Article John Wheeler saw the tear in reality

[C C]

https://www.quantamagazine.org/john-whee...-20240925/

EXCERPTS: John Wheeler’s preoccupation with space-time began in the 1950s. General relativity — Einstein’s theory that matter and energy warp space-time and that this warping is gravity — had fallen into the backwaters of physics, outshined by progress in quantum mechanics. But in 1952, Wheeler had an idea: What if what we call “matter” is really just space-time? After all, he thought, gravity is a kind of energy, but gravity acts on energy, which means gravity acts on itself. He imagined waves of gravity folding themselves into compact spheres that would look like elementary particles from the outside, while on the inside they’d be made of nothing but empty space, “mass without mass.” He called them “geons (opens a new tab).” They would whittle down the ingredients of the universe to just one.

Particles also have charge. Could that, too, be reduced to geometry? Wheeler imagined a highly warped and twisted space-time, “multiply connected,” with holes and handles wrapping in and around themselves. Electric field lines woven through this gnarled landscape could disappear into one hole, burrow through space-time, then reemerge from another. Where they disappeared, it would look like there was a negatively charged particle, and where they reappeared, a positive one. In truth, there would be neither, just electric field lines endlessly looping back on themselves, creating “charge without charge.”

No one had ever used general relativity in this way, bending and contorting space-time until the rest of physics poured right out, rendering the universe full of strange twists and tunnels so new they didn’t have names. Wheeler gave them one: wormholes. That’s what he was best at —naming things, yes, but also taking preexisting theories and pushing them to their limits to see where they break. What happens when you get to the end of things?

[...] He guessed that quantum fluctuations of space-time could transform a tranquil geometry into a mangled maze, which Wheeler called “quantum foam.” It seemed to be just what was needed for geons to exist.

It then occurred to Wheeler that at scales smaller still — the infamous Planck length, on the order of 10^-33 centimeters — quantum uncertainty could destroy space-time altogether. Localized points like “here” and “there” would be rendered meaningless. He wanted to build everything in the universe out of space-time, but it wasn’t clear if space-time would survive.

[...] Could pregeometry be made of “grains” of space-time, he asked? No, that would assume too much structure.

He had a better idea: Perhaps it was made of information — 1s and 0s, yeses and nos, binary choices. “The dimension-free character of the bit at last frees us from the dimension-tyrannized land of … everyday physics of particles, fields, of space-time,” he wrote. But the question keeping him up at night was, whose information?

It dawned on Wheeler (opens a new tab) that when space and time went, taking the rest of physics with them, there was something left. “With law going and chaos arriving, one principle remains,” Wheeler wrote. “The quantum principle.” Quantum mechanics, he wrote, “destroys the concept of the world as ‘sitting out there,’ with the observer safely separated from it by a 20 centimeter slab of plate glass. Even to observe so miniscule an object as an electron, he must shatter the glass. He must reach in. … The universe will never afterwards be the same. To describe what has happened, one has to cross out that old word ‘observer’ and put in its place the new word ‘participator.’ In some strange sense the universe is a participatory universe.”

It was officially the wildest idea he’d had yet. A universe made not of matter, not of space-time, not of stuff at all, but of our choices. It wasn’t what he’d hoped to find; the physics had led him there. He’d pried up space-time, peered beneath, and found himself staring, to his bewilderment, at a mirror. “One finds himself in desperation asking if the structure, rather than terminating in some smallest object or in some most basic field, or going on and on, does not lead back in the end to the observer.” (MORE - missing details)

[Magical Realist]

I think Wheeler took the implications of quantum science as far as possible, showing the truly derivative nature of all physical/measurable phenomena in the universe, and then came up against an inevitable conundrum: how can a reality generated by our own observation/choices be only one self-same reality shared by all minds? His dying thought was that perhaps hope creates this participatory reality. Hope perhaps as the future--of reality being essentially always open and undetermined as to what it ultimately is. It makes for a rather slippery and zen-like worldview, that what is "in itself" is fleeting and illusory, always giving way to change and becoming. As coherent and certain as our scientific model of reality might be, there is always the mystery of its ongoing and incomprehensible meaning in our lives and experience. Perhaps a mystery only penetrated when we "shuffle off this mortal coil."

