The fact that the world is 'imperfect' is actually a good motivator for spiritual practice, I think. — boundless

Just wanted to expand on this point. We instinctively want to be in a positive state and be from pain/suffering/unease. Also, we have a natural instinct of survival. And yet, our own nature contradicts those innate insticts. That, I believe, leads to a perception of 'unfairness' in this world, which can itself bring pain (and we, by instict, seek distractions from it...). So, I think that the awareness of the 'unfairness or imperfection of the world' doesn't come from reflexion but it is pre-reflexive*. We feel this unfairness, so to speak because our fragility and our being liable to death contrast our instinct.
I think that the religious 'seeking' of an escape/liberation/salvation is therefore ingrained in us.

So, yeah, I would say that the 'world as unfair' is a pre-reflexive awarenss which is rooted in our most central instincts. That's why, I think, the 'need of salvation/liberation' that is found in religions has been universal in all cultures. It can be elaborated upon in a religious doctrine or even seen as a paradoxical, delusional feeling that is maybe best to try to ignore in all possible ways. But it is IMO undeniably there and even if it is denied it remains in the background.
In fact, I believe that this feeling or this pre-reflexive awareness of the tragicality of our predicament is the main motivator for any kind of spiritual practice.

*I think that some 'spiritual' experiences are, indeed, experiences where there is a stronger-than-usual awareness of this paradox and this kind of experiences can IMO be the strong motivators for a 'drastic change' in both views and actions. I think that I had an experience of this sort in the summer of 2016 where I felt an anguished awareness of this paradoxical condition of living beings and I really felt it as something that indeed is of my concern. In my case, this experience caused a shift in views but not in actions.

Why not ground logic in its practical consequences? Like science. — apokrisis

Because, e.g. in order to establish if something is useful you need to have criteria to establish that it is useful, i.e. coherent with the concept of 'useful'.

Also, practical consequences are empirical facts.

That way entailment and causality might start to look like they have something in common. — apokrisis

I think that they do have something in common. In order to formulate the concept of 'causality', I think you need entailment as a prerequisite.

Thanks!

I'd like to address this again given that my previous response was just conjecture. What I want to point out is the ability for a system to change. This change is dictated by causality. To understand causality we have to regard nature as a unitary system evolving through time. So, with this said, what do you think "possibility" might mean? — Shawn

Well, I admit that I have some difficulties to answer to your question. First of all, I wasn't assuming that change is necessarily due to causality. Second, I was merely saying that we simply do not know if 'laws of nature' are contingent or not.

Anyway, I might define 'possibility' as a 'one state' in a collection of other possible state that 'something' might have.
So, a 'contingent entity' might be taken to mean that such an 'entity' can be either 'exist' or 'do not exist'.

The concept is so vaguely understandable only based on the way we perceive change itself. I don't really have an answer as to these deep "why" questions about what makes change possible. — Shawn

Well, I think that if we want to 'ground' logic then such answers must in some ways be answered.
I was trying to point out that 'grounding' logic on something else only seems to lead to some assumptions which are themselves 'ungrounded' and that, in fact, I think even stating those assumptions requires logic.

Modal logic is supposedly grounded by processism. I think that's the best answer I can give. — Shawn

Ok. Maybe you are right, but I think that even modal logic doesn't need such a 'grounding'

I was merely trying to point out that the concept on an 'unknown knower' doesn't necessarily entail a form of ontological idealism but it is, in my opinion, fully compatibile with some forms of epistemological idealism and some kind of phenomenology that does not make ontological commitments about the 'knower'. If I misunderstood you, I apologize for that.

And I wasn't trying to imply that you thought that the 'mind', 'subject' do not exist.

But anyway if you think that my questions were inappropriate I'll leave at that.

P.S. I do not consider myself an 'antirealist'. I do not deny the existence of a mind-independent reality (and actually I think that some kind of epistemic idealism or phenomenology are actually comptabile with realism). Not sure why you assumed that I'am an antirealist...

I'd like to point out that I view the very notion of having possibility within a system can only mean in terms of modal logic the necessity of determined states which are truth apt regarding causality. — Shawn

What do you thank that is the 'ground' of modal logic?

IMO: logic has no ground at all.

I hope this thread can go in such a direction. It seems plausible that the logic of causality can only be defined materially and temporarily. — Shawn

Let's concede that is indeed the case.

It seems to me that, according to you, we should infer logical principles by observing physical phenomena, which we assume that have regularities which can be 'translated faithfully' in a conceptual map.
Let's assume that it is indeed possible, in principle, to infer logical principles in this way.
But what does gaurantee us that, indeed, our inference is correct? On what grounds can we be sure that our inference is correct?

We cannot say 'further observations' because, after all, the problem remains the same.

So we now have two assumptions: (1) physical phenomena have regularities that can be 'faithfully translated' to conceptual maps/schemes and (2) we can know logical principles because we can have valid inferences based on observations made on the said physical phenomena

These two assumptions might be considered reasonable but... we have introduced the concept of 'inference', which is a type of logical operation which we actually want to ground in physical observations. This suggests to me that it is best to assume that logic is primitive.

