Math doesn't do anything observable. It's a tool of measurement. Quantum mechanics is math. Quantum mechanics is understood if someone understands the formulas, principles, and rules of doing it. The results of different experiments began a race to explanation. Hence, the different 'interpretations', all of philosophy, not science. All three of the most popular'interpretations' employ the normal everyday notion of causality and differ only insofar as they set out different consequences from different assumptions about the same experimental results.

The results were witnessed.

The results were witnessed. — creativesoul

I'm still none the clearer about the distinction you wish to uphold.

What you said was....

We did not arrive at causality by virtue of inventing and/or imagining it. We arrived at causality by virtue of witnessing it happen... over and over and over again... — creativesoul

And my reply is that we did invent a classical model of causality. And now a quantum model would challenge its predictions. We expect to witness a different statistics. And indeed we do, time and again.

I take it for granted that inventing a model and testing that model are two aspects of the one intellectual enterprise.

And then from the point of view of the scientifically-informed philosopher, one would be dubious about any "commonsense" claims that we instead just look out and see the world as it actually is. Any such folk theory of causality is only going to be an unthinking acceptance of the "evidence" of a history of classical physics and the logical tropes it has fostered.

So what are you trying to say? That our belief in classical causality is just some kind of direct "witnessed" knowledge and not instead a socially constructed belief (albeit a belief that "really works").

Or do you have a different point? I can't follow what you might want to say.

Math doesn't do anything observable...The results of different experiments began a race to explanation. — creativesoul

Which uses maths to account for anomalous observations. The whole history of physics is littered with them. SO maths makes predictions which then either account for, or fails to account for, the observation. So it is deeply intertwined with observation. The interpretations of the meaning of quantum mechanics are a completely different matter and really outside science per se.

It's much more than just asserting a novel distinction, although I am prone to do just that. This is a bit different...

To conclude that quantum mechanics operates on a more fundamental level is very questionable. It becomes apparent that that is gravely mistaken if and/or when we continue on to say that randomness is fundamental in it's relationship with causality. Quantum mechanics cannot effectively exhaust cause and effect. That's not a feature. It's a flaw.

That alone is adequate reason to deny placing much value upon the idea that quantum mechanics id somehow fundamental to classical mechanics.

If it were the case that randomness is more fundamental then we would need to ignore overwhelming fractal evidence to the contrary in order to sincerely assert this. Fractals are patterns. Pattern cannot happen without sequences of events. Sequence cannot happen without predictable time increments. Pure randomness has no predictable sequence. Randomness falls well short of the mark. It cannot produce what we do witness.

Yup. Not sure about my memory, but it seems to me that some of our very first conversations were on this topic. Do you recall?

Which uses maths to account for anomalous observations... — Wayfarer

Here's my take...

When observable entities are smaller than a planck length and the act of observing them includes shining light on them then the observation itself begins a causal chain of events as a result of the mass of the photon influencing the path(location) and movement speed(acceleration) of the subatomic particle being observed.

Hence... The Uncertainty Principle.

There's nothing random about it.

The superposition of states is rubbish. It does not follow from the fact that an electron is always found within a predictable range of probable locations that it is everywhere it can be at the same time.

Quantum Entanglement intrigues me though...

Hi. What do you mean by retro-causality?

Please explain.

As far as I know, retrocausality isn't ''possible''. Perhaps I'm stuck with the classical causal definition where reverse causation needs to be specifically ruled out and that we do by checking order of events in time.

To make sense of retrocausality we need to redefine causation. What is this definition? Pray tell.

To conclude that quantum mechanics operates on a more fundamental level is very questionable. It becomes apparent that that is gravely mistaken if and/or when we continue on to say that randomness is fundamental in it's relationship with causality. — creativesoul

It is a witnessed fact that the quantum account beats the classical one in terms of its predictive accuracy. I think it is only you who find it questionable that it ain't more foundational.

Though if you followed my own position, I am indeed arguing it isn't "foundational" in the conventional sense. It is indeed a less constrained picture of reality. My ontology is boot-strapping. So I am taking the conversation in quite a different direction there.

Then as to randomness, again a boot-strapping metaphysics expects a stable ontology to arise out of dynamical contrasts. So it is not that randomness is fundamental. Randomness is simply the dialectical complement to its "other" of deterministic constraint. You have two polar tendencies which together give rise to the third emergent thing of a structured reality - one which has the stability of a statistical system.