[geordief]

Most people  I read on the internet have said that the "observer" doesn't create the reality but that it is the interactions that cause the reality.(that the system is indererminate until there is an interaction  and then it is determined  but only for that instant -the collapse of the wavefunction is it?)

I thought the idea that. an act of conscious observation was  involved had been abandoned.

This is the first time I have encountered someone who thought that a conscious observer had any bearing on the physics involved and I am surprised it was someone as well known as Wheeler and that he never seems to have given up on the idea.

Are there other reputable scientists who still plough this furrow?

[Magical Realist]

This is the first time I have encountered someone who thought that a conscious observer had any bearing on the physics involved and I am surprised it was someone as well known as Wheeler and that he never seems to have given up on the idea.

The Copenhagen interpretation became the most popular interpretation among physicists for a long time. But over the years the idea that the wave collapse always required a conscious observer was abandoned by many and interpreted in terms of any interaction with a measuring device. And decoherence caused by environmental interaction has been claimed to cause it though not really. (see below citation). So that's probably why nowadays you don't hear of many physicists espousing the "consciousness" view of the wave collapse. Few are prepared to live with the metaphysically idealistic consequences of that explanation as Wheeler tried to.

"Decoherence has been used to understand the possibility of the collapse of the wave function in quantum mechanics. Decoherence does not generate actual wave-function collapse. It only provides a framework for apparent wave-function collapse, as the quantum nature of the system "leaks" into the environment. That is, components of the wave function are decoupled from a coherent system and acquire phases from their immediate surroundings. A total superposition of the global or universal wavefunction still exists (and remains coherent at the global level), but its ultimate fate remains an interpretational issue."---- https://en.wikipedia.org/wiki/Quantum_decoherence

[geordief]

This is the first time I have encountered someone who thought that a conscious observer had any bearing on the physics involved and I am surprised it was someone as well known as Wheeler and that he never seems to have given up on the idea.

The Copenhagen interpretation became the most popular interpretation among physicists for a long time. But over the years the idea that the wave collapse always required a conscious observer was abandoned by many and interpreted in terms of any interaction with a measuring device. And decoherence caused by environmental interaction has been claimed to cause it though not really. (see below citation). So that's probably why nowadays you don't hear of many physicists espousing the "consciousness" view of the wave collapse.  Few are prepared to live with the metaphysically idealistic consequences of that explanation as Wheeler tried to.

  "Decoherence has been used to understand the possibility of the collapse of the wave function in quantum mechanics. Decoherence does not generate actual wave-function collapse. It only provides a framework for apparent wave-function collapse, as the quantum nature of the system "leaks" into the environment. That is, components of the wave function are decoupled from a coherent system and acquire phases from their immediate surroundings. A total superposition of the global or universal wavefunction still exists (and remains coherent at the global level), but its ultimate fate remains an interpretational issue."---- https://en.wikipedia.org/wiki/Quantum_decoherence

Yes ,that chimes with what I have read over the past few years.

Have there ever been any experiments suggested that might conceivably  show that the act of conscious observation plays no direct  part in  physical  outcomes on the quantum level or is the  argument that there is no need to introduce it as  things can be perfectly well understood   without the need for it (Occam's razor?)

[C C]

Have there ever been any experiments suggested that might conceivably show that the act of conscious observation plays no direct part in physical outcomes [...]

In quantum computers, the superposition of a qubit has to be protected through the fleeting process. No human observer is needed to compromise the superposition. The environment is what has to be prevented from interacting with qubits.

Decoherence fell out of work on the Everett Interpretation (Many Worlds) by H. Dieter Zeh. While the latter clung to EI, one of those influenced by him -- Wojciech Zurek -- went in arguably more of a metaphysical agnosticism direction (like Bohr/Heisenberg or the Copenhagen Interpretation). 