I'd like to address this again given that my previous response was just conjecture. What I want to point out is the ability for a system to change. This change is dictated by causality. To understand causality we have to regard nature as a unitary system evolving through time. So, with this said, what do you think "possibility" might mean? — Shawn

I'll respond to this later!

Yeah, after all an 'experience' is something mental. So, in a sense, I can agree what is said.

But let's consider the structure of our experience. Experiences of course have contents, which might be called the 'objects of experiences'. But they all share a quality, a 'privateness', a 'sense' (for a lack of a better word) that they are experienced by 'me'.

Let's start by this: what is this 'me' according to you? does it ever appear as a particular content/object of experience? If so, when?

This "knower" (i.e. perceiver) Bishop Berkeley calls "God" which, not by coincidence I'm sure, is functionally indistinguishable from Gnomon's "Enformer". An infinite regress-of-the-gaps. :sparkle: :eyes: — 180 Proof

I disagree. It depends on how you interpret the 'subject of experience'. It might just be a formal property of experience. The subject never appears as an object of experience but this does not mean that it is non-existence or a substance that is independent from experience.

Thank you once again. I will bring it to bear on the topic of the OP. The basic point of my argument is that we do not really see 'what is'. We're unaware of our own sub- and unconcious machinations and as a result we project them onto 'the world', an inevitable consequence of our ego-centred individualist culture. That is the point of 'awareness training' and philosophy as a spiritual discipline, is the attainment of self knowledge. Much of what goes under the heading of philosophy nowadays comprises methods to rationalise the human condition, although what philosophy really should be doing is critiquing it. That is the context in which the question of the fairness or otherwise of 'the world' should be assessed. — Wayfarer

While I largely agree with you here, I think that we can still make correct judgement about the 'unfairness' of the world that actually help us to better our awareness of our 'sub- and unconscious machinations'.
For instance, if we consider, say, the 'unfairness' of diseases, the fact that this world actually does not match many of our idealisations - 'how we wish we it should be' - we arrive at a more disillusioned and mature view of both ourselves and the world itself.
The fact that the world is 'imperfect' is actually a good motivator for spiritual practice, I think.

I don't think we can have the cake and eat it too here. The way things seem is that the very notion of possibility within a system of physical laws gives rise to a logic that is modal. Modality might be a better term than contingent... — Shawn

I disagree. By 'contingent' I mean something that might to cease to exist/be valid. If physical laws are something contingent and they at some point change, the criteria by which we consider an explanation 'coherent' change, if we take them as the foundation of logic. I don't think that is acceptable.

It would be interesting to approach your question from the perspective of a counterfactual. What would a physics look like that could not be apprehended by any form of inferential or abductive reasoning? I don't think such questions are coherent, and there seems to be plenty of evidence attesting that everything in physics can be modeled. If it is indeed true that human logic can apprehend physics in a model or what have you (I think the right term, nowadays, is a "simulation"), then the circularity dissipates. — Shawn

Maybe physical theories, models etc cannot give us a picture of the 'physical world' but only useful tools to make predictions. If that is the case, it might be said that they work 'as if' they are a correct 'description'.

Consider, for instance, these two phrases:
"The sun moves from east to west and I predict that it reaches its maximum height at noon"
"When the bat hits the ball, (edit: it produces a force that) will cause an acceleration on the ball"

The first phrase is coherent, in many situations we can use it 'as if' it's correct, but it is nevertheless wrong if we take it literally: we know that the sun's movement is merely apparent. But for most practical situations I can certainly live 'as if' it's correct. I can take it seriously but not literally.
The second one is also coherent, for most practical purposes valid and yet we know that it cannot be taken as literally true.

You seem to assume that physical reality can be literally 'mapped' in a conceptual model, i.e. it has a structure that can be literally 'translated' in a conceptual framework. I guess that if we assume that this is true then maybe we might think that logic has a 'physical basis' (although then one might ask why this is so... but this is another story for another time).

On the other hand, physical theories might be able to work even if they cannot give a faithful picture of physical reality. But if this is true, then logic isn't really grounded in physics: the conceptual map is imputed by us and is not 'forced' by physical reality.

If a simulation were so accurate that it would be impossible to distinguish it from 'reality', it could be still possible that such a simulation would be correct for all practical purposes and not a literal picture of reality.

In brief, I think that your reasoning is based on a hidden assumption, i.e. that it is possible to build a conceptual 'map' of reality that is a literal picture of it.

I am sorry but I really don't understand what are you getting at.

To me logic is a discipline that aims at understanding the criteria according to which an explanation, argumentation, theory etc is coherent.
Physical theories, conjectures, protocols, predictions, explanations etc should be coherent.
Even, say, a false explanation must be coherent in order to be considered 'false'. In fact, in order to be a true 'explanation' must be coherent.
And I believe that the criteria according to which an explanation is deemed 'coherent' cannot be based on something that is or might be contingent.

To another poster you said earlier:

If physics is to be descriptive of logic, then, a "cause" would be defined by how the system of laws governing physics works, and from there to deduce what logic would be required to explain those laws in terms of decidability in logical space. — Shawn

This might be a starting point, I think, on which we can work.

IMO, the problem I see here is that when you try to describe the laws you might infer from your observations, you already use logic and mathematics (to make them coherent and give quantitative predictions). So, I guess I can say that in order to 'ground' logic in physics, you are already assuming that logic is fundamental.