It is only because constraint is a thing that freedom is also a thing. So the more constrained a system, the more definite or fixed its freedoms. You can count the probability of a coin toss because you know that the coin can only either land heads or tails. Flip a quantum coin (or more accurately, a pair of them - the equivalent of two particles with spins) and the statistics are different because there is a loss of information due to the entanglement of the outcomes.

So perfect randomness can't exist by itself. It needs a matching degree of absolute constraint to define it as being a counterfactually definite possibility. If there are only two answers on offer - heads and tails - then a game of perfect chance becomes possible.

If it were the case that randomness is more fundamental then we would need to ignore overwhelming fractal evidence to the contrary in order to sincerely assert this. Fractals are patterns. Pattern cannot happen without sequences of events. Sequence cannot happen without predictable time increments. — creativesoul

Fractals are a bad example for supporting your case because they in fact show that behind ordinary "classical" probability spaces - the kind described by a Gaussian bell curve - there is now the less constrained probability spaces of scale-free systems.

It is just like how QM was found hiding behind classical physics, and imaginary numbers behind real numbers. If you relax a major dimensional constraint, you still get organised structure. And now an actual mathematical structure that does a better job of accounting for nature "in the raw".

So fractals are the mathematical story of many natural random processes - especially dissipative thermodynamical ones, such as river branching and coastline erosion, because the spatiotemporal scale drops out of the physical picture as a constraint on the expression of randomness or spontaneity.

Deterministic chaos and fractals were a big deal because they revealed that chaotic nature was in fact predictably random even though any constraints were as minimal as could be imagined. So they speak to nature that has the simplest possible balance of chance and necessity. Gaussian systems are by contrast far more artificial in being overly-constrained (by the Universe's own foundational standards).

Pure randomness has no predictable sequence. Randomness falls well short of the mark. It cannot produce what we do witness. — creativesoul

Pure randomness is pure vagueness. There couldn't even be a sequence to judge.

As I say, chaos theory was a big deal as it gave a mathematical understanding of what a minimal state of constraint looks like, and thus what a maximal state of randomness looks like. You had to have both to have either. Each becomes the effect of the other's cause.

It is this contextual mutuality that is a big part of the conceptual shift towards a holistic ontology here. QM showed that we have to take complementarity seriously. Chaos theory said the same thing.

Here's my take...

When observable entities are smaller than a planck length and the act of observing them includes shining light on them then the observation itself begins a causal chain of events as a result of the mass of the photon influencing the path(location) and movement speed(acceleration) of the subatomic particle being observed. — creativesoul

That's one familiar pop science explanation. But why does the Planck scale create a sharp cut-off long before location or momentum are driven towards infinity?

Sure, the maths says things start to bend off sideways as you approach the Planck limit. Your effort to measure a system becomes so strenuous that at some point it produces such an energy density that the whole region of spacetime is going to collapse into a black hole.

But that is long before you approach infinite efforts. So you haven't actually explained anything about the causality of what is going on. You don't have the kind of holistic/contextual story that quantum gravity is seeking to establish.

As far as I know, retrocausality isn't ''possible''. — TheMadFool

Look up Cramer's transactional interpretation or the Wheeler/Feynman absorber theory.

But I tried to make clear that I am talking about retrocausality only in terms of backwards-acting constraints on probabilities. The future can determine the past to the extent that future experimental choices will limit the statistics of some past process. So the future doesn't produce the event in a determining fashion. It just affects the shape of the probability that existed back then.

The classic experiment is the quantum eraser. I can decide whether to measure an event as either a single slit or two slit situation. And even after the particle has passed through the slits - by a normal temporal view - I can make that decision and still see either kind of statistics.

So normal causality says that is impossible. The difference couldn't be imposed on nature after the fact. But in quantum theory, it is routine. Systems can be entangled across time.

The data revealed the existence of quantum correlations between ‘temporally nonlocal’ photons 1 and 4. That is, entanglement can occur across two quantum systems that never coexisted.

What on Earth can this mean? Prima facie, it seems as troubling as saying that the polarity of starlight in the far-distant past – say, greater than twice Earth’s lifetime – nevertheless influenced the polarity of starlight falling through your amateur telescope this winter. Even more bizarrely: maybe it implies that the measurements carried out by your eye upon starlight falling through your telescope this winter somehow dictated the polarity of photons more than 9 billion years old.

https://aeon.co/ideas/you-thought-quantum-mechanics-was-weird-check-out-entangled-time

A model of our invention is not something that causality can be.

