@apokrisis

Some say it is going back to CI. But for me, that is ontic in that it puts the observer - or at least, points of view - in the spotlight as the critical factor.

So for you the "shut up and calculate" approach of some of those who support CI is no longer an option under these new "Bayseian" interpretations?

Quantum Mechanics Unscrambled.
Just read it. Overly complicated - one suspects that at some points he is just showing off that he's technically proficient with QM formalism and complex analysis - and it is almost entirely devoid of any metaphysics, so I wouldn't bother wasting your time, unless you are interested in the technical idea that QM theory can be reshaped as a new kind of probability theory. At a couple of points he touches on the idea that what these "novel" approaches are proposing is just some kind of instrumentalism/operationalism, but he does nothing to actually argue that they should not be taken in precisely that kind of way.

she can still control those probabilities by means of the prior set up. — Pierre-Normand

I'm over my head here. But I've seen MWI described as superdeterministic. https://en.wikipedia.org/wiki/Superdeterminism
The future of all measurements is already known it's just that you happen to be in the one where the train of thought has completed. Presumably the worlds where your train of thought gets completed are the ones that are relatively normal with the illusion of the higher level regularities (breathable atmosphere ect). In that sense notions of identity and control are eliminable or instrumental.
I understand some say that it is not true and the state of things are that there are more (normal) worlds which is why when you think: "I raise my arm" the arm does go up rather than say your leg because there are more of the former than the latter. But I'm not sure why that is (more worlds of a certain kind than others).
The constraint based physics being posted by Apokrisis here makes more intuitive sense to me but what seems intuitive might not be true.

I'm over my head here. But I've seen MWI described as superdeterministic. https://en.wikipedia.org/wiki/Superdeterminism
The future of all measurements is already known it's just that you happen to be in the one where the train of thought has completed. — JupiterJess

My argument, which was relying on the partial acceptance of the compatibilist notion of free will, addresses the sort of challenge posed by superdeterminism. What it is that evolves superdeterministically, on such a conception of the 'multiverse', never is, as you note, the trajectory of a conscious observer but rather the state vector which represents the 'state' of the whole multiverse. The effect from the manifold 'spitting' of observers over time ought not to be anymore troublesome to a compatibilist conception of free will than is the fact that, within any determinate history of a single observer, there are unlikely events that occasionally occur as the outcome of the uncontrolled amplification of quantum fluctuations. This is not sufficient to remove the agent's control where it matters, except in very restricted and artificial situations, since not all features of the emergent classical domain are subject to such uncontrollable fluctuations.

Presumably the worlds where your train of thought gets completed are the ones that are relatively normal with the illusion of the higher level regularities (breathable atmosphere ect). In that sense notions of identity and control are eliminable or instrumental.
I understand some say that it is not true and the state of things are that there are more (normal) worlds which is why when you think: "I raise my arm" the arm does go up rather than say your leg because there are more of the former than the latter. But I'm not sure why that is (more worlds of a certain kind than others).

To be honest, I am not sure either in what way, exactly, many-worlders account for the empirical verification of the Born rule in the individual 'worlds' (or individual splitting world-lines) of the agents/obervers (and it is a problem that used to trouble me greatly when I was myself a fan of David Deutsch and of many-world interpretation) but that is a problem that is quite distinct from the problem of superdeterminism (as it allegedly relates to the free will debate).

The constraint based physics being posted by Apokrisis here makes more intuitive sense to me but what seems intuitive might not be true

I am quite sympathetic also with the main drift of Apokrisis's constraint-based approach. But I think is it quite congenial to the pragmatist (or relational) interpretation of QM that I also favor over the alternative metaphysically 'realist' interpretations. It is indeed thanks to thermodynamical constraints that the structured and controllable 'classical world' emerges at all from the chaos of the homogeneous gas of the early expanding universe.