Decoherence accounts for how the superposition of different states in a quantum system (that were in phase with each other) lose their coherence in the course of interaction with the environment, and thereby behave classically.

What decoherence avoids is traditional wave function collapse, and that being caused by an "observer".

But decoherence doesn't fully solve the measurement problem. Since that involves having to choose one of the philosophical interpretations (like Many Worlds -- which uses decoherence), to explain why only one outcome is ultimately observable. Otherwise, agnosticism prevails as to the "why" or "how".

As aforementioned, one of the alternatives to the Everett Interpretation (Many Worlds) is Zurek's own project, which is called Quantum Darwinism (below). By dodging around Many Worlds, Zurek may have even enabled the popularity of decoherence. But his view wallows around in a lot of abstraction, making it unclear how "real" certain aspects are supposed to be. The very kind of ambiguity that would be the goal if -- like the Copenhagen Interpretation -- he wanted to avoid ontological issues. 

Quantum Darwinism
https://www.quantamagazine.org/quantum-d...-20190722/

EXCERPTS: This process by which “quantumness” disappears into the environment is called decoherence. It’s a crucial part of the quantum-classical transition, explaining why quantum behavior becomes hard to see in large systems with many interacting particles. The process happens extremely fast...

[...] Surprisingly, although decoherence is a straightforward consequence of quantum mechanics, it was only identified in the 1970s, by the late German physicist Heinz-Dieter Zeh. The Polish-American physicist Wojciech Zurek further developed the idea in the early 1980s and made it better known, and there is now good experimental support for it.

But to explain the emergence of objective, classical reality, it’s not enough to say that decoherence washes away quantum behavior and thereby makes it appear classical to an observer. Somehow, it’s possible for multiple observers to agree about the properties of quantum systems. Zurek, who works at Los Alamos National Laboratory in New Mexico, argues that two things must therefore be true.

First, quantum systems must have states that are especially robust in the face of disruptive decoherence by the environment. Zurek calls these “pointer states,” because they can be encoded in the possible states of a pointer on the dial of a measuring instrument. A particular location of a particle, for instance, or its speed, the value of its quantum spin, or its polarization direction can be registered as the position of a pointer on a measuring device. Zurek argues that classical behavior — the existence of well-defined, stable, objective properties — is possible only because pointer states of quantum objects exist.

[...] But there’s a second condition that a quantum property must meet to be observed. Although immunity to interaction with the environment assures the stability of a pointer state, we still have to get at the information about it somehow. We can do that only if it gets imprinted in the object’s environment. When you see an object, for example, that information is delivered to your retina by the photons scattering off it. They carry information to you in the form of a partial replica of certain aspects of the object, saying something about its position, shape and color. Lots of replicas are needed if many observers are to agree on a measured value — a hallmark of classicality. Thus, as Zurek argued in the 2000s, our ability to observe some property depends not only on whether it is selected as a pointer state, but also on how substantial a footprint it makes in the environment. The states that are best at creating replicas in the environment — the “fittest,” you might say — are the only ones accessible to measurement. That’s why Zurek calls the idea quantum Darwinism.

It turns out that the same stability property that promotes environment-induced superselection of pointer states also promotes quantum Darwinian fitness, or the capacity to generate replicas...
- - - - - - - - - - - - - - - - -

Decoherence and the interpretation problem
https://www.sciencedirect.com/science/ar...9809000562

EXCERPTS: This paper examines the interweaving of the history of quantum decoherence and the interpretation problem in quantum mechanics through the work of two physicists—H. Dieter Zeh and Wojciech Zurek. In the early 1970s Zeh anticipated many of the important concepts of decoherence, framing it within an Everett-type interpretation.

Zeh has since remained committed to this view; however, Zurek, whose papers in the 1980s were crucial in the treatment of the preferred basis problem and the subsequent development of density matrix formalism, has argued that decoherence leads to what he terms the ‘existential interpretation’, compatible with certain aspects of both Everett's relative-state formulation and the Bohr's ‘Copenhagen interpretation’.

