I What if there were no observers?

SephQ
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If there were no observers, nothing that could measure, what would happen?
I’m new to quantum physics, and I probably don’t understand a lot of things. But there is one question I wanted to ask:

What would happen if there were no observers? Nothing that could measure?

(Edit) After doing a little bit of digging, apparently a thing doesn’t need to be observed to exist, so that helps :D

Still wanna know if anything else would happen if there were no observers though

Best regards,
Seph :P
 
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This really should be in interpretations of QM.

I don't think Quantum theory is even defined without at least one observer.
 
I mean the wave function will never collapse...
 
mad mathematician said:
I mean the wave function will never collapse...
Wave function collapse is only an interpretation of the mathematics of QM. It's not a physical process.
 
SephQ said:
TL;DR Summary: If there were no observers, nothing that could measure, what would happen?

I’m new to quantum physics, and I probably don’t understand a lot of things. But there is one question I wanted to ask:

What would happen if there were no observers? Nothing that could measure?

(Edit) After doing a little bit of digging, apparently a thing doesn’t need to be observed to exist, so that helps :D

Still wanna know if anything else would happen if there were no observers though

Best regards,
Seph :P
Do you mean without any conscious observers?

QM describes the laws of nature without the need for conscious observers. The early universe evolved without conscious life.
 
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PeroK said:
Wave function collapse is only an interpretation of the mathematics of QM. It's not a physical process.
What is a physical process? Is every sort of measurement considered a physical process?
 
PeroK said:
Do you mean without any conscious observers?

QM describes the laws of nature without the need for conscious observers. The early universe evolved without conscious life.
no, i mean with 0 ways of measuring, conscious or non-conscious. no robots, human, animals, plants type of stuff.

cause that way the entire world should be in uncertainty or smth
 
SephQ said:
no, i mean with 0 ways of measuring, conscious or non-conscious. no robots, human, animals, plants type of stuff.

cause that way the entire world should be in uncertainty or smth
There would still be the Big Bang, nucleosynthesis, star and galaxy formation etc. That must all happen. A combination of QM and GR describes the evolution of the universe.
 
mad mathematician said:
What is a physical process? Is every sort of measurement considered a physical process?
Star formation is a physical process, for example.
 
  • #10
SephQ said:
TL;DR Summary: If there were no observers, nothing that could measure, what would happen?
...
Still wanna know if anything else would happen if there were no observers though
My two cents (I'm not an expert in QM):
The term "observer" in QM is tricky. Any interaction that gives a result is an "observer". It doesn't matter if a measurement is taken or if a human observes it.
 
  • #11
PeroK said:
There would still be the Big Bang, nucleosynthesis, star and galaxy formation etc. That must all happen. A combination of QM and GR describes the evolution of the universe.
But if one by observer, means any system, ie any matter. Then to say "there is no observers" would seems the same as to suggest that is not yet matter.

So depending on interpretations, one answer to the thread-question might be the Big Bang.

But this generalisation of "observers" to non-macroscopic systems, is not allowed by current theory. It requires a macroscopic context (observing context) to be constructed. Perhaps once we have a unified measurement theory of all forces, including that of a evolving spacetime we can have a better answer and unification also of measurement processes and physical processes, and matter and observers.

But until then, I would say that QM as it stands makes no conceptual sense without a macroscopic observer. It can not be defined. Perhaps mahtematically or fictionally, but not operationally and experimentally.

So I would say no observer => no Quantum mechanics(as it stands today)
Generalized observers or the limit of no observer, likely requires a new theory to make sense.

/Fredrik
 
  • #12
I would note that, as a sort of "lies to children" answer, there were no living observers for the first 8 billion years of the universe and it existed just fine.

It's not the most scientifically informative of answers QM-wise, but it puts the period on the answer to the OP's question.
 
  • #13
mad mathematician said:
This really should be in interpretations of QM.
And now it is.
 
  • #14
SephQ said:
no, i mean with 0 ways of measuring, conscious or non-conscious. no robots, human, animals, plants type of stuff.

cause that way the entire world should be in uncertainty or smth
No, that way there would be no world at all. Something is always present in the universe, and that in itself is enough for there to be "observers" in the sense that matters for QM--things that can interact with other things and allow decoherence to take place.

