One other thing about the math in QM.

The experiments are primary, not the math. Math is used to model and predict experimental results. Schrodinger's equation exists because of the double slit experiment and others like it.

So a natural question to ask is whether the math fully takes everything relevant into account. In this interpretation, the unknown quantum state of the measuring device is a potential source of something important not being taking into account.

The problem is it doesn't work. Take out the measuring device and one is talking about a different interaction in the world. It is no longer a state we are measuring with a device. A measurement without a measuring device is nothing more than an incohrent fantasy. — TheWillowOfDarkness

No, it's about accounting for the measuring device, not removing it.

The argument:

The measuring device is the source of uncertainty in these experiments. You don't agree, fine. You don't want to watch the video or research his position, fine. You don't wish to counter the argument, fine.

But calling it not an argument? That's bollocks. In fact, I would say your response is irrational.

I don't know that his or the HMI interpretation is right. It could be entirely wrong. I just wanted to hear legitimate feedback. My suspicion is that taking into account the measuring device won't make the uncertainty of the particle disappear. Too many experiments suggesting otherwise. But it's worth considering, just in case our understanding of QM resides on not taking something into account.

Yes, I have no idea what he is saying, let alone what he meant to say. I am suspicious of all prose presentations of QM. QM is mathematics and needs to be presented as such. — andrewk

But the interpretations stem from the measurement problem, which is not accounted for by the mathematics. That's one thing.

The second thing is to recall history when Newton proposed the law of gravity, and his critics wanted to know how an invisible force acted at a distance on objects. This troubled Newton as well, but he didn't have a good answer at the time.

Now imagine Newton and allies telling everyone to shut up and calculate, the math was all that mattered. And maybe they did back then. But we know now that Newton's formulation of gravity was incomplete. And how did Einstein come up with a better formulation?

It certainly wasn't from math, it was from asking deep questions about gravity and related phenomena, and then doing (or finding) the required math to make it work for GR.

'm not going to criticise Prof Binney though because I haven't watched his video, just as I don't read designs for perpetual motion machines or proofs that one can trisect an angle. I don't need to because I know it either doesn't say what people think it does, or it is wrong. — andrewk

That's entirely dismissive and not a good counter argument. You need to be able to show how Binney and advocates of Hidden Measurement are wrong about the measuring device introducing the uncertainty.

The ket associated with a system evolves over time according to a known differential equation, called Schrodinger's Equation. — andrewk

Problem being that when a measurement takes place, Schrodinger's equation fails to predict the outcome, unless of course MWI is endorsed.

I expect he just expressed himself poorly - not an unusual occurrence for scientists trying to communicate to a non-scientific audience. The Uncertainty Relation is derived directly from the four postulates of quantum mechanics, with no additional assumptions*. It doesn't get more fundamental than that. — andrewk

I don't think that was the case. He repeated himself a lot, and was rather adamant. He doesn't except certain postulates as being anything more than useful modelling tools. Also, becuase the other speaker conceded that MWI would be unnecessary if the measuring apparatus is the culprit of the wave function probability distribution.

Binney did state several times that the measuring device has a precise quantum state that is mostly classical, we just lack the means to measure it accurately.

If you want, you can listen to Binney's portion of the talk. It's a bit long.

https://youtu.be/NKPI_wurNlo?t=37m21s

However, I wonder whether what your physicist was actually referring to was the notion of Decoherence, which is a fairly intuitive (some might say 'pseudo-classical, but one has to be careful using vague terms like that) way of explaining what happens in a measurement of a quantum system. The reason I think he might be referring to that is the reference to the interaction between the state of the observed system and the state of the measuring apparatus, which is what Decoherence addresses. — andrewk

I don't know, sounded to me like he was denying that the Uncertainty Principle was fundamental instead of a useful approximation based on epistemic limitations.

As such, the title is misleading. It is a hidden variables approach, just not of the particle, and its non-classical. The way Binney stating things, though, was that the measuring device has exact properties at any specific time, we just can't measure all of them. But the HMI wiki entry states there are quantum fluctuations of the device when it makes a measurement.

From my reading, Bohr met every one of Einstein's challenges along these lines (as detailed in Manjit Kumar's book Quantum).The final nail in the coffin was Aspect experiments which falsified the EPR conjecture. — Wayfarer

Yeah, but I don't think it falsifies HMI (hidden measurement interpretation, which looks basically like what Binney was promoting). That's because the hidden variables are not in the particle, they are in the measuring device (our lack of knowledge of its exact state, or the fluctuations of the device when detecting the particle). Looks like HMI is not entirely classical in that the quantum state of the device does fluctuate, but maybe that's consistent with Binney stating at one point that particles are just excitations in the quantum field.