What do you think about this last paragraph? Do you think I am wrong in detecting a circuarity here? If so, why?

Sure, I would like to highlight your uncertainty as stemming from not knowing how logical space can exist. Is it true in how I'm framing the ambiguity? — Shawn

No, as I said I don't understand why it is relevant to the debate about physics and logic, i.e. I see the two issues as separate, but I might be wrong.

there anything standing in the way of a direct relationship between logic and physics? — Shawn

IMO, all explanations relie on logical principles. But even, say, the basic concept of 'prediction' is based on logical reasoning:

"If [some kind of theoretical statements are valid] then [ I should observe such and such in a lab]"

So, I cannot see how physics can be considered as foundational to logic (or math) when the former cannot exist, in my opinion, without the latter. Note that even if all our physical theories, explanations etc were wrong their structure has logic as a prerequisite. Explanations and predictions are based on logic.

Also, logical argumentation cannot be based on physical phenomena and their regularities. Why? Because, there is no guarantee that physical phenomena and their regularities are not contingent and if they were contingent, then logical argumentation would not be compelling.

Unless one shows that regularities in phenomena are not contingent physics cannot be foundational for logic and mathematics IMO.

Yes, well may I ask whether there are things that cannot be modeled in a computer? — Shawn

Well, I don't know. I think that, say, some discoveries in physics could not be made by a computer (say e.g. Newton's discovery of gravitation)
But I am not sure why you think that it would show that if that is the case then physics would have a precedence over logic. After all, computer operations too follow logical principles.

I'm also trying to understand your argument about logic being transcendental. Do you mean to say logic is foundational to every state of change within a system, as logic seems necessary to produce change or "cause and effect" between objects that may have a relation as defined by physical laws through logic or the transcendental logic you mention. — Shawn

By saying 'x is transcendental for y' I mean that 'x' is a necessary prerequiste for 'y'. It's roughly like saying that a 'functioning visual system' (x) is 'transcendental' to 'seeing colors' ( y).

Anyway, what I meant is that logic is employed in any activity in physics, both theoretical and experimental.
Using your example, any causal explanation of physical phenomena must be formulated in a way that employs logical principles (this seems true even if Hume was actually right in his skepticism about causation. Causal explanation relie on logic, even those that are not valid).

I cannot conceive doing physics without employing logic. Not even experimental physics: after all, experimental protocols seem to be based in a procedure that follows logical laws.

On the other hand, I can study/do/discuss logic without any reference to physics. Same goes for mathematics, actually.

Is this chicken or egg? Physics came first in a non-anthropological manner. QED? — Shawn

You can study/employ/use logic without physics. But the viceversa is not true. You can't do physics without logic. That's why I said that logic is transcendental with respect to physics: it is a necessary precondition for physics. And same, I think, is true for science in general.

Ok I see :lol:

↪boundless Linde says it changes our perception of what appears to be ‘the past’. — Wayfarer

I think that it is a good way to put it :up: That's would be an 'epistemic' claim, consistent with epistemic interpretations. So, I don't think that is a controversial statement.

What's odd is that this is a thread about justice and fairness, yet it contains page after page of speculative quantum physics. — Banno

Lol, yeah, I see your point. Is it possible to 'split' the thread?

Indeed, physics has its merits. I don't think anybody denies that. I was just pointing out what some of its problems are, and how these problems relate to mathematical logic. — Tarskian

Ok, I see. Thanks for the clarification.

↪Wayfarer Again, there is the bit where you give and the bit where you take back. You want consciousness to be the special thing that collapse wave functions, but you don't want it to be different to the other stuff of the universe. — Banno

Actually QBism is a form of 'consciousness causes collapse' interpretation as I understand it. But given that in such an interpretation the wave-function is merely a tool that allows one to calculate probabilities to have some kind of experiences, I do not see how it can be problematic or how can it give a 'special' role to consciousness. It certainly does not mean that when a conscious agent makes an observation something in the 'fabric of the universe', so to speak, changes. The only thing that happens is an update of knowledge (in QBism this is expressed as an upddate of a probability, which in turn is interpreted as a quantification of a degree of belief).

I do not think that QBism or similar views are in contrast with your own view.

On the other hand, Rovelli's RQM holds that all physical objects can be considered as 'observers'. To be fair, I prefer QBism or similar views because, after all, what a 'physical object is' is extremely vague. Is a table a physical object? Are its legs physical objects? Does each atom of a table have its 'perspective'? Do all its atoms and the whole table have their own perspective? How they are related?
My problem with such a view is its vagueness.

↪boundless That’s pretty right - I do hold to a form of epistemic idealism. But I also claim that what we can claim is real is inextricably connected to what we can know, which I think is a consequence of my training in Buddhist philosophy. — Wayfarer

Ok :up: Note, however, that if one thinks that the delayed choice experiment shows that a measurement can change the past (rather than our knowledge of it), then one enters in some serious difficulties. That's why I don't like the expression 'partecipatory realism' even if respected physicists use it.

I do not doubt their credentials. I am merely saying that an ontological reading of certain ideas can be misleading. Of course it also depends on how 'ontology' is defined.