Quantum Mechanics Unscrambled.
Just read it. Overly complicated - one suspects that at some points he is just showing off that he's technically proficient with QM formalism and complex analysis - and it is almost entirely devoid of any metaphysics, so I wouldn't bother wasting your time, unless you are interested in the technical idea that QM theory can be reshaped as a new kind of probability theory. At a couple of points he touches on the idea that what these "novel" approaches are proposing is just some kind of instrumentalism/operationalism, but he does nothing to actually argue that they should not be taken in precisely that kind of way. — jkg20

(We are veering a bit off-topic...)

I've now read about two thirds of it and let me demur. It seems to be an excellent paper. Rather than it being devoid of metaphysics I would rather say that it targets with great accuracy the metaphysical prejudices that sustain some of the most popular interpretations of QM. From what I see, he also is rather careful to distinguish his own pragmatist account from the cruder forms of positivism that it now has become fashionable to ascribe to Bohr and to Heisenberg. It is not entirely unfair to charge Bohr himself with operationalism but Delhôtel (just like Bitbol before him) also is careful to disclaim the idea of reducing quantum phenomena to classical 'observables'. He rather deflates the metaphysical implication of the quantum formalism through displaying how the generality and empirical adequacy of this formalism derives (and, indeed, can be mathematically derived) from principles that apply to classes of experimental contexts that obey some very general pragmatic requirements (such as the necessity to account for phenomena that are partially constituted and/or produced by the very circumstances of their observation) and simple norms of logical consistency.

I am getting to the point where Delhôtel seemingly is going to distinguish his approach from Bitbol's own approach (developed in Quantum Mechanics as Generalised Theory of Probabilities). This is quite interesting. I'll comment later.

So, can it be affirmatively asserted that QM affirms the concept of having a 'free will'? — Posty McPostface

No. That's more a conceptual/philosophical issue that one brings to QM. And, as it happens, the Schrodinger equation is deterministic.

The Schrödinger equation describes the (deterministic) evolution of the wave function of a particle. — Wikipedia

For fun, you might like Conway and Kochen's free-will theorem that basically says that if we have free-will then so do particles. But note that free-will, as Conway and Kochen define it, just means that the outcome is not determined by the prior history of the universe.

So for you the "shut up and calculate" approach of some of those who support CI is no longer an option under these new "Bayseian" interpretations? — jkg20

Huh? Of course an epistemic instrumentalism is always a sound default position here. So I'm fine if that suits people's needs. But I personally am interested in the metaphysical story. Which should be OK too - especially given that this is a philosophy forum.

And QM is moving towards that kind of interpretation with the quantum information or quantum reconstruction projects. MWI and Bohmian Mechanics are the last gasp of an out-dated way of conceiving of physicalism. Their advocates are especially passionate probably because they know they are a passing story. :) — apokrisis

It takes a theory to beat a theory... I think David Wallace's comments are worth reading on this subject (particularly his answers to Q9 and Q10).

I’d also say that I don’t see how reconstruction could reduce the need for interpretation. Ultimately, however we reconstruct quantum mechanics, we’re either going to end up saying (i) that the mathematical structure thus reconstructed represents physical reality faithfully (in which case we end up with the Everett interpretation or something like it), or (ii) that it represents physical reality incompletely or inaccurately (in which case we need to fix it, which leads us to hidden-variable or dynamical-collapse theories), or (iii) that it’s not in the business of representing physical reality at all (which leads us to operationalist or neo-Copenhagen or physics-is-information approaches). — Interview with David Wallace

And yet infinitely often, the zero-amplitude strikes will also happen in some worldline of the observer. Which screws any claim to have done something which has constrained the probabilities to these observed bands. — apokrisis

Zero-squared is still zero, experimental imprecisions aside.

Under MWI, there will be infinitely many worlds in which all the bands are composed of the least likely events. So the bands will be exactly where they shouldn't be for an infinity of observers.