I would warn here against conflating a report(conception if you prefer) of something with that something. The two are not always the same thing. Sometimes they're virtually indistinct. Sometimes that something exists in it's entirety prior to our very first report of and/or on it.

Causality is one such thing. Quantum mechanics is not.

Your effort to measure a system becomes so strenuous that at some point it produces such an energy density that the whole region of spacetime is going to collapse into a black hole. — apokrisis

:rofl:

Fractals are prior to any mathematical story.

...especially dissipative thermodynamical ones, such as river branching and coastline erosion... — apokrisis

Yeah.

There's an interesting correlation...

:smirk:

Quantum mechanics is math. Math is language. Quantum mechanics is the language used as a means to describe specific observational results. Quantum mechanics is existentially dependent upon simpler maths.

Causality is not.

For all these reasons and more, I think it is utter nonsense to talk about effects/influences happening before their cause.

Probability presupposes causality. It is nothing more than a mathematical description borne of our ignorance regarding all of the different influences in the causal chain of events.

This causal chain of events, though, is not linear but more-so a tree, but even less so a tree than it is a forest. So you can see where causality breaks down. It does so as it is looked upon as linear, to the causa prima.

It is much more interesting when when does not gape at it as 'causality tied to a long past post', but, on the contrary, when one apprehends it in its ambiguity, its continuity, its part of a continuum, and lastly, in its complexity-- showing us not the contingency of the world but its massive multidimensionality and metaphors.

But I tried to make clear that I am talking about retrocausality only in terms of backwards-acting constraints on probabilities. The future can determine the past to the extent that future experimental choices will limit the statistics of some past process. So the future doesn't produce the event in a determining fashion. It just affects the shape of the probability that existed back then. — apokrisis

This I get. Thanks. Am I correct in inferring that the definition of causation in quantum physics has been modified a bit from its classical form?

I was thinking about cyclical time but that doesn't make sense because time is defined in terms of physical change e.g. the swing of a pendulum or the vibration of an atom.

Since vibration is repetition between two states I was wondering if in a world where events swing between two or more states and nothing else it would be impossible to distinguish the temporal sequence of events and we'd be unable to distinguish cause and effect or, worse still, everything would be both cause and effect.

In your own little world on this one.

Yes. QM means no local realism. As a matter of interpretation, you can then explain that in various ways.

On circularity, there is obviously plenty of speculation about wormholes and what they would do to causality - https://www.iflscience.com/physics/wormholes-could-solve-a-key-problem-with-quantum-mechanics/

:smile: :up:

If QM can undermine causality, then how can physicists actually say that they did an experiment (the cause) that made them think differently about causation? How do scientific experiments work if not by causation? How is it that QM allows scientists to make predictions if there is no causal order? It seems that their claims undermine their own experiments.

All cause exists through effect with effect being an approximation of the original cause under a perceived separation through the multiplicity of it.

Further more all effect is a cause in itself, and what can be observed is that the cause exist fundamentally through the effect.

Under these terms we observe cause and effect fundamentally as the mirroring of structure equivalent to a form of replication of limits which occurs as a form of symmetry (or similarity conducive to a binding median) where the cause/effect linear chain (which can be dually observed in circular terms, with this dual circular and linear nature observing all causality existing through a form of self-reflection where any perceived multiplicity is merely an inversion of unity into multiplicity through 0 dimensionality.

This infinite replication of limit effectively observes all cause as non-movement as infinite change is non-movement itself. All change is the observation of multiplicity where the observation of cause is effectively the observation of a self-reflective structure considering what "was" is determined effectively by what it "will be" and the future inevitably determines the past as an extension of the past through itself.

What is change, as one structure relative to another, effectively is an observation of multiplicity where one reality effectively exists as a part of and composed of other parts which observe change as a boundary of movements giving premise to proportionality or the "ratio" as change through relation itself.

This change of part through part, observed mathematically through the fraction as both an observation of division and multiplication through "times" as a means of localizing a reality into parts, effectively is an observation of inversion of unity into multiplicity where all 0d dimensionality, or absence of structure, acts as a focal point of inversion and is not a thing in itself.

A model of our invention is not something that causality can be.

I would warn here against conflating a report(conception if you prefer) of something with that something. — creativesoul

Yep, so you are making some confused epistemic point about our models of reality.

