Has quantum mechanics proved that reality does not exist?

There have been headlines in the news claiming that physicists have shown reality doesn't exist. Is this true?

I suppose we need to define reality. Take the example of a pair of dice. When you throw the dice, you have no idea if you're going to get a 7, or a 2 (snake eyes), or something else. Does this mean the dice aren't real?

No, it just means it's difficult to predict a single outcome from a single roll of the dice. But if you roll them 1000 times, you will usually get a distribution reasonably close to what was mathematically predicted, presuming the dice aren't loaded. Quantum mechanics can work like this where you can't exactly predict a single outcome, but you can predict things statistically, such as where you can expect to find particles on a screen in the double slit experiment.

There is an unsolved problem in quantum mechanics called "The measurement problem". In the case of watching particles hit a screen in the double slit experiment, there doesn't seem to be a measurement problem because when the particle hits the screen, that's a measurement of the position. But one problem is this, what if you're not watching the screen, but you have to wait for someone who was watching the screen to tell you what the outcome was? Before they tell you, you don't know the outcome, so from your perspective you can't say a measurement has been made.

This idea is where some of the claims about "reality not existing" have come from, the idea that we haven't formally formulated exactly what constitutes a measurement and what doesn't. But intuitively, it makes sense that the "real" measurement takes place when the particle hits the screen. Waiting for someone to report to you what they saw on the screen seems a bit disconnected from the actual measurement, doesn't it?

Sabine Hossenfelder made a video about this and explains that physicists still have concerns about not being able to define exactly what constitutes a measurement, but she thinks that saying "therefore reality doesn't exist" is the wrong way to interpret the contradictions.

She sums it up as follows:

Has quantum mechanics proved that reality does not exist?

The alleged mystery of all those arguments and experiments disappears once you take into account that a measurement is an actual physical process. But since quantum mechanics does not require you to define just what this process is, you can make contradictory assumptions about it and then more contradictions follow from it. It’s like you have assumed that zero equals one, and then show that a lot of contradictions follow from it.

So to summarize, no one has proved that reality doesn’t exist and no experiment has confirmed this. What these headlines tell you instead is that physicists slowly come to see that quantum mechanics is internally inconsistent and must be replaced with a better theory, one that describes what physically happens in a measurement. And when they find that theory, that will be the breakthrough of the century.

I find Sabine Hossenfelder's argument persuasive, and it should be no surprise that we have a longstanding problem of not knowing how to interpret our theories of quantum mechanics (Copenhagen versus DeBroglie-Bohn versus Everett etc). We need to dig deeper to understand why her explanation is the correct one but it involves decoherence, which she mentions in the video that summary came from which you can watch if you want to dig deeper (or read the full transcript linked above):



So when I see threads like this one: Can a materialist provide scientific evidence that the material world has an objective existence?, I want to encourage people to watch SH's video or read her transcript for a deeper understanding of why the argument that "reality doesn't exist" falls apart under scrutiny.

Here are some other links if you want to dig deeper.

Solving the Measurement problem would hopefully lead to the improved theory of quantum mechanics that Dr. Hossenfelder spoke of.

In quantum mechanics, the measurement problem is the problem of how, or whether, wave function collapse occurs. The inability to observe such a collapse directly has given rise to different interpretations of quantum mechanics and poses a key set of questions that each interpretation must answer.

Wigner's Friend thought experiment has been involved in some of the claims about reality not existing, but Dr Hossenfelder explains how some "Wigner's friend" experiments use photons as so-called "observers" and I don't think Wigner had photons in mind when he talked about "observers". Dr Hossenfelder had this to say about using photons as "observers".

But of course an interaction with a single photon doesn’t constitute a measurement. We already know this experimentally. A measurement requires an apparatus big enough to cause decoherence. If you claim that a single photon is an observer who make a measurement, that’s not just a fanciful interpretation, that’s nonsense.

There's that word "decoherence" again, and I think understanding that is part of the key to solving these apparent contradictions, and understanding the basis of our "reality", however you want to define that.

During a transfer of momentum dp, the wave function collapses to a size similar to dx = hbar/dp.

I proposed the above physical definition in a publication decades ago. That proposition was discussed on your now-closed AMA thread, and I don't believe it was ever successfully refuted. The only thing that is required to accept the above definition is that relativity be set aside in favor of absolute theory.