If you take MWI seriously, you can't take the probabilistic success of QM seriously. Everything that can happen, happens infinitely often. — apokrisis

It doesn't have to be that way. You can reject actual infinities and consider limits such as Planck-length and light-speed to constrain the locations a particle can be in since it was last measured. As Max Tegmark, who advocates MWI, says:

Yet real numbers, with their infinitely many decimals, have infested almost every nook and cranny of physics, from the strengths of electromagnetic fields to the wave functions of quantum mechanics. We describe even a single bit of quantum information (qubit) using two real numbers involving infinitely many decimals.

Not only do we lack evidence for the infinite but we don’t need the infinite to do physics. — Infinity Is a Beautiful Concept – And It’s Ruining Physics - Max Tegmark

The effect from the manifold 'spitting' of observers over time ought not to be anymore troublesome to a compatibilist conception of free will than is the fact that, within any determinate history of a single observer, there are unlikely events that occasionally occur as the outcome of the uncontrolled amplification of quantum fluctuations. This is not sufficient to remove the agent's control where it matters, except in very restricted and artificial situations, since not all features of the emergent classical domain are subject to such uncontrollable fluctuations. — Pierre-Normand

This is where we - SX included - agree. Just on the physics of brains alone, quantumness doesn't come into it as there is no evidence to suggest that consciousness depends on some kind of clever amplification of fluctuations. Instead, the brain would appear to rely on a routine thermal suppression of those fluctuations.

Furthermore, I argued on the grounds of biosemiotics or standard biological theory that life and mind are further insulated from physics in toto to the degree they are informational processes. So quantum or classical - it doesn't make a difference to the degree that brains are processing signs, doing some kind of neural computation, and so cognition would be a multi-realisable function. The algorithms could be implemented in any kind of hardware in principle.

Having stated that general case, then come the critical caveats. An enactive or biosemiotic view of cognition does argue that brains aren't actually computers. Symbol and matter, software and hardware, are entangled in a structural relationship tide to the embodied purposes of Darwinian flourishing, and more generally, entropy gradient dissipation.

And then still more crucially, biophysics reveals that the actual physical basis of life and mind is the nanoscale quasi-classical realm where the quantum and the classical phases of existence are in a poised state of critical instability. Organic chemistry in room temperature water has some very special properties that do explain how life and mind - as semiotic structures - could even exist.

So a little ironically, it is not about either the classical or the quantum realm. Consciousness, as what brains do, has its roots in the existence of a quasi-classical transition zone where the physics still swings both ways.

Does that make freewill now a quasi-classical phenomenon? Well no. As I argued earlier, freewill is a much higher level socially constructed deal. It is about the construction of a "thinking self" that negotiates between a set of established cultural norms around behaviour, and some set of needs and feelings that represent "our selves" as a biological and psychological individual within that wider framework.

Freewill is a contra-causal thing because that is just a basic logical requirement. It needs to be based in counterfactual thinking to allow the needs of society vs the needs of the individual to even get negotiated and arrive at some pragmatic balance.

So what we end up with here is a thread of semiotics - a balance of integration and differentiation - that starts right down in maximal simplicity of the quantum mechanics and continues with ever greater elaboration all the way up to the massive complexity of humans living as social creatures.

There are the disjunctions that separate, but then also the relations that still connect.

And a constraints-based metaphyics accounts for that. It finds its foundations not in some ground - whatever it is that sits at the level immediately below the level in question - but in the fact that there is some boundary between two levels ... a boundary with the third thing of a bridging relation.

So it is the irreducibly triadic relation which is the grounding thing.

Which is also why a quantum interpretation that focuses on the observer rather than the observables, the complex epistemic relation rather than the simple ontic facts or events, would be the way forward.

Zero-squared is still zero, experimental imprecisions aside. — Andrew M

Well, Pierre-Normand was talking about almost zero amplitudes. But that is all part of the fudging when it comes to calculating using infinities. It is part of the same can of worms.