Whether that results in "wave function collapse" depends on which interpretation of QM you adopt, as has already been commented.
 
  • #15
Fra said:
But if one by observer, means any system, ie any matter. Then to say "there is no observers" would seems the same as to suggest that is not yet matter.

So depending on interpretations, one answer to the thread-question might be the Big Bang.
No, it isn't.

The "Big Bang" in the sense of an initial singularity is not part of the universe at all.

The "Big Bang" in the sense of the hot, dense, rapidly expanding state that is the first state of our universe of which we have reasonably good evidence, was not the "beginning"; there was "stuff" before it (the most likely prospect for what "stuff" at present is some kind of inflationary model).

Neither of these supports your claim.

Fra said:
this generalisation of "observers" to non-macroscopic systems, is not allowed by current theory.
The post you responded to talked about Big Bang nucleosynthesis and galaxy and star formation. Those are macroscopic processes.
 
  • #16
FWIW, my take is that if there were no experimenters there would be no experiments. An experimenter is important because they have to decide what experiment they would like to build, find the money for the parts they need and permission to use lab space, build and debug the apparatus, then they turn on the power, and ...
it won't make a difference to the statistics of the datasets that the experiment collects —likely at GHz rates, which is faster than I or anyone else can decide anything— whether the experimenter (or an observer) is in the room or, more likely, having a coffee in the next room or in another country.
When the experiment has finished, after minutes or months, the experimenter's choices become important again. Computer programs to analyze Terabytes of data have be written, an article has to be written and submitted, and the experimenter has to decide what experiment they would like to build next.

One important distinction here is, I think, that of time scale. People can change their surroundings on minutes to decades timescales, but not on timescales significantly shorter than a second.
Another important distinction —again, I think— is that I take "statistics of datasets" as central, whereas the axioms of QM always begin with "properties of particles". That is a difference to think on — or you could search on YouTube for "A Dataset & Signal Analysis Interpretation of Quantum Mechanics" (a talk to students from two weeks ago) or for "A Dataset & Signal Analysis Interpretation of Quantum Field Theory" (a talk to the Oxford Philosophy of Physics Seminar from six months ago).
 
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  • #17
Peter Morgan said:
if there were no experimenters there would be no experiments. An experimenter is important because they have to decide what experiment they would like to build
While this is surely true (one might say self-evidently true) I'm not sure how it informs the discussion. The universe got on grandly for 8 billion years before observers - let alone experimenters - came along.
 
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  • #18
PeterDonis said:
The "Big Bang" in the sense of an initial singularity is not part of the universe at all.
True, as especially in GR "the universe" ~ our 4D manifold with a metric etc, so I agree. In this definition, from whatever this manifold was emergent from < planck times, is thus not part of the universe.

But I didn't mean to use the term so precisely, I was rather referring to "big bang" loosely as the origin of things (of which alot isn't knonwn), even contemplating was possibly before the 4D manifold, like in string theory for example.

Of course we don't know what happens there at all, but I think it seems reasonable to think that at some point near the breakdown of current models, the "candidates" of material observers, should break down as well as what could possibly be stable? So it seems questionable under most definitions to think that there are any non-trivial observers back here. That was my suggestion.

PeterDonis said:
The post you responded to talked about Big Bang nucleosynthesis and galaxy and star formation. Those are macroscopic processes.
I could be wrong, but interpreted the OP to consider "observers" that are not just biological, but any physical system. This is why I associated not just to before there was plants on earth, but before there was well defined macroscopic systems with spacetime relations.

/Fredrik
 
  • #19
Thanks for everyone’s replies! (Still gonna keep this thread open cause it seems like there can still be more to it)

Just to clear the question up:
Fra said:
I could be wrong, but interpreted the OP to consider "observers" that are not just biological, but any physical system.
Yes, I did consider “observers” as to be any physical system that can cause interactions.


