All universal computers are equivalent. What you need to argue is that a billion Chinese human computers, cranking out an algorithm, constitutes a computationally universal system which is realisable. — tom

Humans were computers before electronic computers existed. Is there a reason why enough humans given enough time can't compute any algorithm? How is that different from a turing machine with infinite tape?

Why not just program qualia on your laptop? — tom

Does anyone have any idea what sort of algorithm that would be? The point is to ask what it is about algorithms which could lead to experience.

You can take this as a criticism either against the computational theory of mind, or a criticism against universal computation (the substrate doesn't matter).

The OP question is, of course, a variant of the Chinese Room problem. — SophistiCat

It is except the focus is own conscious experience and not understanding. Arguably, a fair amount of progress has been made in computer understanding with machine translation, image recognition, search algorithms, etc. But no progress whatsoever, far as anyone can tell, has been made on experience.

Also, I'm delighted that you used pencil and paper, which I think is still the greatest technological innovation that our species has accomplished. — andrewk

Interesting. Why that one in your opinion over fire, clothing, or the printing press?

You can conjecture that decisions about the existence of intentional states and/or experiences is undecidable from current understandings in logic, sure.
It is probably more interesting than the physicalist position, sure.
But it certainly isn't logically necessary to speculate thus, at least not at this point. — m-theory

The same sort of thing could be said of external objects. An idealist could turn your argument on it's head and claim that material objects are undecidable for the physicalist.

If they are not decidable that poses problems for physicalism sure, it would mean that we cannot logically determine if we experience intentional states. — m-theory

I disagree that this something to be logically determined. My experiences would be the premises one starts with to make a logical argument. It's not something to be argued for. There is no line of reasoning I follow to logically determine that I see red. I just see red and am aware of it. That's where logical argument can begin, but not before then.

I don't need to determine that I have experiences. I have experiences, period. What do those experiences amount to (or what is their origin and nature)? That's something which can possibly be determined by logical argument, but not that I have them.

Now whether you have experiences which I don't have (as an extension of my experiences) is something which can and has been argued ad nauseam. But notice that the solipsist need not and cannot make an argument for their own experiences. They just are. It's brute.

All logical argument has to start somewhere.

Note that if mental phenomena and intentional states are undecidable then there is no method for concluding that those phenomena or states exist. — m-theory

You mean there is no objective method. Subjectively, I know that mental phenomena exist, because I experience it. That's how I can know with certainty that nobody else can be a solipsist, to the extent one takes solipsism seriously.

That is to say if you can be sure that you have mental phenomena there must be some effective mechanical procedure for arriving at that conclusion without error. — m-theory

You mean to be sure other people have mental content? Because again, I experience my thoughts, my perspective, my dreams, etc. Whatever mental content are, I have them, and I cannot doubt that I have these experiences, however one wishes to categorize them.

However no such breakthrough has been discovered so, philosophically, physicalist proceed with what we can know based on current methods. — m-theory

You mean what can be objectively known. Here is a potential problem for physicalism. It beings with objectivity, which means factoring out our individual subjective experiences. This works great for science. But it has the one big problem of turning around and explaining subjectivity, because at the start, subjectivity was removed.

In Lockean terms, you get rind of color, sounds, smells, etc to explain the world in terms of number, shape, extension, etc. That's great until you need to account for our having colors, smells, etc.

How does one derive smell from number? Is there a mathematical equation for experience? Do you now what sort of algorithm would enable a machine to experience the sweet smell of rose?

I think intentionality can be exhibited by mindless objects: robots, computer programs, animals. This in a way solves the problem of intentionality at a stroke. The big problem remains however - that of the quale of intentionality. — tom

Why group animals with robots and computer programs? Animals have nervous systems, and they have their own goals independent of us (often enough at odds with us). Computer programs and robots just do what we design or program them to do. As such, attributing intentionality to them could just be a case of anthropomorphism. Seeing intentionality in things that lack it because they have a behavior or look familiar to us. It's like seeing shapes in clouds or thinking the volcano god is angry.

For those who like the pilot wave theories: — Agustino

Actually, that video was pretty amazing! Maybe there really is something to pilot waves. I didn't know there was a classical system that produced similar results for the double slit experiment. And you can see it happening! Definitely helps visualize de Broglie's interpretation.

I guess the bouncing silicon oil drops creating the standing waves is a classical pilot wave system.

Yes we do — tom

Feynman said that nobody understands, assuming that wasn't taken out of context, but I always understood him to be saying that nobody knows why the double slit and other experiments give the results they do. How many nuances to the various interpretations are there, btw?

For systems of more than one particle, QM takes place explicitly in Hilbert space - not in the space-time. — tom

What is Hilbert space, and what makes it any more real than probability waves? And I don't mean what is the math, I mean what does the math represent?

I am sympathetic to everything you report him as saying there, and it's a widely held interpretation. — andrewk

I didn't explain what I heard well. It was only after several pages of replies that I figured out how to express it clearly.

That is why, I think, it is 'rate independent' - the 'wave pattern' really is embedded in the fabric of reality itself, it is of a different order to the physical. That is why the 'nature of the wave function' is the metaphysical question par excellence. — Wayfarer

This is where I get confused about the Copenhagen interpretation. Is it anti-realist, or is it saying that reality is this non-classical stuff of possibilities that behave like a wave? That seems to be two different interpretations.