It is the combination of relativity and quantum mechanics that has a problem with realism, not quantum mechanics alone.

On a personal note, I've been insanely busy since January as my first job has required a massive overtime commitment and I have two other jobs that also have required a lot of time. This situation should resolve in a month or so, and I plan on writing the promised thread on an alternative to GRT and also respond to your months-old thread concerning the state of fusion research.

Great to see you are still here, and that ATS is still up - I hope we can have good discussions on these matters.

a reply to: Arbitrageur

Wouldn't proving that reality doesn't exist become a reality in itself that surely does exist?

The measurement problem of superposition could be removed by superimposition.

In the case of 2 entangled particles of +1 and -1 spin. How could 2 Alice's possibly agree with each other? The 2 particles are a complete form when entangled. Of course their measurements would conflict. But together, would describe the complete measurement of the entangled pair.

Spin is an intrinsic property of particles. Spin is a property of rotation. Therefore, how could spin or rotation exist if it were not for a fixed set of coordinates by which to measure the changes other than by superimposition of a fixed and rotational set of coordinates?

a reply to: Arbitrageur

we could be getting sucked down a black hole and time is so dilated that the rest of the universe is dying and because of time dilation and the fact the last things in the universe or at least one of them will be super massive black holes


we could exist in the event horizon as some sort of 3d hologram


personally I believe time is one instant past, present and future all happening at once and we are on the 'wave' of "now" when the rest of existence is blinking out.


would explain how things seem to all be moving away from us aka red shifted as we fall into the abyss.

if time and space are linked and they more than likely are, if time is just a perception of 3D existence, the way we move across space is with time so we cant perceive time as it really is.

Just practical advice.

You can argue for an eternity about the existence of a large oak tree, even proving in theory that said tree has no real existence, until you try and run your car into the tree at 80 miles per hour to see how real it is.

As unreal as our senses can make reality seem, they have evolved to help us effectively navigate said reality. I'll stick to what I can sense and not worry about how real things actually are in some abstract mathematical theories involving observations made during scientific experiments.

a reply to: Arbitrageur

I'll have to wait for the artists conception, impression, interpretation, or rendition of Centaurus A imaging in a few weeks.
Slit lamp isn't really a paradox for me, but I've always thought of Centaurus A as an unfathomable non-intuitive superposition.
Of course some of the worlds best cryptographers believe the traffic recordings from the SIGSALY would be uncrackable forever.

eventhorizontelescope.org...

I find rolling dice 1,000 times as an experiment intriguing. I would propose doing it two different ways; 1,000 people guess the outcome, and then roll 1,000 pairs of dice. And also have one person roll a single pair of dice 1,000 times. My hypothesis would be 1,000 people doing it once would be close to the mathematical prediction. However, I think if you had one person roll the single pair of dice 1,000 times, over time it would depart from the mathematical prediction because the person would consciously or subconsciously begin to see patterns in the results of the physical dice which are imperfectly weighted, being rolled in an imperfect environment, and rolled on an imperfect surface.

Now that does not prove definitively that reality exists. Only that we are able to interact with something that exists in relation to our consciousness.

originally posted by: Arbitrageur
There have been headlines in the news claiming that physicists have shown reality doesn't exist. Is this true?

I suppose we need to define reality. Take the example of a pair of dice. When you throw the dice, you have no idea if you're going to get a 7, or a 2 (snake eyes), or something else. Does this mean the dice aren't real?

No, it just means it's difficult to predict a single outcome from a single roll of the dice. But if you roll them 1000 times, you will usually get a distribution reasonably close to what was mathematically predicted, presuming the dice aren't loaded. Quantum mechanics can work like this where you can't exactly predict a single outcome, but you can predict things statistically, such as where you can expect to find particles on a screen in the double slit experiment.

a reply to: Arbitrageur

Always loved the way Dr. Quantum explains the double slit experiment...

Just because reality is "fuzzy" -- i.e., a particle can seemingly be everywhere at once until it is measured -- doesn't make it any less real.