It doesn't have to be that way. You can reject actual infinities and consider limits such as Planck-length and light-speed to constrain the locations a particle can be in since it was last measured. As Max Tegmark, who advocates MWI, says: — Andrew M

There you go! That's what I am talking about - accepting actual cut-offs in principled fashion. I find it encouraging that Tegmark is blogging in a way that sounds like confessing his sins. :)

... Does that make freewill now a quasi-classical phenomenon? Well no. As I argued earlier, freewill is a much higher level socially constructed deal. It is about the construction of a "thinking self" that negotiates between a set of established cultural norms around behaviour, and some set of needs and feelings that represent "our selves" as a biological and psychological individual within that wider framework. — apokrisis

Yes, I quite agree; and so do I with most of the rest of your excellent post, with only minor reservations...

Which is also why a quantum interpretation that focuses on the observer rather than the observables, the complex epistemic relation rather than the simple ontic facts or events, would be the way forward.

Indeed!

I'm over my head here. But I've seen MWI described as superdeterministic. https://en.wikipedia.org/wiki/Superdeterminism — JupiterJess

Superdeterminism is a one-world theory that apparently has about three supporters including 't Hooft. It basically says that if you have a beam splitter, then it is predetermined which way the particle will go. Whereas Many Worlds says a particle goes both ways.

Bell's Theorem makes three assumptions - locality, classical realism (counterfactual definiteness) and freedom-of-choice (in what measurement to perform).

Superdeterminism rejects freedom-of-choice. Many Worlds rejects counterfactual definiteness.

There you go! That's what I am talking about - accepting actual cut-offs in principled fashion. I find it encouraging that Tegmark is blogging in a way that sounds like confessing his sins. :) — apokrisis

In his defense, he does note that infinity seduced him at an early age...

I am quite sympathetic also with the main drift of Apokrisis's constraint-based approach. But I think is it quite congenial to the pragmatist (or relational) interpretation of QM that I also favor over the alternative metaphysically 'realist' interpretations. It is indeed thanks to thermodynamical constraints that the structured and controllable 'classical world' emerges at all from the chaos of the homogeneous gas of the early expanding universe. — Pierre-Normand

I'm not sure that you and Apo are saying anything very different to MWI proponents such as David Wallace regarding a preferred basis, emergence and pragmatism. For Wallace, worlds aren't postulated in the quantum formalism, they are stable structures that emerge via decoherence.

So the decoherence basis is the preferred basis for all of us that are here to observe those emergent structures (the view from somewhere). But at a lower-level, there is no preferred basis - any way of factoring things is valid. It's just that not every way of factoring things necessarily persists to form macroscopic structures that we can observe.

As Wallace puts it (before going on to describe higher-order ontology and the role of structure):

Advocates of the Everett interpretation among physicists (almost exclusively) and philosophers (for the most part) have returned to Everett’s original conception of the Everett interpretation as a pure interpretation: something which emerges simply from a realist attitude to the unitarily-evolving quantum state.

How is this possible? The crucial step occurred in physics: it was the development of decoherence theory.

...

For decoherence is by its nature an approximate process: the wave-packet states that it picks out are approximately defined; the division between system and environment cannot be taken as fundamental; interference processes may be suppressed far below the limit of experimental detection but they never quite vanish. The previous dilemma remains (it seems): either worlds are part of our fundamental ontology (in which case decoherence, being merely a dynamical process within unitary quantum mechanics, and an approximate one at that, seems incapable of defining them), or they do not really exist (in which case decoherence theory seems beside the point).

Outside philosophy of physics, though (notably in the philosophy of mind, and in the philosophy of the special sciences more broadly) it has long been recognised that this dilemma is mistaken, and that something need not be fundamental to be real. In the last decade, this insight was carried over to philosophy of physics. — The Everett Interpretation - David Wallace

The value of relational QM, I think, is that it gives us a language for talking about the familiar world that we observe from our individual point-of-view rather than an idealized view-from-nowhere. Which is to say, we are each participants in a localized part of a much larger quantum universe that evolves unitarily.