But to sum it up for what i’ve seen (which may or may not be wrong):
1. Without observers, the world can still exist just fine. Observers do not play a role in the development of the universe.
2. QM simply describes the world under the circumstance that there is a observer.

I think that would be a good enough summary of my question, but feel free to give more ideas! I’ll try to check often to learn more :D

Best regards,
Seph :3
 
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  • #20
DaveC426913 said:
While this is surely true (one might say self-evidently true) I'm not sure how it informs the discussion. The universe got on grandly for 8 billion years before observers - let alone experimenters - came along.
My thinking here is that in the context of the Quantum Interpretations and Foundations Forum and a question "What if there were no observers?", it is appropriate to ask whether the idea of an "observer" is a good basis for thinking about physics. It seems that there has been a century-long discussion in the physics and philosophy literature (and in almost every popular physics forum) about just what an observer is and what they do, to no common agreement. What you've just said is, I think, that something about the idea of an experimenter and their various relationships with an experiment is "even self-evidently true", which is in stark contrast with almost anything that has ever been said about an observer.
I suggest there's a kind of Shut-Up-And-Calculate simplicity to the idea of an experimenter that there is not for the idea of an observer. Questions about what an observer is&does won't go away for philosophy, but I think they can be sidestepped for physics and I think that is helpful for physics. I suppose most working physicists don't often ask what an observer is&does, whereas they are almost always thinking about experiments and how to make their favorite experiment happen.
As to what an experimenter is&does, it has seemed to me that differences between time- (and length- and action-)scales are important: for seconds to Gigaseconds, for example, the experimenter can work towards rather close control of an apparatus and statistics of its datasets, but for much smaller than seconds an experimenter's control of details becomes progressively more tenuous.
You're right that on its own this doesn't help physics. I have been developing it, however, as a small part of a larger project to rethink the relationship between classical and quantum physics, for both of which I think the idea of an experiment includes an idea of datasets and analysis of those datasets. If you have time to look at either of the two videos that I mention above, you can discover what other ideas I find helpful to the project of getting out of the box that has been created by ideas like that of an "observer" (because most people won't have time, I've attached the PDF of the slides for the more recent talk I mentioned above, at a small college you won't have heard of in India, Bhadrak, a hundred miles from Kolkata, where the Head of the Physics department worries a lot about the idea of an observer (Dean Radin was also on their program for India's National Science Day) but Rajat is very open-minded.)
Anyway, kudos for replying. People on PF mostly ignore my comments here.
 

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  • #21
I have to read up upon the discussions we had years ago, I appreciated your emphasis on the signalprocessing, but I don't remember where we diverged. Don't remember if I asked you about this before but...

Peter Morgan said:
that something about the idea of an experimenter and their various relationships with an experiment is "even self-evidently true", which is in stark contrast with almost anything that has ever been said about an observer. I suggest there's a kind of Shut-Up-And-Calculate simplicity to the idea of an experimenter that there is not for the idea of an observer.
...
I suppose most working physicists don't often ask what an observer is&does, whereas they are almost always thinking about experiments and how to make their favorite experiment happen.
Have you tried to put your ideas in the context of predictive autoencoders? It seems to me it would be a nice mate with the idea of processing of "datasets". Ie. the predictive autoencoder (which is is tempting to call "observers") registers input, compresses data to respect memory constraints, retains the presumed interesting patterns. And from this compressed code predictions of the future follow (via some model; and pinpointing this model is essentially the problem of finding the hamiltonian).

Normal autoencodres is commong technology in digital soundprocessing, predictive encoders does not compress and reconstruct, but it compresses and and predicts with future stats in mind.

This would get us away from fictive "ensembles". Instead one predicts future sequence from a specific history. So no ensembles needed. This would make sense both for smaller "observers" and experimental human context. The difference is the memory and computational capacity the "autoencoder" has.

QM as it stands is formulates as if memory and processing is never limiting.

But "what if" the explanation to why nature entertains non-commutative encodings, lies precisely in that it is more efficient. Then we will not see it until we acknowledge the physical limitations of "observation".

This is why I think the observer concept is more central than ever.

So I'm curious to hear if you have put your idea in this context?