The true nature of reality is what it is, fuzzy or not, but it is still the true nature of reality. If it's the only reality we have, then it is real.

a reply to: Arbitrageur

S+F for the excellent presentation of a topic that confused SO MANY people - including what I call "celebrity physicists" that make the CNN headlines but just have no idea what they are talking about.

originally posted by: delbertlarson
During a transfer of momentum dp, the wave function collapses to a size similar to dx = hbar/dp.

I proposed the above physical definition in a publication decades ago. That proposition was discussed on your now-closed AMA thread, and I don't believe it was ever successfully refuted.

I can't refute it either, but remember that physicists don't even agree on whether the wave function actually collapses or not, ever. That may be especially surprising to some people who studied undergraduate physics where the same physicists teach their students about wave function collapse using the Copenhagen interpretation, when in fact they may not actually subscribe to the Copenhagen interpretation. Some prefer the Everett interpretation where the wave function doesn't collapse, or some other interpretation. Those physicists who disagree with each other about how to interpret quantum mechanics mostly agree that they can't refute others who think differently, because so far nobody has designed a convincing experiment to distinguish which interpretation (if any) is correct.

I'd be interested to hear more about the state of fusion research so good luck on freeing up enough time to write about that!

originally posted by: noscopebacon
a reply to: Arbitrageur

we could be getting sucked down a black hole and time is so dilated that the rest of the universe is dying and because of time dilation and the fact the last things in the universe or at least one of them will be super massive black holes


we could exist in the event horizon as some sort of 3d hologram


personally I believe time is one instant past, present and future all happening at once and we are on the 'wave' of "now" when the rest of existence is blinking out.


would explain how things seem to all be moving away from us aka red shifted as we fall into the abyss.

if time and space are linked and they more than likely are, if time is just a perception of 3D existence, the way we move across space is with time so we cant perceive time as it really is.

Time certainly has a lot of mysteries and you could make a whole separate thread or threads about those. Time dilation is generally considered with respect to general relativity, the other major theory besides quantum mechanics, but relativity isn't the topic of this thread, it's about quantum mechanics and whether experiments have shown that reality exists or not. Some of the ideas you discussed such as the hologram are discussed in the ATS thread I linked to in the OP, which has been necro-bumped recently if you want to continue the hologram discussion there.

originally posted by: ByteChanger
a reply to: Arbitrageur

Always loved the way Dr. Quantum explains the double slit experiment...

Yes and you have lots of company, but unfortunately the movie that clip came from has been widely criticized because it mixes together quantum science and quantum nonsense, and unfortunately the average layperson can't tell where one ends and the other begins. Even in that clip, part is quantum science and quantum nonsense. An aspiring physicist posted people's reactions to that clip in this video:

People See the Double-slit Experiment for the First Time


This is in her comments with a link to the follow-up video, explaining what is wrong with that Dr. Quantum video:

"I have made a follow-up video to clarify some flaws in this explainer"

Here's the follow-up video. I suggest to watch at least the follow-up video, to get an understanding of what is wrong with the Dr. Quantum video:

The Problem with Dr. Quantum's Double-slit Experiment



For those who don't watch the video, the problem is this. Dr. Quantum talks about behavior of the particles changing when we try to observe which slit they go through almost as if they know they are being observed, which implies some kind of consciousness of the particles. The paper explains why consciousness need not be involved and links to a scientific paper explaining this:

Quantum mechanics needs no consciousness

If you want a non-quantum example of the Observer Effect, you can think of measuring tire pressure. When you apply the tire pressure gage, a little bit of air can leak out, so the act of measuring the tire pressure can actually change the tire pressure. Likewise in the double-slit experiment, the act of measuring the particles can affect the particles...it's just kind of silly to imply that involves any kind of consciousness by the particles. We could also say the tire changes its pressure when we measure it almost like it knows it's being observed...implying some kind of consciousness of the tire when it doesn't involve any consciousness, it's just a little pressurized gas escaping from the tire because of the way the gage works.

The rest of that "what the bleep" movie gets even worse in terms of implying more crazy stuff that science doesn't really imply, so it's really a source that's best avoided if one wants to keep fiction separate from fact.

originally posted by: MichiganSwampBuck
Just practical advice.

You can argue for an eternity about the existence of a large oak tree, even proving in theory that said tree has no real existence, until you try and run your car into the tree at 80 miles per hour to see how real it is.