The value of relational QM, I think, is that it gives us a language for talking about the familiar world that we observe from our individual point-of-view rather than an idealized view-from-nowhere. Which is to say, we are each participants in a localized part of a much larger quantum universe that evolves unitarily. — Andrew M

Thanks for the reference to Wallace on Everett's interpretation. I just looked up his book The Emergent Multiverse: Quantum Theory According to the Everett Interpretation. The second part of the book, entitled Probability in a Branching Universe is of much interest to me. There is a short discussion on pp. 135-137 on the (pseudo-)problem of free will in the context of Everett's interpretation that I'm heartened to see appears consistent with my prior take on it in this thread. There is some discussion of the preferred basis problem that I will also look into. I'll postpone the task of making more explicit the grounds for my dissatisfaction with the metaphysical underpinnings of the multiverse approaches to quantum theory. I still have much ongoing readings to finish.

The value of relational QM, I think, is that it gives us a language for talking about the familiar world that we observe from our individual point-of-view rather than an idealized view-from-nowhere. — Andrew M

Let me just note that Rovelli and Bitbol both endorse relational approaches that share some features with Everett's interpretation. But they don't reify the multiverse anymore than they do its branches.

Are neurons evolved to exchange signals or potentials?

Let’s stop mucking about.

My point was just meant to highlight that quantum level mechanics isn't needed to model or characterize the physical aspects involved in neural signal generation, exchange, and population level interpretation; classical mechanics (which is what I should have said, not newtonian) is sufficient for that. Quantum indeterminacy, which (as far as I know) is inability to fully characterize the state of an isolated quantum system, doesn't impact, in any meaningful way, the behavior of systems describable by classical mechanics which includes brains and neurons. The semiotic discussion is separate from this and I just wanted to make it clear.

Going to the semiotic point, you are saying that information processing laws are independent of material substrate and they are needed in addition to biophysical and chemical constraints to make sense of neural processing. I agree on this but then it seems like there is another point you make - that all questions or most every question in neuroscience has to do with neural semantics and natural mechanisms don't play any meaningful explanatory role in how or why a given neuro phenomenon or function is the way it is. My point is that mechanisms matter for explaining how brains work.

Thanks for the reference to Wallace on Everett's interpretation. I just looked up his book The Emergent Multiverse: Quantum Theory According to the Everett Interpretation. The second part of the book, entitled Probability in a Branching Universe is of much interest to me. — Pierre-Normand

You may also be interested in Carroll and Sebens' derivation of the Born rule which Sean Carroll discusses on his blog.

Let me just note that Rovelli and Bitbol both endorse relational approaches that share some features with Everett's interpretation. But they don't reify the multiverse anymore than they do its branches. — Pierre-Normand

I think emergent branching aside, what is fundamental are the relative states of the wave function. In this respect, Rovelli's RQM is essentially equivalent to the Everett interpretation (it's unitary, local, complete, non-classical, etc.), except it uses relational terminology to index all descriptions to the observer.

Point taken. I was just wondering whether you thought that these latest approaches to QM actually had metaphysical consequences that took instrumentalism off the table.

(We are veering a bit off-topic...)

Agreed. I will reread the paper and perhaps start a new thread. Whilst the author certain says that his position should be distinguished from what he refers to as "crude operationalism" (which may be a straw man in any case) just saying that his position should be so distinguished doesn't make it distinguishable.

QM is quite a diverse range of ideas.
Perhaps you should give a brief definition of what you mean by QM.

For myself, I can only positivistically affirm quantum time and quantum energy.
But consider this:
If we made a machine that analyzed all your atoms so that it could perfectly predict your behavior
would you not go out of your way to defy it?

For myself, I can only positivistically affirm quantum time and quantum energy. — Jonathan AB

How do you do that?

One does not need QM to prove the absence of free will. Special relatively already achieves this without equivocation. Temporal shifts at high velocity travel have proven special relatively correct. The future already exists and as such free will is precluded.