Yes, for instance QBism does require that 'observers' can 'experience', i.e. are conscious. But this does not imply that consciousness 'affects' the 'external reality' when a measurement, observation or anything like that is made.

If 'consciousness causes collapse' is taken as meaning that 'an experiment updates the knowledge/degree of beliefs' of a conscious agent, I do not see anything 'weird'. On the other hand, if it is taken as implying that an observation of a conscious agent changes the 'fabric of reality' or that 'consciousness causes a drastic change in external reality' and so on, then yes it becomes a problem IMO.

Thanks for the link, btw, I'll read it. Anyway, I do think that your own idealism is actually a form of epistemic idealism, rather than ontological (based on what I read in the past). Ontological idealism treats consciousness as the sole substance.

So like gauge invariance vs Poincaré invariance? Constrain spacetime to a manifold of points and it still has degrees of freedom in that the points may spin rather than sit still. They may be vector and chiral rather than scalar. Quantum spin arises as an intrinsic property and the rest of particle physics follows. — apokrisis

Well, maybe 'symmetries' are the only intrinsic properties that can be discovered by physics.

But even quantum spin after all is a quantity that describes how an object responds to an interaction. So I am not sure that it can be said that it is an intrinsic property of a particle (I admit that this does not 'conclusively' shows that it isn't lol...).

(IIRC there was a paper by philosopher Michel Bitbol that discussed this kind of things. If I find it I'll link or quote the relevant parts)

Yeah, that bit. The principles of physics are to be formulated so that the frame of reference being used does not change those principles. Any frame will do. This was intended to head off the common notion that science seeks a "view from nowhere" - perhaps the view you described and disagreed with as "independent from any reference frame". Rather, science seeks a view from anywhere. A pont worth making in a philosophy forum. — Banno

Completely in agreement with this :100:

That seems to be making 'an ontological claim'. Or wait - is it an 'epistemological claim?' — Wayfarer

It depends on the interpretation of this type of things. In epistemic interpretations like, say, QBism or some form of Copenaghen-ish interpretations, such an experiment results in an update of the knowledge of the agent/observer, not in the 'coming to be' of some kind of reality.
At best, it is an 'ontological claim' in the sense that 'the world' that the agent 'observed' is not 'the world in itself', but the 'world observed'.

These kind of theories do not make ontological commitments, i.e. do not attempt in describing 'how the world is in itself' (from a 'view form nowhere', if you like).

Unfortunately, concepts like 'participatory realism' IMO kind of muddy the waters. They seem to imply that 'the observer changes reality'. This in QBism, as I understand it, actually means 'the observer gets a new experience'. Other similar interpretations say that 'the observer knowledge its updated' and so on.

I guess that 'participatory realism' was developed in other to defend QBism and similar views from the charge of solipsism. But I do not really see the point of that. It only complicates the issue.

So, physicists want a "grand unified" pattern instead. Physicists seem to view this effort as essential. — Tarskian

My point was simply that I think 'Physics' as a discipline has still a 'raison d'etre' if 'a theory of everything' is impossible to achieve. I myself worked briefly in condensed matter physics, a branch of physics that is quite independent to the search of a 'theory of everything'. To some physicists might be essential, maybe even famous ones, but this does not mean that physics becomes vain if a 'theory of everything' is impossible. There still much to be discovered about physical phenomena that can be 'modeled' with current theories.

Hi Banno, apokrisis,

The Principle of Relativity asks us to set out the laws of physics in such a way that they apply to all frames of reference. — Banno

Correct. But this only says that physical laws are the same in all reference frames. Invariant properties in all reference frames are not necessarily property of a 'physical world independent of all reference frames'

Hence this suggests to me that any true description of the physical world can be made from any perspective/frame of reference. — Banno

I disagree, if the 'phyisical world' here is meant the 'physical world as it is independent from any reference frame'. On the other hand, yes, I agree if this is taken to mean that any reference frame can be used to discover/find some truth that is valid for all other reference frames.

But we can have a theory of reference frames can’t we? We continue on as we see with holography, de Sitter metrics, or twistor space. We can have general arguments that pick out 3-space as special as the only dimensionality that has the same number of rotational degrees of freedom as translational ones. — apokrisis

Yeah, I guess that we can but I am not sure how this is an objection to what I said earlier, if you meant that way. I am perfectly fine, for instance, with what you say about 3-space. But this can be IMO understood as a pointer to a property in common to all reference frames. Regardin holography, de Sitter ant twistors, well as I said, they all seem all quite far as the 'physical world as it appears to us', so to speak. As I said:

'How the world is' independently from any perspective seems to get weirder and weirder as we get to more 'advanced' theories. — boundless

I see it as a sort of 'evidence' for this kind of tendency.

There may always be questions but they also can be new ones. — apokrisis

Agreed.

Anyway, to put in another way what I am saying, I think that a distinction can be made between 'intrinsic' and 'relational' properties. Relational properties are not properties of 'a thing in itself' so to speak, but is a property that arises in a relation. As an example, the apparent height of a tower seen from a distance is a relational property, not an intrinsic one (it cannot be assigned to the tower, without taking into consideration something else). If we do not know intrinsic properties of objects we do not know them 'in themselves', but only in relation.

