When you eventually respond, you will likely do so with the hope that your response is creative enough and convincing enough to sway me closer to your point of view. Though what I've just said will definitely influence your choice of words...

Ruminate.

I see you've run out of logical arguments to support your point of view. Like I said, determinism wins (for now)!

Understanding life has nothing to do with logic. Logic is a parlor game to occupy the creative mind, no different than any other game.

What I am suggesting to you, and do what you choose, is to ruminate on "I am considering". But there is nothing wrong with games, it's just that I'm not into it right now.

Agreed, the outcome of this discussion will not affect how I live my life. Unfortunately, I have a brain that only seems to accept logic, evidence, and probability when it comes to establishing belief. But I love logic and games, so that's a plus! :)

Learning new skills and learning in general makes life full and wondrous. If you are ever so inclined try out ruminating, it is the first step into philosophy, or you can try out dancing or drawing which is a step into the creative arts. But if you don't, you don't, there is always the next life. There is no rush.

Provide references and I'll see if I have the time to study it. — Rich

Here's a talk by David Wallace (philosopher of physics) where he gives the reasoning for treating quantum states as real with reference to the MZI experiments. It's aimed at a general audience.

Here's a longer and more technical version of the above talk that gets into the math and philosophical/foundational issues. He discusses ontology (first video), Occam's razor (at 48 mins) and probability (second video).

Still, quantum theory remains probabilistic though in Bohm's model there are real causal agents - including "information". — Rich

There are similarly real causal agents in Many-Worlds. Quantum mechanics describes and predicts the behavior of quantum systems, it doesn't prescribe it.

Thanks I'll check them out when I have called chance, but they is nothing Occam about infinite worlds meta-world. And even if one was taken by such a interpretation, our world remains probabilistic. There is no undoing Schrodinger's equation at this time and no evidence that it is in any jeopardy.

I watched the parts of the videos. There is nothing new in them. He is just proposing that photons should be considered real and that is what Bohm mechanics does. The equations remain the same, there is no determinism. One can speculate about infinite worlds growing infinitely with each passing quantum event or one can just work with Bohmian mechanics which is in this world and subject to experimental verification. It depends upon how one wishes to spend one's life.

However, there were some interesting comments about how this whole theory of infinite worlds is entirely faith base - and it is and always will. It is fundamentally impossible to test just like God.

There's a nice apocryphal story about Wittgenstein there in the first lecture. For those who don't want to watch the vid, it goes something like this:

Wittgenstein once asked a colleague: "Why were people so surprised to discover that the Earth is spinning and not that the Sun goes around the Earth?" His colleague replied that, well, it kind of looks like the Sun goes around the Earth, doesn't it? To which Wittgenstein shot back: "Well, what would it look like if it looked like the Earth was spinning?"

And the answer, of course, is that it would look like exactly like it does look like, exactly like it looked like back when people thought that the Sun was going around the Earth.

So I want to ask you. You keep saying that the Mach-Zehnder interferometer experiment would be inexplicable under any interpretation other than the Everett interpretation. So what do you think the result of the experiment would look like if the Bohm or the Copenhagen interpretation was true?

So I want to ask you. You keep saying that the Mach-Zehnder interferometer experiment would be inexplicable under any interpretation other than the Everett interpretation. So what do you think the result of the experiment would look like if the Bohm or the Copenhagen interpretation was true? — SophistiCat

My argument using the MZI experiment is against non-deterministic interpretations.

According to such interpretations, the photon always turns up at the same detector (with certainty), but without a sufficient cause. So God not only plays dice but he always rolls a six.

The result of the experiment would look the same. But the result would be inexplicable.

I don't understand. If an interpretation gives us the correct result (i.e. the result predicted by the formalism and validated by experiments), then where is the problem? Or are you under the impression that a "non-deterministic interpretation" is contractually obligated to give a non-deterministic result for every conceivable measurement?

Perhaps you can work an example in one of these interpretations and show where exactly the problem lies.

[

According to such interpretations, the photon always turns up at the same detector (with certainty), but without a sufficient cause. So God not only plays dice but he always rolls a six. — Andrew M

Every interpretation uses the Schrodinger equation or equivalent (Bohmian is equivalent).

They all would necessarily predict the same results. Bohmian is causal but not deterministic but no different in results.