Now of course we can presume that reality exists as whatever it is, independent of our thoughts, wishes or conceptions about what it might be. But that kind of realism is still a presumption, even it it seems pretty reasonable. And then one problem that QM poses is that the observer no longer seems independent of the observables. As in the twin slit experiment, the choices an observer makes becomes part of the reality in terms of the statistical outcomes.

So even if you personally choose not to believe this fact of QM, it remains something that has now been witnessed time and again. The fact is not disputed, just how it might best be interpreted in the light of what we might want to believe in terms of defending more classical notions of causality, such as one that still models events in terms of the principle of locality.

So whatever causality is "in the noumenal raw", we are going to understand that in terms of a model. And that is fine if our modelling is based on a desire to model the world as accurately as we can. Which pragmatically, cashes out as a measurable minimisation of our uncertainty or surprisal when it comes to the physics of the world. We never "know" causality, but we sure as heck can work towards the models that make the best possible predictions and so leave us with the least possible surprises.

On that score, we know that classical models of causality work fine when the scale of the Cosmos is cold and large, but not when the Cosmos is small and hot. That is when the quantum model of causality would have to take over - and the Big Bang tells us it is the more fundamental story, being the condition that ruled at the beginning.

So there is no danger of conflating our models of reality with that reality if we are pragmatists. But what is clear is that science has found that different models sum up the story of causality at different scales of being. And yet you are insisting you can go beyond the models to see how things really are. You can believe in a classical causality as the true story rather than as merely one of a couple of models we can usefully employ to measurably good effect.

From a scientists point of view, this is a little crazy. Even classical Newtonian determinism is known to be full of causal paradox. The principle of least action is as basic a physical axiom as the principle of locality, and yet that involves "spooky action at a distance". Every event would have to know its future outcome so as to follow the path with the least action. Even Newtonianism has this "effect dictates the cause" back-arsewardness to it.

And even if we now have quantum theory as our most accurate predictive model, we know it doesn't completely capture the causal story. QM has been relativised. The need to account for observer collapse has been worked around by tacking on statistical mechanics - the contextual thermodynamic decoherence story - as a kluge. But including gravity and thus spacetime fluctuations in the formalism is work in progress.

So the point is that classical physics never actually supported a simple cause and effect ontology. It relied on some weird least action principle to actually determine every trajectory. And then QM brought least action to the fore as one of the causal things it was going to fix. The path integral formalism showed how reality must in some sense take every possible path and then sum over the possibilities. But QM can't yet deal with the contributions of gravitational fluctuations - at least right down to the Planck scale limit where they start to completely overwhelm any conventional causal structure.

Science thus tells us that we don't actually understand causality, but we have gone a long way towards telling a more complete feeling story. We are acknowledging the modelling gaps and seeking to plug them with mathematical machinery.

Yet you, in contrast, seem to be saying you can see cause and effect with your own eyes. Every question you could have about the way the world is has already been answered.

If QM can undermine causality, — Harry Hindu

QM undermines classical causality. QM puts forward its own causal story. Experiment determines which story we are inclined to believe. It's really simple.

Yep, so you are making some confused epistemic point about our models of reality. — apokrisis

The point is clear, and not at all confusing or confused...

Pots and kettles...

I'm pointing out the inherent conflation in your position, namely that you're not drawing the distinction between your report and what's being reported upon(causality, in this case). Sometimes there is no relevant difference, as with QM. Other times, there is a substantial difference, as with causality.

To hold that QM is the basis of causality is asinine. We could debate this if you like. There's a forum for it.

But that kind of realism is still a presumption, even it it seems pretty reasonable. — apokrisis

:up:

I've just about finished Adam Becker's recent book What is Real? He says that Einstein's scientific realism was right all along, and Niels Bohr et al were obscurantists; he makes his disdain for Heisenberg palpable. And he says that the Bell theorem and Aspect experiments have also undermined the Copenhagen interpretation. I don't agree with his analysis at all, although it's a pretty well-written and researched book. (I think Everett comes across dreadfully and again am baffled by the traction his ideas have gotten.)

Here's my take... — creativesoul

What I was taking issue with was the first sentence: that maths doesn't do anything observable. It makes predictions, which are then validated against observation. So maybe pure maths doesn't 'do anything observable', but mathematical physics does a great deal. Also that quantum mechanics is more than maths, it is applied maths. But agree that obviously quantum mechanics is baffling, to paraphrase Bohr again, if you don't think it's baffling then you don't know what it's about.