According to, say, Galileo all 'primary' qualities were intrinsic to physical objects. But his own 'principle of relativity' actually showed that velocity is a relational property. In special relativity, for instance, even distances and temporal durations are not intrinsic properties*. In QM this 'relationality' is even more explicit.

*Yeah, the speed of light is the same in all inertial frames in special relativity. But it does not follow that it is an intrinsic property: after all, velocity is a concept that makes sense only when a particular reference frame is considered. I think that the same can be said even for rest mass. Rest mass is a quantity that tells us how an object 'responds' to some interactions. BTW, after all the operational definition of all physical quantities is in fact relational. So, maybe it might not be surprising if it turns out that they are not intrinsic.

It is actually the ultimate goal of science: — Tarskian

I disagree. Science can exist even if such a theory is impossible. It isn't essential to science IMO, so it cannot be its 'ultimate' goal.

One of those possibly pseudo-questions which may be sophistry; but, in your opinion do you think physics describes logic? — Shawn

No. In fact, one might say that the opposite is true. As Hume said, there is no 'proof' of, say, physical causality, we cannot be certain of it. On the other hand, it seems that any physical theory must be logically consistent. Logic is, I think, transcendental (i.e. a necessary precondition to any explanation) as the early Wittgenstein said.

Also, there is no conclusive evidence that physical laws are not contingent.

Doesn’t the same problem crop up in a relativistic context such as the simultaneity issue? No absolute reference frame and yet that can still be approached in the limit. — apokrisis

I agree with that. In fact, I believe that relativity has similar interpretative difficulties. On one hand, a 'literal' interpretation of relativity leads one to an 'eternalist block view', i.e. change and the 'now' are merely illusions. On the other hand, as Einstein himself said the 'now' is a great problem for relativity. After all, the experience of the 'now' is undeniable and so 'immediate' experience seems to contradict a literal interpretation of relativity. So what?

In relativity the 'branching' of space-time into space and time is associated to the choice of a particular reference frame, i.e. perspective. This is similar to what happens in QM with 'observers' (whatever one takes them to be): only at measurement/observation/interaction etc physical quantities assume a definite value. But hey, even in classical mechanics velocities etc have undefined value until a reference frame is chosen.

Like QM and like what I said about newtonian mechanics, this suggests to me that any description of the world must be made from a particular perspective/frame of reference. 'How the world is' independently from any perspective seems to get weirder and weirder as we get to more 'advanced' theories.

In a sense, I get that it can be seen as a disappointing view but, on the other hand, it is at the same time in a sense 'liberating' and 'awe insipring' (reality seems much more mysterious than it appears to be...).

I think that my view is close to the view presented by Bernard d'Espagnat in his 'On Physics and Philosophy' or of the late David Bohm (who wasn't an 'instrumentalist'). For the latter see e.g. this interview*: https://www.youtube.com/watch?v=Mst3fOl5vH0 (yeah, I know that the late Bohm is controversial but still...also his concept of 'active information' might be congenial to biophysics)

Yes. It is perfectly acceptable to me to go full Copenhagen and say all we can know is the numbers we read off dials. If a proper ontic interpretation isn’t available, quantum physics still works as instrumentalism. Copenhagen remains the sensible backstop epistemic position. — apokrisis

Same as all theories. It does not matter that the literal interpretation of newtonian physics is right for its applications.

IMO Physics seems to assume that there are regularities in phenomena (but any ontological commitment of the theory is unneeded)

Yeah. Heard quite a bit from him on Physics Forum some years back. But I can’t remember whether I was agreeing or disagreeing with him at the time. I will have to check that reference. :up: — apokrisis

Lol, I 'knew' him there too years back. Seems to be a very thoughtful researcher. Unfortunately I found many of his works very complicated and well above my level. I do not know if his interpretation is actually accepted as a 'canonical' one as say de Broglie-Bohm, MWI, Copenaghen etc

*I do not think that he is completely correct in that interview, but I agree with his main message.

Classicality comes to be in the limit. So reality never arrives at that ideal conception we have of it, but through decoherence, it approaches a classical state for all practical purposes. We can apply that brand of physics and logic to it. — apokrisis

Ok, I see. But IMO, while decoherence - for all practical purposes - explains why we see definite outcomes in experiments, it doesn't explain why experiments have a unique outcome. In other words, as far as I can tell, this is why decoherence is not taken as a complete solution of the measurement paradox. Decoherence gives the definiteness of the observed outcome but is not enough to explain the uniqueness of the outcome.

But the cat is a hot body in a warm place. It went into the box decohered and not coherent. It wasn't converted to a Bose condensate. It remained always in a "thermalised to classicality state". — apokrisis

OK, you are right.

MWI is the kind of nonsense to be avoided. Spontaneous collapse fails if you demand that reality actually be classical rather than just decohered towards its concrete limit. Zeilinger's information principle captures some aspects nicely. — apokrisis

Ok, sorry for the misunderstanding then. I fully agree with you about MWI. I referred to spontaneuous collapse theories because they provide a consistent 'ontologically interpretable' (or 'realist') explanation for the uniqueness of the outcomes.

But, anyway, I concede that, in a sense, one can say that decoherence is 'enough': after all, it is enough to explain, for all practical purposes, why we get definite outcomes. As far as observations, applications, and practical concerns are concerned, yeah, you don't need other assumptions. Still, from a theoretical point of view, I think that uniqueness of the outcomes is a crucial assumption in physics and I do not see how decoherence can explain that.