Are you suggesting that there is an interpretation that doesn't use the same Schrodinger/Bohmian equations and is getting better predictions?

I listened to the lecture. Other than pushing his open interpretation, which sounds great in a lecture because who doesn't love an infinite worlds model with all like the science fiction possibilities, there was nothing new.

I don't understand. If an interpretation gives us the correct result (i.e. the result predicted by the formalism and validated by experiments), then where is the problem? Or are you under the impression that a "non-deterministic interpretation" is contractually obligated to give a non-deterministic result for every conceivable measurement? — SophistiCat

No. It is in principle possible that Alice could roll a dice a million times and get a six every time. That result is no less likely than any other string of results for a million rolls. But her non-random-looking result begs for an explanation in a way that random-looking results don't.

So the Copenhagen interpretation correctly predicts that a photon in the standard MZI experiment will always end up at the first detector despite passing through beam splitters. But that raises the question as to why. What is the causal explanation for that non-random-looking result?

For the Copenhagen interpretation, the Schrodinger equation is equivalent to asserting that Alice just always rolls sixes. Each formalism gives the correct predictions and no causal explanation exists.

The problem is with the plausibility of that idea.

Bohmian is causal but not deterministic — Rich

What is the difference between causal and deterministic here? Is there a sufficient cause for the photon always ending up at detector 1? Or is it just a chance occurrence in each instance?

Are you suggesting that there is an interpretation that doesn't use the same Schrodinger/Bohmian equations and is getting better predictions? — Rich

No.

What is the difference between causal and deterministic here? — Andrew M

Bohm realized there are initial causes (e.g. the mind) but the results were probabilistic not determined. On only had to look at the equations to understand this. As for where the photon end up is predicted by either the Schrodinger equation its Bohmian mechanics counterpart. Both are the equivalent.

There is nothing in the video that contradicts any aspect of quantum theory, he was just making a pitch for his theory and based upon the comments some see it as faith (as I do) and others view it as speculation (that is unverifiable).

I don't know why you keep referring to the Schrodinger equations as random when they are clearly probabilistic (if they were random, then the equation would be useless, one might as well throw dice). Why do you continue to insist that quantum theory = randomness? It's really strange.

Why do you continue to insist that quantum theory = randomness? — Rich

I'm not saying that at all. On the Everett interpretation, the quantum state contains the complete information about the system and that state evolves deterministically.

On the standard de Broglie-Bohm interpretation, the quantum state does not contain the complete information about the system. Nonetheless a photon has a specific position and momentum and follows one specific trajectory as governed by the pilot wave.

Is that your view?

Nonetheless a photon has a specific position and momentum and follows one specific trajectory as governed by the pilot wave. — Andrew M

Bohm does not use the concept of a pilot wave. This concept is ancient as far as Bohm's interpretation is concerned. It is the quantum potential that is real and the electron can be considered a perturbation in this potential. There is no specific position and momentum because the potential is subject to "new information", such as an observation.

It is necessary to discard the concept of "things" (as determinists continue to insist on) and treat quantum as a process that is in continuous flux. How does a process become a thing? That is exactly the role of the mind as it seeks to create a canvas to create on.

No. It is in principle possible that Alice could roll a dice a million times and get a six every time. That result is no less likely than any other string of results for a million rolls. But her non-random-looking result begs for an explanation in a way that random-looking results don't.

So the Copenhagen interpretation correctly predicts that a photon in the standard MZI experiment will always end up at the first detector despite passing through beam splitters. But that raises the question as to why. What is the causal explanation for that non-random-looking result?

For the Copenhagen interpretation, the Schrodinger equation is equivalent to asserting that Alice just always rolls sixes. Each formalism gives the correct predictions and no causal explanation exists.

The problem is with the plausibility of that idea. — Andrew M

It is true that an infinite sequence of sixes is a possible outcome of an infinite sequence of die rolls. But that doesn't change the fact that the probability of each such roll is given as 1/6 by the theory that the die is fair.

In the MZI experiment the standard quantum mechanics calculation gives the probabilities at the detectors as 0 and 1. Any interpretation of quantum mechanics had better yield the same probabilities, otherwise it doesn't even qualify as an interpretation. Are you saying that the Copenhagen interpretation predicts probabilities other than 0 and 1 in this case, or fails to predict anything specific?