Binney does reiterate during his portion of the talk how the measurement device is always left out of the modelling of the experimental results, because it's too complex to model, but arguments over the interpretation of QM always forget that.

It sounds a bit like the hidden measurement interpretation (https://en.wikipedia.org/wiki/Hidden-measurements_interpretation) — Gooseone

Yeah, that's pretty close to what Binney was arguing for. I don't recall that he mentioned any history of the development of hidden measurement, which often happens with the other interpretations. Looks like the wiki entry goes a bit farther with it than I recall Binney mentioning, but I've only listened to the talk once.

Binney's view of the wavefunction is that it's a really useful and powerful tool, given our limited knowledge, but it has unreal properties, such as superposition. He thought the notion of a superposed cat to be absurd, like Schrodinger did. Basically, Binney thinks all the other interpretations of QM go wrong because they took the wave equation to be something more than a useful tool.

It's not metaphysical in the slightest, it's the real physical situation. And, the other worlds are required to explain what we see in this world in terms of interactions with them - i.e. it is a testable prediction. — tom

Anyway, I didn't make this thread to debate MWI, or any other standard interpretation. I wanted to know what people thought about Binney's interpretation.

I'll restate it briefly. There wavefunction is not real. Rather, our uncertainty about the exact quantum state (which is classical in Binney's interpretation) is translated to the particle or particles in these experiments. If we could take into account the exact state of the measuring device, then the uncertainty of the particle's property in question would dissipate, and thus there would be no need for the wavefunction.

I heard about this watching a youtube video of a conference in which Binney and an MWI proponent got to talk for a while and then field questions. The MWI proponent conceded to Binney that MWI would be totally unnecessary if the measuring device is the culprit, but doubted that having more exact knowledge of its quantum state would make the uncertainty disappear.

It's not metaphysical in the slightest, it's the real physical situation. — tom

LOL! Only if you take Schrodinger's equation to be modelling a real state of affairs, and disregard all other interpretations, or the possibility that QM will be superseded by a better theory at some point.

I'm not saying that MWI is untrue, I'm just pointing out that it's one interpretation based on taking the wavefunction literally. Of course, I have no idea what's ontologically the case.

And, the other worlds are required to explain what we see in this world in terms of interactions with them - i.e. it is a testable prediction. — tom

That's not testable unless it makes predictions the other interpretations don't. And we don't have anyway of going to or viewing those other worlds. It falls out of the math, nothing more.

Hell, even penguins are known to commit suicide. — darthbarracuda

Penguin suicide? How do they manage that?

So I focus more on non-human animal welfare, those residents of the Earth that are continually neglected and forgotten about. — darthbarracuda

The sorry state of chickens?

So my contention is just that people don't have the skills to improve the world in that way - they're too stupid. — The Great Whatever

I thought the contention was more fundamental than that. Being born an animal subjects one to a life of suffering in one form or another. Some more extreme than others, but even the richest, most comfortably lived life still has to contend with boredom, frustration, relationship difficulties, possibly addiction, maybe unhappiness or mental illness, etc.

That problem can't really be solved. We can determine what the optimal environment is for the human animal, and aim for that, but it won't get rid of existential concerns and other problems everyone faces to some degree.

All that being said, there is certainly a substantial difference between feeling depressed and bummed out about life, and feeling decently well, and engaged. Or between lots of pain, and minimal daily discomforts. Or I would imagine, between having plenty of food, and starving.

Sure, what I mean is that it's a pretty big metaphysical bullet to bite.

What is the point of active pessimism? If life is such that one should be pessimistic about it, why bother with some virtuous ascetic attempt? Why not just enjoy what you can, and avoid as much suffering as reasonably possible, without being a total asshole? You know, what most people do.

Do you get points after you dife for having lived an actively pessimistic life? Do you get to pat yourself on the back for being virtuous and feel pride in your embracement of life's misery? Why would that matter? Or does it just make one feel good?

Me, I'd rather drink a beer and pass the time doing something half-way enjoyable or interesting.