To be honest, I set the interpretation aside these last few years to let the dust settle. Youngsters like Emily Adlam are coming along and making more sense. — apokrisis

Ok, I see! I don't know Adlam, thanks for the reference.

In a sense I think I agree with you. IMO, I see QM as a practical recipe, useful for predictions and applications. I favor epistemic interpretations like QBism. I think that it is impossible to make a literal interpretation of the 'orthodox' quantum formalism that makes 'fully' sense, so to speak.

But as I say, biophysics puts it all in a new light. Something has been missing. It seems obvious to me that this is it. — apokrisis

Ok, I see, thank you.

Personally, I think that QM strongly suggest that we cannot describe physical reality as it is independently from a particular perspective and that physical theories are, in general, useful tools and 'fictions' (but as I said in my previous post, I think that this insight is actually present even in newtonian physics, albeit less explicitly). But this certainly does not mean that, in the future, it won't be replaced by something better.

P.S. I have a hunch that you might find interesting the Thermal interpretation by Arnold Neumaier. It is an 'ontologically interpretable' interpretation which apparently solves the measurement problem and other issues of other 'realist' interpretations (btw, it is also holistic: it sees entangled particles as a single extended objects, not reducible to its parts that have nonlocal properties...so some 'quantum weirdness' remain). Unfortunately, his papers are too difficult for me

Regarding the 'parallel' idealism-realism debate, I think that physics - and science in general - is, well, silent on that issue as well.

For instance, the concept of 'reference frames' is central to the theory. In fact, many physical quantities have undefined values before a reference frame is specified, i.e. this means that they are not intrinsic properties of physical objects but only relational ones. Reference frames are associated to physical objects but are actually abstract concepts of the theory - they more or less correspond to 'perspectives' where a given object is at rest. And all measurements happen in a given frame of references.


Anyway, even in classical, newtonian, mechanics the 'physical world as it is, independent from any perspective' is quite different from 'the observed reality', which is always associated to a given frame of reference.

Related to the above, I would ask: what constitues a 'perspective'/'reference frames' in physics?
And how is the physical world independent of all perspectives? Can we describe it?

Nope. Enzymes are large mechanical structures. Decohered and classical for all intents and purposes. But they can dip their toe into the quantum realm, exploiting tunneling to jump chemical thresholds. — apokrisis

Hi, I read your linked post and I enjoyed it. But still I don't understand how 'classicality' 'comes to be' in your view.

Let's consider a less crude version of the Schrodinger's cat experiment, where the cat is either awake or asleep. Decoherence IMO can only remove interference, not superposition, hence the cat is still, if we take the quantum formalism literally, awake and asleep at the same time. However, decoherence gives the appearance of classicality because it says that it is observed in a definite state.

Let's say that I observe the 'asleep' cat. In your view, what happened to the 'awake' cat?

In MWI, the superposition is always preserverd and each definite state is 'actualized' in a branch of the wavefunction (but observers have access only to one). The 'branching' can be seen as due to decoherence.
In epistemic Copenaghen-ish views, QM is not to be interpreted literally and the collapse is just an update of knowledge (these views do not make any ontological commitments to what 'happens' before the observation: the state of the 'unobserved' cat is beyond the range of descriptions).
In (non-local) hidden variables interpretations, the cat is always in an unique state and it is determined by these hidden variables
In spontanueos collapse theories (these are actually not interpretations as they make different predictions from QM), at a certain scale wave-functions collapse and give an unique definite outcome
In RQM, anything can be an observer and any interaction is a measurement. But, again, like in epistemic views the 'unobserved' cat is in an indefinite state.
And so on.

Spontaneous collapse theories - (Edit: or maybe some version of MWI) - IMO seem to me the most compatible to your views.

I make this same point all the time. :up: — apokrisis

:up: Glad to hear that! I think that, what is common to all physical theories is that they are predictive tools with an extraordinary range of practical applications. Physics per se does not give us any ontology IMO. I also think that many debates about topics like free will, reductionism* etc are due to an unneeded ontological interpretation of physical theories. In fact, I think that the most consistent form of 'realism' with all physical theories is actually what Bernard d'Espagnat called 'open realism' in his "On Physics and Philosophy" (p.28, emphasis in the original):

Realism (Open). This is - indeed quite 'open' - view that there is something the existence of which does not hinge on thought
Is this 'something' the set of all objects, of all the atoms, of events, God, the Platonic Ideas, still something else? Open realism is mute on this.
...
It just says 'something,' in the widest possible sense of the world.

Of course this does not mean that is the only viable form of realism.

*I do believe, in fact, that even newtonian mechanics is not really 'reductionistic'. Conservation laws seems to me properties of a whole isolated system, not reducible to the properties of its parts. Of course, if one does not make any ontological commitments, newtonian mechanics is neither reductionistic nor holistic.