Edit after skimming more:

1) on page 3 in your slide you write "Something in a theory should generate expected averages etc for future datasets"; this is exactly the concept of an predictive autoencoder.
Seen as a deep learning autoencoder, the "extras" are in the hidden layers, then are "hidden from direct observer" but still real, and possible "inferrable", even not as an "observable".

2) page4: "what people do and not do" is also something one could abstractly think of as the reinfored training and evolutionary adjustments of the "hiddenstructure" of hte autoencoder. So I argue thta one can think that even an "abstract observer" does all this! But in a "different langauge", at lower level.
(any my question was if you like or do not like these associations and perspective to your things).

3) Related reference: "This shows that the learning dynamics of a neural network can indeed exhibit approximate behaviors described by both quantum mechanics and general relativity. We also discuss a possibility that the two descriptions are holographic duals of each other." - Vitaly Vanchurin, The world as a neural network. This duality is exactly what the external vs internal view are supposed to be! They are not in conflict, its dual views but they have different advantages.

4) Another reference Deep Learning and AdS/CFT, again this is "datadriven", and processing driven, not using fictive ensembles or infinite statistics.

/Fredrik
 
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  • #22
A particle doesn't "measure" or "observe" another particle, a particle simply has other particles or systems of particles around it. It "interacts" with them or not based on certain laws; without any consciousness involved. ((That system of particles may correspond to an object for which we have a classical description, but that's another topic))

The universe exists without the need for observers or measurement device to exist, but it could not exist without having existed interactions.
 
  • #23
Fra said:
Have you tried to put your ideas in the context of predictive autoencoders? It seems to me it would be a nice mate with the idea of processing of "datasets". Ie. the predictive autoencoder (which is is tempting to call "observers") registers input, compresses data to respect memory constraints, retains the presumed interesting patterns. And from this compressed code predictions of the future follow (via some model; and pinpointing this model is essentially the problem of finding the hamiltonian).

Normal autoencodres is commong technology in digital soundprocessing, predictive encoders does not compress and reconstruct, but it compresses and and predicts with future stats in mind.

This would get us away from fictive "ensembles". Instead one predicts future sequence from a specific history. So no ensembles needed. This would make sense both for smaller "observers" and experimental human context. The difference is the memory and computational capacity the "autoencoder" has.

QM as it stands is formulates as if memory and processing is never limiting.

But "what if" the explanation to why nature entertains non-commutative encodings, lies precisely in that it is more efficient. Then we will not see it until we acknowledge the physical limitations of "observation".

This is why I think the observer concept is more central than ever.

So I'm curious to hear if you have put your idea in this context?
We perhaps parted company because you knew very well that I talk a big game about "signal analysis" but I have no detailed knowledge, a selectivity that I have deliberately chosen because otherwise I would likely fill my head with only signal analysis. The ideas you suggest above seem terrific to me —and very natural in the unified framework that I try to establish for classical and quantum physics— but I have no ability to develop them or even to help you develop them beyond what you would think of as platitudes.
I have entertained an idea similar to "nature entertains non-commutative encodings [precisely because that] is more efficient", and I think you've given us a nicely terse statement, but I would add a proviso that it isn't clear to me that any finite amount of experimental evidence can determine once and for all whether a single commutative encoding can encompass all of nature.
I think most closely relevant to that idea is this slide in the appendices of my Bhadrak talk,
1742128377737.png

The last four lines of that seems to me a more empiricist perspective than you suggested: noncommutativity is a useful tool that can compress *many* datasets in a way that gives us an effective way to describe how we should interpolate between the datasets we have to obtain predictions about a dataset we hope to collect in future (if we want to know whether a given new bridge design will fall down, we don't only ask how it's like one other bridge, we consider to what extent it's like as many previous bridges as have relevant data for).
We know this Generalized Probability Theory is effective because QM has refined its use of it, but it's a mathematical tool that classical physics can also use effectively.
I think the bottom line is that the whole of physics is ≫10⁶ researcher years, which no one person can reproduce. If other people can't see ways to make a new network of ideas become part of a progressive research program, such ideas as I've been trying to develop will die and good riddance. Towards that, I think what you've suggested above is a decent start for someone to make it into a compelling PhD thesis. A unification of classical and quantum frameworks gives us a freedom from worrying about whether any system is classical or quantum and focus on what I think are more interesting questions.