The problem with indeterminism as currently defined (exact sets of causes can have variable effects) is incoherent to me. It seems to violate basic causation, a fundamental concept for our comprehension of the world (ala Kant). So, my inclination is to accept any expert's rejection of QM indeterminism just because all else is incomprehensible. — Hanover

There is an entirely different possibility, ala Kant. The real world is very different from our ability to conceive it, and the rubber meets the road at QM, where we find out the truth of our limitations.

What's the QM problem? Why is it a problem that the result is indeterministic (better said probabilistic)? — Agustino

There's a better way to state the problem. The Schrodinger equation doesn't show any sort of "collapse" to a single outcome, which is based on a probability. No quantum system is like that. But we get that when we decide to measure for something.

So why should a measurement, which is done by a physical device that is presumably made up of the same sort of quantum particles, result in a zeroing out of all other possibilities in the wave distribution to one single actuality?

That's the motivation for Many Worlds, btw. It removes the collapse issue, but at a cost of postulating a vast number of branching worlds that we can't interact with. But if you're willing to roll with that, it works.

Or you could do what Binney has done, and question the assumption that the Schrodinger Equation must be modelling something real. His position is that it's a useful tool, but it has properties which are fantastical and unreal. And he avoids ducking the question that instrumentalists do, or proposing some form of idealism, which Bohr may have preferred. Instead, he favors one, classically real world.

The issue is that basically claims non-locality. If our problem is an inability to locate particles, then our local space is defined by something else, by things which cannot be pinpointed in our immediate vicinity.

It also effectively claims a hidden variable: if only we knew this hidden state we can never know about, then we could recognise how an electron was pre-determined to hit the screen. — TheWillowOfDarkness

No, because he's basically rejecting point particles in favor of a quantum fields. The fields have wave-like properties. When they interact with something like a detector, then the exact quantum state of that detector determines the exact measurement. A particle is just a certain kind of excitation of the quantum field.

As such, there is no need for any hidden variables or non-locality.

But then how do you account for all the things that General Relativity does? Gravitational lensing of stars and Galaxies, Mercury's orbit, neutron stars and black holes, gravity waves, time dilation, the Big Bang and inflation, red shifting of distant galaxies, etc?

And there's the fact that acceleration gives you the same force as gravity, which is what led Einstein to GR.

Gravity? You mean space-time curvature I hope, and no, space-time is real. — tom

Gravitons, I would presume. And space has quantum foam, where virtual particles pop in and out of existence, creating energy that supplies most of the mass for particles.

Your other questions are meaningless. Shut up and calculate instead. If you don't like being told what to do, tough! Probabilities are normative. — tom

Yeah, but part of science is asking why phenomena appears the way it does. What's going on behind the scenes? Imagine if Newton and Einstein had stopped at an equation for gravity and told everyone to shut up about the reality behind the equation.

The related concern is why should Schrodinger's equation work at all? Just saying that it fits experimental data is no answer at all. I was watching a video last night where Brian Green brought in four people to discuss the various interpretations of QM. One of them summed up the measurement problem as asking the question: what sort of world do we live in to get the sort of results that the double slit experiment gives us?

More interestingly, a universal computer inside a black hole could simulate the black hole. — tom

So a universal computer could compute the result of itself being sucked into a black hole and having contact with the interior (singularity or whatever lies there).

Although, this seems unfair. I'm guessing the idea of simulating precludes the thing doing the simulating, otherwise we have regress and self-referential issues. I might as well ask if the computer can simulate itself itself being introduced to a really strong magnet, or whatever would disrupt a QC.

Perhaps a more fair question would be could a QC compute a black hole used as a computer? I ask, because there are some articles out there about the possibility of black hole computers:

https://aeon.co/essays/is-the-black-hole-at-our-galaxy-s-centre-a-quantum-computer

Surprisingly, according to the laws of physics, simulating the entire visible universe is indeed possible using a universal computer, from within the universe. — tom

Back to this. Let's say all of physics is computable with a few hundred qubits, including black holes and Microsoft Office for all sentient beings insid the visible universe. Do we know what the algorithm for consciousnes is, such that our simulated Office users experience the Joys of making yet another thrilling Powerpoint presentation?

It depends on the size of the black hole. If the black hole is smaller than the visible universe, then yes. More interestingly, a universal computer inside a black hole could simulate the black hole. — tom

What does the algorithm for computing a black hole look like? Do we know that a quantum computer can operate as a turing machine, and do we know that black holes are computable?