I posted this general story here - https://thephilosophyforum.com/discussion/comment/679203 — apokrisis

Thanks for the link. I'll ask more questions after reading it :)

What you often hear from idealists (Kastrup and Hoffman are good examples) is that materialism and a physical world is debunked and quantum physics tells us reality comes into being by the act of observation. Therefore idealism is a more reasonable and parsimonious explanation for our experience. I've often thought that the arguments in favour for idealism are actually more arguments against old school materialism than any great championing of an 'it's all consciousness' style metaphysics. — Tom Storm

Note, however that Hoffman does not really say that. He says, more or less that QM suggests that 'physical reality as it appears to us' comes into being by the act of observation. And he says that this is consistent with his 'interface theory of perception', i.e. the view that perception gives us a simplified interface of the 'external reality' which is useful for our survival.

Unfortunately, this is then mixed up with his 'conscious realism', i.e. his Berkeleyan-like view that conscious agents are the only reality. To his credit, he never say that the 'interface theory of perception'necessarily implies 'conscious realism'.

Note that his 'interface theory of perception' is a kind of epistemological idealism (which is actually compatible with the existence of a mind-independent reality). His 'conscious realism' is of course a form of ontological idealism. Unfortunately, sometimes his two theses are mixed up.

Hi apokrisis, all,

I have outlined many times how biosemiosis now adds the epistemic cut to the business of quantum interpretation. As a mechanism, a modelling relation, even our enzymes and respiratory chains are actually doing that - preparing states of coherence with the intention of collapsing them and so ratcheting the entropy flows of a Cosmos guided by the telos of the newly NASA-rediscovered concept of dissipative structure. — apokrisis

I think that the problem of this view is that it does not explain how those 'complex' objects/processes like 'enzymes' or 'respiratory chains' arose in the first place. Was everything in superposition back then? What happens when these kind of object 'cause' a collapse?

I think that all positions of what consitutes an 'observer' are susceptible to this kind of objection and it is a serious objection if QM is interpreted ontologically. I think that it is best to interpret it epistemically: wave-function, Born Rule etc are all useful concepts, computing techniques etc that enable us to make correct predictions. In this view the 'collapse' is just an update of knowledge and QM is silent about what 'happened' before the appearances of 'observers' (and it is also silent on what constitutes an 'observer'). QM is IMO best seen as a theory that does not make any ontological commitments: it does not give a 'picture' of 'how reality is'* and it does not say to us what an 'observer' is but is still very useful to make predictions, applications and so on. (My favorite interpretation is QBism, althought I think that, unfortunately sometimes its proponents seem to present it as an ontological interpretation of QM, perhaps unwittingly... especially when they talk about 'participatory realism')

As an aside, I do not think that 'decoherence' alone is enough to solve the measurement problem. It does explain (at least 'for all practical purposes') an appearance of a classical world, but it does not IMO explain why we observe a single outcome in quantum experiments (MWI supporters like decoherence because it explains why 'branches' of the wave-function separate. But MWI makes the additional assumption that all outcomes are actually observed even if they are inaccessible to us)

*I actually think that we tend to do that also in classical physics. For instance, an ontological interpretation of the concept of 'force' in newtonian mechanics is clearly inappropriate but it is an useful conceptual fiction that helps us to make predictions, build things etc (like, say, the concept of 'sunrise' or 'sunset'). The same IMO holds for QM.

https://erlichdallc.wordpress.com/2019/04/11/my-current-understanding-in-a-nutshell-of-everetts-relative-state-formulation-of-qm/ — i aM

Nice!

Isn't a core idea of SR "relativity of simultaneity", i.e. simultaneity of events is entirely dependent on the reference frame of the observer? — i aM

I believe that it depends on how you define SR. In the usual definition, both preferred foliation of spacetime and retro-causality are incompatible with SR.

Yet, I think that they are both compatible with Lorentz symmetry.

By my understanding, in PWT the pilot wave controls the velocity of the particle. And that velocity depends not only on the position of the particle, but also the positions of all the particles it is entangled with; and that information is all available instantaneously to the pilot wave which controls the velocity of the particle. I don't see how that can be reconciled with SR. — i aM

Well, there have been attempts to reconcile SR and PWT. To my knowledge, they involve the use of preferred foliations of space-time or retro-causality. Of course, this is different from saying that PWT can be reconciled with SR in its standard formulation, but the point is that apparently it can be reconciled with Lorentz symmetry.

I was however referring to this way of reconciling SR and PWT via this defense of presentism proposed by NoAxioms:

I have done an advocatus diaboli thread defending the compatibility of relativity and presentism, so I maintain that they're not incompatible. SR says that the preferred frame cannot be determined given the special case after which it is named. But inability to detect such a frame does not mean that there isn't a special one. Presentism doesn't even require it to be a inertial frame, and no presentist that knows their physics seems to assert that it corresponds to such a frame. The foliation is always bent, which has the interesting paradoxical implication that no two stationary observers are simultaneous in each other's inertial frames. I find that hilarious, but not paradoxical. — noAxioms

Yes. With locality, which is essentially saying no FTL. — noAxioms

Ok! Fine, then we agree :smile:

Pilot wave is a form of Bohmian mechanics: Pro counterfactual definiteness (objective state) and denial of locality. So I wonder how they interpret spooky action at a distance using pilot waves. I don't know the official line on that. They certainly cannot reproduce spooky action using a classic pilot wave setup like they use for double slit. — noAxioms

Considering that the 'wave-function' is a 3N-dimensional (N being the number of particles) object and the theory predicts that the 'influence' is instantaneous, I do not think that there can be an explanatory dynamical model like - say - the one that uses mediators.