The first one leaves questions unanswered. It's the sort of thing Landru of the old forum would have been happy to endorse. Our experiences have a structure. We don't know why, but realism just presents a regress, etc. In terms of the double slit experiment, we don't know why it results in an interference pattern when there isn't a detector on one of the slits. That's just what happens, and physicists developed the math to describe/predict it, because science is merely concerned with prediction (on Landru's account of it).

While the second one, that the world is actually made of probability waves until a measurement (or decoherence) takes place, is puzzling, weird, and almost mystical. The second one is making an ontological claim.

Einstein asked the rhetorical question 'does the moon still exist when nobody is looking at it?' — Wayfarer

It's gravity certainly does. The unobserved particles have properties that are important to atomic structure and fields of force. It's similar to noting that the floor keeps holding you up even when you don't notice it. Somehow the stuff of everyday life is held together despite not observing all the particles making it up.

One of Bohr's quotes is 'that there is no particle prior to the act of measurement'; which is why Einstein asked the rhetorical question 'does the moon still exist when nobody is looking at it?' — Wayfarer

Let's say Bohr was right. Why the interference pattern, then? Why not some other probability distribution? It's highly suggestive that something is interfering. After all, that's what observable waves do.

And science has a track record of positing what are initially unobservables, and then coming up with instruments to make those observations. At one time, atoms were just theoretical posits. Anti-realists could have (and maybe did) argue that they were useful fictions for making sense of experiments at the time. But now we can observe them, so obviously they are more than useful fictions.

o it would appear that the people involved are debating interpretations and not challenging the postulates of QM, or deductions therefrom like the Heisenberg Uncertainty Relation, which would have been a worry. — andrewk

Yes and no. I'm pretty sure Binney challenged taking the postulates of QM literally (realistically), when interpreting the results. He said they were very useful tools, but the Schrodinger Equation, for example, has unreal properties (such as leading to a superposition of states). He also mentioned the Heisenberg Uncertainty Relation, and I'm pretty sure his interpretation is at odds with taking that realistically, since he thinks probability is epistemic, and not fundamental. Thus, a measuring device has an exact quantum state (state that all the particles and molecules are in), and not a wavefunction.

Just to pick up one of the possible meanings, if 'uncertainty' refers to the probabilistic nature of the value obtained from the measurement, as assessed prior to the measurement, and based only on information about the observed system and not the measurement apparatus, then that agrees with the Decoherence theory, which is widely accepted. If that's what was meant then the prof is not saying anything controversial, or new, at all — andrewk

No, that's not what he was arguing for. Binney stated several times that the probabilistic nature of the value obtained was due to our epistemic uncertainty about the exact quantum state of the measuring device, and not anything fundamental about the state of the particle prior to being measured. A little reading up on HMI reveals that this particular interpretation understands probability to be entirely epistemic (our ignorance or inability to measure everything accurately) and not ontological or fundamental.

My understanding is that decoherence has to do with normal macroscale objects, such as detectors, interacting with isolated quantum systems, which are fundamentally probabilistic, or at least the math describes those systems as being so, causing them to lose their coherence, leaking the quantum information out into the wider environment.

But it doesn't do away with superposition. In the cat thought experiment, although it explains why we don't see both a live and dead cat when opening the box, it doesn't explain what happens to us and the rest of the universe. That still requires an interpretation, and I believe MWI is compatible with decoherence.

ou're right that there's no need for it in the context of a discussion about the 'measurement problem' (which I'm guessing this thread is somewhat related to, but I'm still very unsure of that), — andrewk

At the beginning of the talk I linked to, Alan Bar introduced the measurement problem for the audience, then Simon Saunders argued for MWI, followed by James Binney discussing HMI, I guess, although he didn't give his interpretation a name. The Youtube title is: "The 1st Ockham Debate - The Problem of Quantum Measurement - 13th May 2013".

There are no particles as such prior to the act of measurement. Literally all there is is the possibility of there being one. — Wayfarer

I don't know what that means, though, unless one is an anti-realist, which I'm not.

It is the measurement which reduces the probability to actuality. — Wayfarer

But how do you go from probability to actuality? What is the mechanism? Is this just brute?

That is not historically accurate, and you really need to stop pretending quantum mechanics is a "model", it's not, it's a theory i.e. a statement about what exists in reality, how it behaves and why. — tom

Alright point taken, but the question is whether the Schrödinger equation is describing the real state of the particle before it's measured, or it just has predictive power as a useful tool, and the reality is something else. Afterall, what the hell is a probability wave supposed to be?

In context of Binney and HMI, if the reality would be our epistemic uncertainty about the complex state of the measuring device having a large influence on the particle it's detecting.

If MWI is the case, then probability wave is a description of other worlds. Or it could be pilot waves guiding the particle. But then again, perhaps reality is a jumble of possibilities when we're not looking? Question is why does measurement make it classical? Why is our lived experience mostly classical?

so far as as the"measuring device" is concerned, and I'm quite surprised that Binney does not recognize it, exactly what are the boundaries to the "measurement device" and how do you ever establish its state if it is constantly changing? — Rich

That is a big problem. Perhaps as big as not being able to detect other worlds or pilot waves.

However, for science the math is what counts — Rich

Science isn't math though. It's an empirical investigation of the various phenomena in the world. As such, the world has the final say, not math. Experiments and observation are what ultimately drive the math.

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.