[...] By the 1990s Zurek would defend the idea that decoherence does not compel one to adopt the many worlds interpretation, but rather it can be seen as bringing about something of a rapprochement between Everett's and Bohr's views, which he termed the ‘existential interpretation’. While a critical analysis of the interpretational commitments of Zeh and Zurek is beyond the scope of this paper, it is my contention that Zurek's work contributed in no small part to the view, which began to win ascent among both theoretical and experimental physicists in the 1990s, that decoherence provides a ‘completion’ or even a ‘justification’ of the original Copenhagen interpretation.

Thus, in contrast to Zeh's views that decoherence forces a radical departure from the Copenhagen orthodoxy, Zurek advanced the view that decoherence is compatible with, or even provides a confirmation of, many of Bohr's insights into quantum mechanics. To this extent, Zurek's work on decoherence can be understood as an attempt to provide a reconstruction of the original ‘Copenhagen interpretation’—reminiscent of Wheeler's attempt in the late 1950s—which serves to blur the traditional battle lines between ‘orthodox’ and ‘heterodox’ interpretations of quantum mechanics.

Here we see the way in which different understandings of the Copenhagen interpretation have continued to play a role in debates over the interpretation of quantum mechanics.1 Finally, I argue that it is only by attending to the different interpretive frameworks in which Zeh and Zurek presented their work on decoherence that we can better understand why Zeh's work was largely ignored, while Zurek's work attracted considerable interest. Put simply, my claim is that in the case of decoherence, interpretation influenced reception...

[geordief]

Have there ever been any experiments suggested that might conceivably show that the act of conscious observation plays no direct part in physical outcomes [...]

In quantum computers, the superposition of a qubit has to be protected through the fleeting process. No human observer is needed to compromise the superposition. The environment is what has to be prevented from interacting with qubits.

Decoherence fell out of work on the Everett Interpretation (Many Worlds) by H. Dieter Zeh. While the latter clung to EI, one of those influenced by him -- Wojciech Zurek -- went in arguably more of a metaphysical agnosticism direction (like Bohr/Heisenberg or the Copenhagen Interpretation). 

Decoherence accounts for how the superposition of different states in a quantum system (that were in phase with each other) lose their coherence in the course of interaction with the environment, and thereby behave classically.

What decoherence avoids is traditional wave function collapse, and that being caused by an "observer". 

But decoherence doesn't fully solve the measurement problem. Since that involves having to choose one of the philosophical interpretations (like Many Worlds -- which uses decoherence), to explain why only one outcome is ultimately observable. Otherwise, agnosticism prevails as to the "why" or "how".

As aforementioned, one of the alternatives to the Everett Interpretation (Many Worlds) is Zurek's own project, which is called Quantum Darwinism (below). By dodging around Many Worlds, Zurek may have even enabled the popularity of decoherence. But his view wallows around in a lot of abstraction, making it unclear how "real" certain aspects are supposed to be. The very kind of ambiguity that would be the goal if -- like the Copenhagen Interpretation -- he wanted to avoid ontological issues. 

Quantum Darwinism
https://www.quantamagazine.org/quantum-d...-20190722/

EXCERPTS: This process by which “quantumness” disappears into the environment is called decoherence. It’s a crucial part of the quantum-classical transition, explaining why quantum behavior becomes hard to see in large systems with many interacting particles. The process happens extremely fast...

[...] Surprisingly, although decoherence is a straightforward consequence of quantum mechanics, it was only identified in the 1970s, by the late German physicist Heinz-Dieter Zeh. The Polish-American physicist Wojciech Zurek further developed the idea in the early 1980s and made it better known, and there is now good experimental support for it.

But to explain the emergence of objective, classical reality, it’s not enough to say that decoherence washes away quantum behavior and thereby makes it appear classical to an observer. Somehow, it’s possible for multiple observers to agree about the properties of quantum systems. Zurek, who works at Los Alamos National Laboratory in New Mexico, argues that two things must therefore be true.