(As an aside, this very special case where probabilities neatly collapse into all or nothing is uniquely favorable to the Everett interpretation, which otherwise faces a prima facie problem with specific observed frequencies of outcomes. In contrast to the Copenhagen interpretation, which happily assumes the reality of probabilistic outcomes as a matter of principle, the Born rule is difficult to justify in the context of Many Worlds. When they are not making popular presentations, like the one by David Wallace that you linked, Everettians tie themselves into knots trying to make sense of these probabilities. And this is where, I am afraid, the prima facie appeal of the MWI as the "no-interpretation" interpretation dissipates.)

It is necessary to discard the concept of "things" (as determinists continue to insist on) and treat quantum as a process that is in continuous flux. How does a process become a thing? That is exactly the role of the mind as it seeks to create a canvas to create on. — Rich

We perceive things that emerge as the result of dynamic processes. So we may more-or-less agree here.

Also, it seems to me that what you mean by non-determinism isn't an absence of sufficient causality (since you deny randomness), but simply that causal agents can exercise autonomy. Which I agree with.

If we do agree, then our substantial difference is really over whether actions in the universe can be non-local. But I'll leave it there for now.

Yes, I agree. Thanks.

n the MZI experiment the standard quantum mechanics calculation gives the probabilities at the detectors as 0 and 1. Any interpretation of quantum mechanics had better yield the same probabilities, otherwise it doesn't even qualify as an interpretation. Are you saying that the Copenhagen interpretation predicts probabilities other than 0 and 1 in this case, or fails to predict anything specific? — SophistiCat

The Copenhagen interpretation makes the same prediction but it denies that there is a causal explanation for the probabilities. But, if causality is assumed, then the MZI experiment shows that a beam splitter cannot be sending a photon exclusively one way or the other with 0.5 probability (or else a photon would arrive at either detector with 0.5 probability, not 0 and 1). So there must be some underlying causal factor operating in beam splitters in the same way that there must be some underlying causal factor operating in Alice (or her die) such that she always rolls sixes.

(As an aside, this very special case where probabilities neatly collapse into all or nothing is uniquely favorable to the Everett interpretation, which otherwise faces a prima facie problem with specific observed frequencies of outcomes. In contrast to the Copenhagen interpretation, which happily assumes the reality of probabilistic outcomes as a matter of principle, the Born rule is difficult to justify in the context of Many Worlds. When they are not making popular presentations, like the one by David Wallace that you linked, Everettians tie themselves into knots trying to make sense of these probabilities. And this is where, I am afraid, the prima facie appeal of the MWI as the "no-interpretation" interpretation dissipates.) — SophistiCat

I don't think it follows from "no-interpretation" that the natural interpretation should be trivial and obvious. A case in point is that it was decades before the Everett interpretation arrived on the scene.

Anyway, the partial Everettian answer is that the probability describes a system's self-locating uncertainty when it interacts with another system (e.g., whether a photon finds itself in the reflection path or transmission path of the beam splitter). So it is directly related to the physical processes of splitting and interference. This is nicely characterized by the second beam splitter in the MZI experiment where both processes are involved.

The Copenhagen interpretation makes the same prediction but it denies that there is a causal explanation for the probabilities. But, if causality is assumed, then the MZI experiment shows that a beam splitter cannot be sending a photon exclusively one way or the other with 0.5 probability (or else a photon would arrive at either detector with 0.5 probability, not 0 and 1). — Andrew M

You do not need to assume causality, or anything else besides the operation of standard quantum mechanics, in order to obtain that result. You said so yourself: the Copenhagen interpretation makes the same prediction. It follows the standard solution all the way up to the moment of detection, at which point it says that the superposition state collapses into one of the eigenstates - acausally, as you say, but following the Born rule for probabilities. And since in this case the superposition is degenerate, the result is perfectly predictable, even assuming the Copenhagen interpretation: the wavefunction has to collapse into one particular position eigenstate with probability 1, simply because there is only one non-zero eigenvalue. So where do you get probability 0.5? And what does this have to do with causality? I don't understand.

All new ideas stem from the inputs that precede them - they aren't magically generated from nothingness. — CasKev

And you know that how?