As unreal as our senses can make reality seem, they have evolved to help us effectively navigate said reality. I'll stick to what I can sense and not worry about how real things actually are in some abstract mathematical theories involving observations made during scientific experiments.

I've seen philosophical arguments about the tree not existing until it's observed, but those are silly because air molecules are constantly bouncing off the tree, so it's constantly being observed by those, which is tied up in the concept of decoherence. So yeah, trees are there even if they aren't observed by you because they are still interacting with the environment like interactions with air molecules. Subatomic particles can be a bit more ephemeral, especially when the experiment is cooled to near absolute zero to prevent decoherence.

a reply to: Caled
Let me know the results of your experiment and whether your prediction turns out to be accurate or not. Remember I did specify that it would be "non-loaded" dice which would best fit mathematical predictions, but you seem to be implying some kind of "loading" of the dice in your comment.

originally posted by: Box of Rain
Just because reality is "fuzzy" -- i.e., a particle can seemingly be everywhere at once until it is measured -- doesn't make it any less real.

The true nature of reality is what it is, fuzzy or not, but it is still the true nature of reality. If it's the only reality we have, then it is real.

I think you can make that argument successfully but I prefer to emphasize the decoherence aspect of why reality seems real to us...we don't normally perceive individual subatomic particles with our five senses, but we can definitely perceive the tree discussed above in a very real state because of the decoherence achieved though interacting with its environment.

a reply to: swanne
Thank you kindly.

We could also say the tire changes its pressure when we measure it almost like it knows it's being observed...implying some kind of consciousness of the tire when it doesn't involve any consciousness, it's just a little pressurized gas escaping from the tire because of the way the gage works.

Could you go into a little more detail?
I see what you are implying but not how the two equate.
When we check the air pressure in a tire we are actually changing the pressure in the tire, whether we observe the measuring device (gauge) or not.
So, even if you don't look at the gauge, just the simple act of applying the measuring device changes the tire pressure.
It is my understanding that, in the case of the DSE, the results only change when the measurements are being observed, not by the measurement process alone.

a reply to: Arbitrageur

If reality does not exist, this this non reality really sucks...

If I created it, then I really suck.

If god created it, then he really sucks.

Therefore, reality exists, and it's just the confabulation of randomness alluding to the fact it might not exist. Which means it does.

originally posted by: MichiganSwampBuck
Just practical advice.

You can argue for an eternity about the existence of a large oak tree, even proving in theory that said tree has no real existence, until you try and run your car into the tree at 80 miles per hour to see how real it is.

As unreal as our senses can make reality seem, they have evolved to help us effectively navigate said reality. I'll stick to what I can sense and not worry about how real things actually are in some abstract mathematical theories involving observations made during scientific experiments.

☝️This is the best answer. Trying to deconstruct inconvenient physics into being a trick of the mind only means existence is a trick of the mind and there is no trajectory or destination which defeats the purpose of abstraction and redefinition. Either you figure out how to love what you can't reconfigure and erase, or there's nothing at all and nowhere to go except where you already were and can never be. That's it.

I think the point is that reality doesn't exist in the way that we normally thought. Consciousness, and not matter, Is the fundamental aspect of reality.

originally posted by: cooperton
I think the point is that reality doesn't exist in the way that we normally thought. Consciousness, and not matter, Is the fundamental aspect of reality.

Let's try a thought experiment, shall we. Consciousness is unnatural and a cumbersome burden on organic life, bestowed at best by happenstance chemistry and at worst by a bored sadistic agency who wanted their toys to kick and scream a tiny bit more. There's no practical advantage except to exploit what you have awakened for selfish gain. Your rebuttal would be...?

originally posted by: TzarChasm

Consciousness is unnatural and a cumbersome burden on organic life, bestowed at best by happenstance chemistry and at worst by a bored sadistic agency who wanted their toys to kick and scream a tiny bit more. There's no practical advantage except to exploit what you have awakened for selfish gain.

No concepts would exist whatsoever without consciousness to measure them. It is an assumption that there was ever a physical world without a conscious agent. As I said in the post above, this is the opposite of what we're taught, but it is a prime aspect of quantum physics:

"I regard consciousness as fundamental. I regard matter as derivative from consciousness. We cannot get behind consciousness. Everything that we talk about, everything that we regard as existing, postulates consciousness.”

-Max Planck