Let's say the answer to the first is yes, do we know that a simulation running on qubits is more efficient than a classical computer? I know that quantum computers can perform some algorithms much faster, but I'm pretty sure there are plenty of programs that would not benefit. Like say, running Microsoft Office on a quantum computer.

So let's say you have hundreds of qubits available. Does that mean you could run Office 365 as a service for every human being on the planet?

The visible universe is thought to contain about 10123 bits of information. A rudimentary quantum computer containing only a few hundred qubits vastly outstrips that! — tom

Do you think that a few hundred qubits could completely simulate a black hole? And by that, I mean the object itself, not just the effect on things outside the event horizon.

How would the computer compute the future of the universe without being the entire universe? And if the entire universe isn't computing ahead such that we know the future, then you can't have a computer inside the universe doing so.

At any rate, if someone assigns no meaning to that sentence, then "This sentence is meaningless" is simply true. — Terrapin Station

If the sentence is meaningless, then it can't be true.

It's not true. The sentence isn't truth-apt.

It really is a straightforward proof by contradiction. If it being either true or false leads to a contradiction then it must be neither true nor false. — Michael

That seems like cheating. Now you can just remove any paradoxical statement by saying it's neither true or false. Let's try this as a result:

"This statement is neither true or false."

Does that lack a truth value? I say no, it has a truth value if what you stated is true. And then you're right back at the liar paradox.

Surely, if it were that easy, the liar paradox wouldn't have remained a puzzle to philosophers for 2300 years!

Any of them. — Michael

The third one is the "strengthened" liar paradox. Consider:

"This sentence does not express a true proposition."

If it's true, then you're back at the same contradiction.

The Liar sentence is not of the form 'L and not-L', and attempts to derive a sentence of that form from the Liar sentence make untenable assumptions. — andrewk

Which form of the liar statement?

I am lying.

This sentence is false.

This sentence is not true.

The next sentence is true.
The previous sentence is false.

With math and logic it's a matter of using the axioms and the rules of inference to determine what follows from what.

There's nothing like either of that for liar-like statements. — Michael

I don't know how you can say that. The contradiction in the liar statement stems from following the rules of logic. If not, then why is it considered an issue?

I've never really understood the problem of the liar paradox, even after reading a little about it. Think of checking for truth like running a program, and a program can loop infinitely without output. Same with self-referential paradoxes. — The Great Whatever

From finally getting curious enough to read up a bit on it, seems the motivation is to be able to define a theory of truth free of contradiction. Wittgenstein was of a different opinion. He thought it better to ignore the liar paradox instead of trying to figure out a way to resolve it, which in his view, might have worse consequences. I found that interesting.

Star Trek version:

KIRK: "Everything Harry tells you is a lie. Remember that! Everything Harry tells you is a lie!"

HARRY: "Now listen to this carefully, Norman: I AM LYING!"

NORMAN: "You say you are lying, but if everything you say is a lie then you are telling the truth, but you cannot tell the truth because everything you say is a lie, but... you lie, you tell the truth, but you cannot for you l... Illogical! Illogical! Please explain! You are Human! Only Humans can explain their behavior! Please explain!"

However you are still using binary logic in your clever example — TheMadFool

Here's an even better one that dates back to ancient times:

A crocodile takes a child but promise the parent he will return the child if the parent guesses what the crocodile will do. The parent responds that the crocodile will not give the child back.

What does the crocodile do in response? How would the crocodile get around this using an alternate form of logic?

This one is grounded, btw (other than the fact that crocodiles don't talk, but you can substitute a human kidnapper.)

There must be some evaluable fact about the world for the statement(s) to be "grounded", and so have a truth-value, but there isn't such a thing for the above. — Michael

Math and logic aren't grounded by the world. Also, there's fictional truths, such as Harry Potter performs magic.

If we refrain from any or both the paradox disappears. — TheMadFool

Well, here's a clever way to remove the self reference and still end up with the liar's paradox:

Socrates: "What Plato is saying is false"
Plato: "What Socrates is saying is true"

Post the representation, with details of the formal language being used, and we can discuss it. — andrewk

You requested that of MindForge, but since he hasn't gotten back to you yet, what do you think of the argument that SEP presents?

L = "This sentence is false" or "I am lying"
Q = "1 + 1 = 3" or any other false sentence

1. L and not-L from the Liar Paradox
2. L from 1
3. L or Q from 2 using the Law of Addition
4. not-L from 1
5. Q from 3 and 4