I hardly ever see a distinction made between (1) measuring a voltage on a signal line at GHz rates, say; and (2) measuring a voltage on a signal line at GHz rates and deciding whether the signal has suddenly transitioned in such a way that it is appropriate to say that at a particular time an 'event' happened. The recording of the time when such a decision was made is in modern experiments always delegated to a mixed hardware&software implementation, in a way that is both the same as and different from a person recording the time of an event in a 1920s lab notebook. In both cases, a classical algorithm lossily compresses the data from Gigabytes per second to kilobytes per second.
The very delicate decision about how to program the lossy compression of the data results in what I think is an important distinction between (1) and (2) that is perhaps precisely about the nature of the observer as a decisive agent, because for (2) we do not perform a measurement when we want, we wait for nature to perform the measurement, so to speak, but we or our computer has to decide when an event happened.
 
  • #24
SephQ said:
Yes, I did consider “observers” as to be any physical system that can cause interactions.

But to sum it up for what i’ve seen (which may or may not be wrong):
1. Without observers, the world can still exist just fine. Observers do not play a role in the development of the universe.
How can the universe "develop" without any interactions? It certainly had interactions all the time.
SephQ said:
2. QM simply describes the world under the circumstance that there is a observer.
Yes, QM is most useful when there are interactions to study.
 
  • #25
FactChecker said:
How can the universe "develop" without any interactions? It certainly had interactions all the time.
I don’t think your definition of “observer” is same as mine, but you do have a point.

Also I’m gonna open a new thread soon :D
Have fun studying QM!

(very) Best regards,
Seph :D
 
  • #26
Fra said:
even contemplating was possibly before the 4D manifold, like in string theory for example.
String theory doesn't say anything was "before" the 4D spacetime that we use to model the universe. It just says that that model is incomplete: a full model includes more dimensions. But those dimensions are still "with" the 4D spacetime we know. They're not something outside or "before" it.

Fra said:
I think it seems reasonable to think that at some point near the breakdown of current models, the "candidates" of material observers, should break down as well as what could possibly be stable?
Ordinary non-relativistic QM would not even be applicable under such conditions. You would be using quantum field theory. (String theory is a kind of quantum field theory.) The whole concept of "observers" as you're used to it in non-relativistic QM doesn't really exist in QFT.
 
  • #27
SephQ said:
QM simply describes the world under the circumstance that there is a observer.
This is not correct. Especially when you take quantum field theory into account.
 
  • #28
Peter Morgan said:
I have been developing it
Has this, or the material it's based on, been published in a peer-reviewed journal?
 
  • #29
PeterDonis said:
This is not correct. Especially when you take quantum field theory into account.
I think we have different definitions of “observers.” What I mean of an observer is a physical system that can conduct an “observation”, or rather an interaction that causes quantum to turn from uncertainty to a physical state. Hopefully this clears things up, and please elaborate so that i can understand better <3

After all, I’m new to QM and i could be very very wrong :p

Best regarding,
Seph
 
  • #30
SephQ said:
What I mean of an observer is a physical system that can conduct an “observation”, or rather an interaction that causes quantum to turn from uncertainty to a physical state.
There is no such thing. "Turn from uncertainty to a physical state" is a pop science description and is not valid as a description of what the actual physical model says. So your question is based on a false premise.
 
  • #31
I see… I think I’m gonna lock the thread here since that’s probably the case. An “observer” is kind of an undefined thing where it can vary from person to person, so I suppose I had a wrong understanding on what it is. Still, thanks a lot for explaining all of this to me!

Best regards,
Seph

(oh right how do i lock it i actually don’t know)
 
  • #32
SephQ said:
how do i lock it i actually don’t know
You don't. You ask a moderator, like me, to lock it. :wink:

I have now done so. Thanks to all who participated in the thread.
 
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