First, quantum systems must have states that are especially robust in the face of disruptive decoherence by the environment. Zurek calls these “pointer states,” because they can be encoded in the possible states of a pointer on the dial of a measuring instrument. A particular location of a particle, for instance, or its speed, the value of its quantum spin, or its polarization direction can be registered as the position of a pointer on a measuring device. Zurek argues that classical behavior — the existence of well-defined, stable, objective properties — is possible only because pointer states of quantum objects exist.

[...] But there’s a second condition that a quantum property must meet to be observed. Although immunity to interaction with the environment assures the stability of a pointer state, we still have to get at the information about it somehow. We can do that only if it gets imprinted in the object’s environment. When you see an object, for example, that information is delivered to your retina by the photons scattering off it. They carry information to you in the form of a partial replica of certain aspects of the object, saying something about its position, shape and color. Lots of replicas are needed if many observers are to agree on a measured value — a hallmark of classicality. Thus, as Zurek argued in the 2000s, our ability to observe some property depends not only on whether it is selected as a pointer state, but also on how substantial a footprint it makes in the environment. The states that are best at creating replicas in the environment — the “fittest,” you might say — are the only ones accessible to measurement. That’s why Zurek calls the idea quantum Darwinism.

It turns out that the same stability property that promotes environment-induced superselection of pointer states also promotes quantum Darwinian fitness, or the capacity to generate replicas...
- - - - - - - - - - - - - - - - -

Decoherence and the interpretation problem
https://www.sciencedirect.com/science/ar...9809000562

EXCERPTS: This paper examines the interweaving of the history of quantum decoherence and the interpretation problem in quantum mechanics through the work of two physicists—H. Dieter Zeh and Wojciech Zurek. In the early 1970s Zeh anticipated many of the important concepts of decoherence, framing it within an Everett-type interpretation.

Zeh has since remained committed to this view; however, Zurek, whose papers in the 1980s were crucial in the treatment of the preferred basis problem and the subsequent development of density matrix formalism, has argued that decoherence leads to what he terms the ‘existential interpretation’, compatible with certain aspects of both Everett's relative-state formulation and the Bohr's ‘Copenhagen interpretation’.

[...] By the 1990s Zurek would defend the idea that decoherence does not compel one to adopt the many worlds interpretation, but rather it can be seen as bringing about something of a rapprochement between Everett's and Bohr's views, which he termed the ‘existential interpretation’. While a critical analysis of the interpretational commitments of Zeh and Zurek is beyond the scope of this paper, it is my contention that Zurek's work contributed in no small part to the view, which began to win ascent among both theoretical and experimental physicists in the 1990s, that decoherence provides a ‘completion’ or even a ‘justification’ of the original Copenhagen interpretation.

Thus, in contrast to Zeh's views that decoherence forces a radical departure from the Copenhagen orthodoxy, Zurek advanced the view that decoherence is compatible with, or even provides a confirmation of, many of Bohr's insights into quantum mechanics. To this extent, Zurek's work on decoherence can be understood as an attempt to provide a reconstruction of the original ‘Copenhagen interpretation’—reminiscent of Wheeler's attempt in the late 1950s—which serves to blur the traditional battle lines between ‘orthodox’ and ‘heterodox’ interpretations of quantum mechanics.

Here we see the way in which different understandings of the Copenhagen interpretation have continued to play a role in debates over the interpretation of quantum mechanics.1 Finally, I argue that it is only by attending to the different interpretive frameworks in which Zeh and Zurek presented their work on decoherence that we can better understand why Zeh's work was largely ignored, while Zurek's work attracted considerable interest. Put simply, my claim is that in the case of decoherence, interpretation influenced reception...

Thanks for that.A pity I am such a slow  and lazy thinker .It will take me quite a while to familiarize myself with  the subject  -if ever(and that is seemingly just the interpretations  whereas I have next to no grounding in the nuts and bolts   of the  actual theory and experimental evidence...)

It seems to be a subject  where you can easily convince yourself you are entitled  to an opinion  whereas  the opposite is more likely.