@Janus More a hypothesis than a known fact... ;)

But try to think of an idea you've had that was completely brand new, and not based on a combination of knowledge and experience of past events...

But try to think of an idea you've had that was completely brand new, and not based on a combination of knowledge and experience of past events... — CasKev

I do it all the time. That is what I got paid for when I was a consultant. Past experiences (memory) ≠ Creativity and Influence ≠ Determine.

An example of creative: the idea that there are natural laws determining everything. That is a completely creative thought (a few hundred years old) that was derivative of an omnipotent God, but the creative idea was to simply replace natural laws for the word God. This is how the creative mind works. The goal of course was to give atheists something that they could believe in, and they do. It really is a matter of faith.

Einstein did believe quite fervently in natural laws which is why he said "God does not play dice"., If you catch my drift?

You do not need to assume causality, or anything else besides the operation of standard quantum mechanics, in order to obtain that result. You said so yourself: the Copenhagen interpretation makes the same prediction. It follows the standard solution all the way up to the moment of detection, at which point it says that the superposition state collapses into one of the eigenstates - acausally, as you say, but following the Born rule for probabilities. And since in this case the superposition is degenerate, the result is perfectly predictable, even assuming the Copenhagen interpretation: the wavefunction has to collapse into one particular position eigenstate with probability 1, simply because there is only one non-zero eigenvalue. — SophistiCat

I agree with all you say above but would add that the probabilities themselves also have no causal explanation under the Copenhagen interpretation (i.e., the Born rule is postulated).

So where do you get probability 0.5? And what does this have to do with causality? I don't understand. — SophistiCat

This is when considering a single beam splitter in isolation. When one photon is sent into a beam splitter, there are two position eigenstates - one for the reflection path and one for the transmission path with 0.5 probability for each.

The MZI experiment shows that this cannot be the scenario at the second beam splitter. If only one photon were entering the second beam splitter, then a photon should be found at the second detector half the time. But it's not. This is what I was trying to convey with the "Alice rolling sixes" analogy. It is highly improbable that on multiple runs a single photon entering the second beam splitter would always be found at the first detector purely by chance.

But this is what the Copenhagen interpretation is committed to by denying causality. The results that it predicts are inherently inexplicable on its own premise.

So, if not one photon, then what is entering the second beam splitter? Well, the wave function tells us exactly what is happening. It says there is a photon entering a beam splitter from the upper path and a photon entering a beam splitter from the lower path. Those states in turn split, two of the states destructively interfere and the other two states constructively interfere resulting in a final state with probability 1.

The point is that everything that went into your decision is based on something that existed prior to the decision. Even seemingly random events have a preceding chain of events leading up to them. — CasKev

That there was a preceding chain of events is obvious, but that doesn't mean the earlier state caused the subsequent state. That is, universe at state A doesn't physically entail state B.

Regardless, whether a choice were determined or random, in neither event is the agent reponsible for it.

I don't know about that, but ideas are certainly usually expressed in some familiar language, whether linguistic, visual, or auditory.

I agree with all you say above but would add that the probabilities themselves also have no causal explanation under the Copenhagen interpretation (i.e., the Born rule is postulated). — Andrew M

That's true. But having postulates is no sin in itself: any theory relies on some postulates. The important thing is that the Born rule postulate in the Copenhagen interpretation does not clash with its narrative.

This is when considering a single beam splitter in isolation. When one photon is sent into a beam splitter, there are two position eigenstates - one for the reflection path and one for the transmission path with 0.5 probability for each.

The MZI experiment shows that this cannot be the scenario at the second beam splitter. If only one photon were entering the second beam splitter, then a photon should be found at the second detector half the time. But it's not. This is what I was trying to convey with the "Alice rolling sixes" analogy. It is highly improbable that on multiple runs a single photon entering the second beam splitter would always be found at the first detector purely by chance.

But this is what the Copenhagen interpretation is committed to by denying causality. The results that it predicts are inherently inexplicable on its own premise. — Andrew M

No, this is what we would be committed to if we interpreted light as a flow of classical particles. But the Copenhagen interpretation does not do that. It is committed to the same thing that the fully-quantum theory is committed to, plus a little extra - but that extra does not show up until the measurement occurs at the detectors, at which point the "extra" makes no observable difference.