One does not need QM to prove the absence of free will. Special relatively already achieves this without equivocation. Temporal shifts at high velocity travel have proven special relatively correct. The future already exists and as such free will is precluded. — Marcus de Brun

But quantum mechanics tells us that we don't inhabit a space-time, rather we inhabit a multiverse, which to a good approximation, is a countably infinite set of parallel space-times. Under this scenario, while the futures already exist, just as in general relativity, our personal future is open.

If the future exists apriori how can our personal future be open.?

This multiverrse stuff sounds like a sophisticated version of the god delusion... A nice way of filling in gaps and silencing critics. Other Universes are not relavent to our universe and discussions as to their existence are just another example of atheistic gods.

Bell himself felt the ultimate question is one of determinism, and the only problem with determinism is the fact that people are afraid of it and don't know what to do with it, and cannot reconcile it with thought, or free will. It (determinism) is readily reconcilable with SR and QM, it its less reconcilable with the fear of its intellectual import.

If the future exists apriori how can our personal future be open.? — Marcus de Brun

It is impossible in principle to know which futures you will inhabit, not even a "god" can do that. Also, it is possible to set the quantum amplitude of certain futures to zero by the application of knowledge.

This multiverrse stuff sounds like a sophisticated version of the god delusion... A nice way of filling in gaps and silencing critics. Other Universes are not relavent to our universe and discussions as to their existence are just another example of atheistic gods. — Marcus de Brun

Sure, you are willing to declare reality is a space-time based on special relativity, but are unwilling to accept what quantum mechanics tells us. Strikes me as glaringly inconsistent.

Bell himself felt the ultimate question is one of determinism, and the only problem with determinism is the fact that people are afraid of it and don't know what to do with it, and cannot reconcile it with thought, or free will. It (determinism) is readily reconcilable with SR and QM, it its less reconcilable with the fear of its intellectual import. — Marcus de Brun

QM is a fully deterministic theory.

It is impossible in principle to know which futures you will inhabit, not even a "god" can do that. Also, it is possible to set the quantum amplitude of certain futures to zero by the application of knowledge. — tom

This mode of discussion, smacks of the new religion of the materialist. One feels as though one is at an inquisition of sorts, questioning the almighty God of modern materialism. The 'which future' rejoinder leads one to a reductio absurdum and cannot be escaped, just as the almightly absurdity of God was medieval ne plus ultra of the dark ages.

"Which future" from this assertion one must conclude that within each of these futures there are also an infinity of futures and within each of those futures an infinity of futures... and here at last the materialist can cling to the the desperate notion of free will. The 'which future' is the rabbit hole down which an escape for the new God of self and free will might be effected.

Sorry, I don't buy it.

One Universe one past and one future. You can certainly have a multiplicity of Universes if one finds this notion pleasing, however the suggestion that this Universe (big bang to present) contains a multiplicity of futures would be contingent upon its possession of a multiplicity of pasts, which it does not
contain.

A single universe with a multiplicity of futures must also contain a multiplicity of pasts, an infinite number of such pasts each different. If there is such a thing as an objective real basis to this (our shared Universe) we cannot observe different pasts. We can only observe the past, a single history confined to our single shared Universe. One past might only be derived from one future. We do not know what the precise nature of the single future is and as such we might say or feel that it has infinite possibility, however the possibilities can only be assigned to the event components that we cannot as yet predict. Our inability to predict certain determined future forms of the universe does not lend the future any additional futures. One past is the consequence of one determined future. Multiverses and multiple futures are a veritable rabbit hole.

Why do we rush to hide down the rabbit hole when the temporal structure of our single and relevant Universe is so obvious?

M

QM is a fully deterministic theory. — tom

Agreed. So lets get on with the essential business of providing an intellectually valid Universal construct that combines the determined and atemporal nature of the Universe with the phenomenon of thought and avoid the self serving delusion of multiverses.

M