(As an aside, I prefer using the term 'de Broglie-Bohm theory' or 'pilot-wave theory' for various reasons. Among these, 'Bohmian mechanics' is actually the preferred term of a specific sub-school of the dBB-supporters and also downplays the role of de Broglie. It gained success and maybe it is the most used term in literature... :smile: YMMV )

I simply meant that without the selection postulate, it seems that RQM implies the splitting.

Anyway, I agree with you. RQM seems simply silent on this point. — boundless

Maybe it's embarrassed. :yikes: — Wayfarer

Well, possibly! :razz: — boundless

This is why I resist describing RQM under presentist terms. If time is external to the structure that is the universe, then such selection is an objective act relative to this realm under which time exists, and it isn't really RQM anymore if such an objective action takes place.

With time being part of the structure, no event/state (something to which a relation can be made) 'flows' to a different event, necessitating such a selection. Thus there is no selection postulate.
This isn't an embarrassment, just an implication of a relative interpretation. — noAxioms

Ok, I can see the problem! Even the presentism you referred before as compatible with SR seems to imply a unique, well-defined state of the universe (the 'unicity' referred in the SEP article on Consistent Histories) :smile:

(as I said it was not exactly what I had in mind. But I think I'll leave it at least for now...)

The Andromeda Paradox is about the ambiguity of what time it is elsewhere, not about the state being definite. The former is a frame dependent thing and the latter is a statement of superposition of something unmeasured. I think you meant the former but your wording suggested the latter. — noAxioms

Yeah, sorry!

Totally agree. Two observers at the same place but different frames might disagree about what is going on at Andromeda, but they'll agree entirely about what has been measured. The light cone from that location is a frame independent thing. — NoAxioms

Yes! In Relativity the ordering of events in every light cone is an invariant (unless one accepts tachyons or any FTL influence). — boundless

I didn't say that. I said the set of events in a given light cone is frame independent. The ordering of those events is still quite frame dependent. — noAxioms

I am not sure I am following you. In fact, I just am saying that the cause precedes the effect in all reference frames without FTL. Isn't it right? :smile:

Interesting corollary for a presentist, who by definition cannot observe any existing thing. In 8 minutes, the thing I observe will not be the present state of the sun. It will be an observation of something nonexistent.
— noAxioms

Yep! Presentism is somewhat problematic in Relativity. I would say that 'global presentism' is simply incompatible with relativity of simultaneity. Maybe a form of 'local presentism' can be saved but it is surely counter-intuitive (I personally lean towards some form of presentism and I admit that I am troubled by this). — boundless

I have done an advocatus diaboli thread defending the compatibility of relativity and presentism, so I maintain that they're not incompatible. SR says that the preferred frame cannot be determined given the special case after which it is named. But inability to detect such a frame does not mean that there isn't a special one. Presentism doesn't even require it to be a inertial frame, and no presentist that knows their physics seems to assert that it corresponds to such a frame. The foliation is always bent, which has the interesting paradoxical implication that no two stationary observers are simultaneous in each other's inertial frames. I find that hilarious, but not paradoxical. — noAxioms

Ok, I see. Interesting, thanks! I wonder if this can be used to reconcile SR with pilot-wave theory... :smile:

Note, however, that the 'presentism' that I had in mind was somehow different. I am not sure of how to explain it - so, I'll leave it for now.

As he puts it, decoherence gives us quasi-classical worlds (branches) but not actual classical worlds. Which means that decoherence can be treated as irreversible and the worlds as classical for all practical purposes. Nonetheless interference between branches continues to happen in accordance with quantum mechanics. — Andrew M

Ok, I see!

I think splitting might be implied only because Copenhagen and Consistent Histories don't specify any physical mechanism, whereas MWI does. But since some other unknown physical mechanism can't be ruled out at this point, then being silent seems a reasonable option (and treating interference as unactualized potential). — Andrew M

Well, yeah, this would explain the silence :smile:

Another curiosity: what do you think about the problem of interfering branches in MWI (and maybe in RQM if no selection mechanism is accepted)? As 'I aM' (see here) noted it is true that due to the decoherence the interference term becomes very small. Yet, rigorously, it is not exactly 'zero'. Given the fact that decoherence occurs a lot of times, it seems possible that - sooner or later - interference will be observed. In other words, it seems that decoherence gives (multiple but) definite outcomes only 'for all practical purposes' (I remember to have read that decoherence is said to solve the measurement problem 'only for all practical purposes' but I am not sure that this the reason why it is said so...).

Nit-pick: you think that maths, a human invention, is more fundamental than the stuff of which the universe is built?
— Pattern-chaser
I consider it something discovered, not invented. If invented, pi would not be the same value in another world.
— noAxioms

:up: — Wayfarer

+ 1 :wink:

(More precisely, I believe that there is something in maths that is discovered. It cannot be totally invented)

I simply meant that without the selection postulate, it seems that RQM implies the splitting.

Anyway, I agree with you. RQM seems simply silent on this point.
— boundless

Maybe it's embarrassed. :yikes: — Wayfarer

Well, possibly! :razz: