim some sort of deep woo about. You seem to have been influenced by this.
> However we conduct these experiments with machines and computers. We just get a printout of the results on a computer screen. You would have to suggest that the entire environment, right through the experimental apparatus, the detectors, the computer, the computer storage system, the network, the final PC the result are viewed on, are all part of this conciousness. And you have to cope with the fact that there is more than one conscious being interested in the results.
All that machines are doing is conveying what has already been established by previous experiments because once a particular experimental situation has been performed and results observed it simply provides the same, repeatable data. The point here is we are talking about ‘information’ and information can take various forms.
> [@](#):
>
> No we don’t, but you don’t get to invent new physics by saying, we don’t understand X, and we don’t understand Y, therefore X = Y.
Well, no, but if you have better solutions please feel free to air them here. Earlier you were criticising some of the well known interpretations of QM but simply saying ‘we don’t know’ is not very constructive.
> [@](#):
>
> I don’t think you get what the experiment is, or what is going on. Nor indeed do you seem to have grasped much of what has been said to you in other threads about this. A particle does not become a wave, nor does a wave become a particle. There is this popular idea that there is some sort of mystical duality, something not helped by some scientists trying to explain to the public in simple terms.
I’m shocked that you don’t seem to have heard of the duality of light. Light can be either a wave or particle depending on how you measure it. The language you are using is a bit befuddling. A particle is both a wave and a particle at the same time but only resolves to one or the other upon measurement. You’re making it look as though we have the power to ‘create’ a particle or wave and in a way we do but you have to be careful how you use language here.
> [@](#):
>
> This actually makes no sense. You can’t “set” a particle to be a particle. It is what it is. And there is no “remaining so”. It behaves as it does, as described by well understood mathematics.
Again, language confuses. What I meant by ‘set’ is to make a measurement which combines the potential of a quantum object to ‘collapse’ to a specific state.
I
> [@](#):
>
> No it can’t, and again, these experiments do not show that this is the case. It is much more subtle. The problem is that you are imposing a classical idea about causality, state and time onto the experiment, and thus misunderstanding. In fact you are committing exactly the sin you accuse everyone else of. You need to let go of your human level ideas and intuition of time and causality and state and understand just what is being said. Conventional mysticism isn’t going to help anyone. The way QM works is not what you think. As Neils Bohr said: “Anyone who is not shocked by quantum theory has not understood it.”
>
> No, but we have a very good, and highly verified idea of how it works. It is incomplete, and it is incomplete in exactly the area of EPR. But again, the experiment you cite is a validation of the current known science, yet you seem to continue to claim the exact opposite. We know there is a question about causality. But no experiments answer it. They just confirm the gap in knowledge.
>
> [Tom Gauld on Instagram: "For New Scientist. #tomgauld #cartoon #science #dinosaurs #jurassicpark"](https://www.instagram.com/p/BTMCON2hPmZ/?taken-by=tomgauld)
Well, since words usually refer to classical ideas I have little choice, but you have to take these things as analogies. Remember, however, that whatever way we choose to represent quantum behaviour it is always going to be analogous since we can never be directly aware of what quantum objects are. Even mathematics is a set of symbols that represent analogies with with to pattern behaviour. It’s _patterns_ of phenomena that are of interest, whether or not we can really ever know what they really are.
All you really seem to be saying here is that QM is strange and we don’t know why, which is correct. And ‘the gap in knowledge’ you mention does not mean we are able to find solutions that avoid the role of the observer. Look at the facts: an experimenter does something in an experiment that seems to violate causality. Now, how can a quantum object ‘know’ what is being done in a sophisticated scientific experiment? Obviously it can’t because it has no ‘knowledge.’ So what is the commonality here? The answer is the knowledge of the human experimenter, therefore it is the ‘information’ generated by the experiment that is acting to produce the observed result. What you are not seeing is the role of knowledge in measuring phenomena, whether examining stars, black holes, planets, etc., or the tiny world of atoms and sub-atomic particles. These things are only as real as our human representations of them are real. You are wedded to the idea of a ‘concrete’ externally existing ‘reality’ out there but this gets you nowhere in the end since we can only examine what we can examine within our own nature. Words, mathematics, images and so on are merely our way of interacting with the world and many people seem to think there is ‘stuff’ which exists quite independently of our observations and measurements which would carry on, regardless of whether we existed or not. This is a profound misunderstanding of reality and I think you may have been subject to the misguided precepts of classical paradigms.
---
### Author:  [@abashed](https://boards.straightdope.com/u/abashed)
#### Post date: [August 8, 2017, 9:52am UTC](https://boards.straightdope.com/t/point-particles/792899/29 "2017-08-08T09:52:08Z")
> [@Francis\_Vaughan](#):
>
> Why does this matter?
> What do you define as living?
>
> Something that I think gets missed about these experiments in such discussions. There is nothing special about the experiments except that they try to isolate a particular part of the theory so it can be observed. But the theory predicts that every single QED interaction that happens anywhere and any time in the entire universe is bound by the same rules. All we are doing is teasing out a particular component of those rules so we can measure it.
>
> But the rules of QED only work when every possible set of interactions is allowed for. This is a really important point. QED includes all the weird behaviour, and if you remove it from the theory, the numbers don’t match reality. You get the wrong numbers, and it predicts that all manner of mundane things are different to how they are. What this tells you is that there is nothing special about your experiment and its living observer. Every chemical reaction, every photon travelling though the universe, the vast majority of things you can conceive of are governed by these rules in a manner that affects their basic operation. The Earth has existed for billions of years without life, but the chemistry worked, and the stars have shined for billions of years, all governed by the same laws. We didn’t need an observer to make the physics work then. Why should we now?