Math doesn't do anything observable. It's a tool of measurement. Quantum mechanics is math. Quantum mechanics is understood if someone understands the formulas, principles, and rules of doing it. — creativesoul

What is at issue in all this is as per the title of the book: what is real? It seems blaringly obvious to me that quantum physics challenges any realist ontology. That is what makes it such a political hot potato - Becker notes that, once the military-industrial complex basically took over a lot of physics research after WWII, speculation on the meaning of quantum physics basically became a career killer (with some exceptions, e.g. Alain Aspect, who has, apparently, extraordinarily gifted communications abilities.) Likewise now if you post a thread about this kind of topic on Physics Forum it gets very short shrift; they're basically banned there.

But from a philosophical point of view, I still think what is being challenged is indeed the reality of the physical realm. If you find that 'the observer' is inextricably a part of it - and this seems to be the very problem that Everett's drunken epiphany sought to eliminate - then you cast doubt on the scientific worldview qua worldview. It was the absence of 'observer independence' that bothered the s***t out of Einstein and Bell:

The discomfort that I feel is associated with the fact that the observed perfect quantum correlations seem to demand something like the "genetic" hypothesis. For me, it is so reasonable to assume that the photons in those experiments carry with them programs, which have been correlated in advance, telling them how to behave. This is so rational that I think that when Einstein saw that, and the others refused to see it, he was the rational man. The other people, although history has justified them, were burying their heads in the sand. I feel that Einstein's intellectual superiority over Bohr, in this instance, was enormous; a vast gulf between the man who saw clearly what was needed, and the obscurantist. So for me, it is a pity that Einstein's idea doesn't work. The reasonable thing just doesn't work.

John Stewart Bell (1928-1990), quoted in Quantum Profiles, by Jeremy Bernstein [Princeton University Press, 1991, p. 84]

I'm pointing out the inherent conflation in your position, namely that you're not drawing the distinction between your report and what's being reported upon(causality, in this case). — creativesoul

Maybe you still just fail to understand pragmatism then?

How could I be conflating the model with the reality when I am talking about our models of reality? But then the "report" in your terminology must be the mediating thing of a measurement, or observation, or sign. And the "report" does underwrite the conception. It is the particular that inductively confirms the generality of some theory.

That is how it is meant to work. You haven't shown any problem with it.

If you get hit by a rock falling out of the sky, you could assign that physical fact to various theories. It could be a malicious god taking careful aim at you. Or it could be a random accident - a bit of falling space junk.

In the one example, you would report being struck by a divine missile. In the other, you would report being struck by a fluke accident.

So "what is being reported" is some particular ... that relates interpretatively to some generality. You have two possible causal interpretations. You wind up reporting the version you have some habit of believing.

Pragmatism draws out this full triadic relation of theory, measurement and world. It does the opposite of conflating in doing so.

To hold that QM is the basis of causality is asinine. — creativesoul

But that is just your weird phrasing of what is being said.

I said QM challenges the kind of classically linear, cause-and-effect, model of causality which you would appear to hope to assimiliate all your experiences to.

So you have some habit of mind. You think you know what causality actually is in its true natural form. But as I've argued at length, even classical physics conceals basic challenges to that. The least action principle doesn't fit that story.

And then QM really rocks any remaining faith in it. We know that causality can't be locally real. Or at best, that it is only a macroscale emergent phenomenon. Like the liquidity of water, it is a collective state of order that arises when the Universe has got so large and cold that any lingering QM uncertainty or weirdness has been shrunk mostly out of sight.

So what is asinine is pretending that simple linear causal logic ever really applied to the observable physical world. Even Newtonian physics knew there was more to the story. QM proves there has to be much more.

What I was taking issue with was the first sentence: that maths doesn't do anything observable. It makes predictions, which are then validated against observation. So maybe pure maths doesn't 'do anything observable', but mathematical physics does a great deal. — Wayfarer

I can understand how that could be a statement hard to agree with. It's true though.

In the context, it was a direct reply to apo claiming "with quantum mechanics, what is witnessed..." That is nonsense talk. Apo glosses over too many clear problems and/or refutations. We can do all kinds of stuff with math. Math doesn't do anything. Same with words. The point I was making is a basic one. I offered adequate argument against the notion that QM is fundamental to causality. Apo ignored all of it.