But how did the universe know it existed without an observer?
---
### Author:  [@Chronos](https://boards.straightdope.com/u/Chronos)
#### Post date: [August 8, 2017, 2:02pm UTC](https://boards.straightdope.com/t/point-particles/792899/30 "2017-08-08T14:02:01Z")
> [@](#):
>
> Unfortunately there is no evidence for hidden variables, local or not.
And in fact there can’t be. As I said before, the interpretations of quantum mechanics which include nonlocal hidden variables give exactly the same results as the interpretations which do not include them. Asking which interpretation is “true” is therefore not a question for science.
> [@](#):
>
> But how did the universe know it existed without an observer?
Why did it need to?
---
### Author:  [@DPRK](https://boards.straightdope.com/u/DPRK)
#### Post date: [August 8, 2017, 2:48pm UTC](https://boards.straightdope.com/t/point-particles/792899/31 "2017-08-08T14:48:07Z")
Not quite a General Answer, but I have never found quantum mechanics spooky or strange. I find it logical, elegant, and beautiful. There: you can relax now; all is right with the world.
---
### Author:  [@Francis\_Vaughan](https://boards.straightdope.com/u/Francis_Vaughan)
#### Post date: [August 8, 2017, 2:55pm UTC](https://boards.straightdope.com/t/point-particles/792899/32 "2017-08-08T14:55:14Z")
> [@abashed](#):
>
> But how did the universe know it existed without an observer?
This starts to get close to a version of the strong anthropic principle. That the reason humankind (or any intelligence) exists is so that the universe can have an observer. This becomes revealed truth, ie religion. The reasoning soon becomes circular, and pointless.
You also end up with a form of solipsism. The reason you exist is so that the universe can. None of these ideas have anything going for them, and certainly don’t have any physics, or indeed logic to back them up.
And if the universe **knows** it exists, it is clearly conscious, and thus can observe its own existence. It thinks therefore it is. It becomes a solipsist universe. We become irrelevant.
---
### Author:  [@Exapno\_Mapcase](https://boards.straightdope.com/u/Exapno_Mapcase)
#### Post date: [August 8, 2017, 3:02pm UTC](https://boards.straightdope.com/t/point-particles/792899/33 "2017-08-08T15:02:18Z")
> [@abashed](#):
>
> All you really seem to be saying here is that QM is strange and we don’t know why, which is correct. And ‘the gap in knowledge’ you mention does not mean we are able to find solutions that avoid the role of the observer. Look at the facts: an experimenter does something in an experiment that seems to violate causality. Now, how can a quantum object ‘know’ what is being done in a sophisticated scientific experiment? Obviously it can’t because it has no ‘knowledge.’ So what is the commonality here? The answer is the knowledge of the human experimenter, therefore it is the ‘information’ generated by the experiment that is acting to produce the observed result. What you are not seeing is the role of knowledge in measuring phenomena, whether examining stars, black holes, planets, etc., or the tiny world of atoms and sub-atomic particles. These things are only as real as our human representations of them are real. You are wedded to the idea of a ‘concrete’ externally existing ‘reality’ out there but this gets you nowhere in the end since we can only examine what we can examine within our own nature. Words, mathematics, images and so on are merely our way of interacting with the world and many people seem to think there is ‘stuff’ which exists quite independently of our observations and measurements which would carry on, regardless of whether we existed or not. This is a profound misunderstanding of reality and I think you may have been subject to the misguided precepts of classical paradigms.
None of this is true, to my understanding. QM has a number of interpretations. They are mathematically equivalent so they all are equally “true” or equally “false” which is saying that the numbers work or don’t work. Most everything works.
“Observation” is important only in the Copenhagen interpretation. This is sometimes given as “consciousness” and then elevated to human consciousness, but this is strenuously argued in the community. Most modern physicists define observation in non-human, non-living ways. There are [bunches of other interpretations](https://en.wikipedia.org/wiki/Interpretations_of_quantum_mechanics) that avoid observation as a mechanism altogether.
Stuff does exist independently from us. Always has unless you believe that the universe sprang into existence the moment the first human gazed out onto the stars. That’s pure crackpottism. Reality doesn’t care about humans or lifeforms in any way.
---
### Author:  [@digs](https://boards.straightdope.com/u/digs)
#### Post date: [August 8, 2017, 6:42pm UTC](https://boards.straightdope.com/t/point-particles/792899/34 "2017-08-08T18:42:48Z")
> [@abashed](#):
>
> But how did the universe know it existed without an observer?
Is that a serious question? Come now…
> [@DPRK](#):
>
> Not quite a General Answer, but I have never found quantum mechanics spooky or strange. I find it logical, elegant, and beautiful. There: you can relax now; all is right with the world.
I did give a sigh of relief… Whew, a random smartypants says it’s okay (all the way down).
---
### Author:  [@Colibri](https://boards.straightdope.com/u/Colibri)
#### Post date: [August 8, 2017, 6:53pm UTC](https://boards.straightdope.com/t/point-particles/792899/35 "2017-08-08T18:53:31Z")
> [@digs](#):
>
> Is that a serious question? Come now…
Given the OPs responses in this thread, it’s obvious that his original question was not serious. I’m going to close this.
Colibri
General Questions Moderator
[Previous page](https://boards.straightdope.com/t/point-particles/792899.md?page=1)