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Physicists provide support for retrocausal quantum theory

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Re: Physicists provide support for retrocausal quantum theory

#31

Post by JadeNB »

ridewinter wrote: post #15

The many-worlds interpretation of quantum mechanics is the only one that's easy to understand. All others seem to bend over backwards to realistically explain quantum effects. It's so rare to find clear explanations, but they do exist. My favorite from David Deutsch, a main creator of the idea of quantum computing: To those who still cling to a single-universe world-view, I issue this challenge: explain how Shor’s al…

> My favorite from David Deutsch, a main creator of the idea of quantum computing:

It's interesting, but this "I challenge you to answer a philosophical (not scientific) question in a way that I find acceptable" approach surely skirts uncomfortably close to dogmatically creationist arguments.

(For the record, my answer, which certainly wouldn't satisfy Deutsch, is: it works because the math proves it works; there's no more "how" about it than there is in "how does the computation 10^(250)*10^(250) = 10^(500) work?")

Re: Physicists provide support for retrocausal quantum theory

#32

Post by adrianN »

ridewinter wrote: post #30
ethn wrote: post #26

Earlier quoted context omitted.

First if you can measure it then it must be in ~physical reality~. If we are directly interacting with it why even consider it to be in another universe? Is my keyboard also in another universe? Second, since when is one atom responsible for a computation? In modern electronics no atom is responsible at all for computation, only the electrons are†. Even then, computation is an emergent property, computation itself is…

The coolness of quantum computing is that it harnesses the natural computational abilities of reality itself. So a single atom is doing an amazing number of quantum calculations at any moment. These guys like Deutsch figured out how to harness those calculations. And the only way to interact with parallel universes is if they are totally identical except what's inside of the quantum computer itself. Deutsch posits th…

All computing machines harness the universe's innate ability for computation. Quantum computers just do it better.

Re: Physicists provide support for retrocausal quantum theory

#33

Post by ridewinter »

mikeash wrote: post #24
ridewinter wrote: post #15

The many-worlds interpretation of quantum mechanics is the only one that's easy to understand. All others seem to bend over backwards to realistically explain quantum effects. It's so rare to find clear explanations, but they do exist. My favorite from David Deutsch, a main creator of the idea of quantum computing: To those who still cling to a single-universe world-view, I issue this challenge: explain how Shor’s al…

That seems to be begging the question. Qubits do more than this universe is capable of, therefore there must be multiple universes. The obvious refutation is: qubits don't do more than this universe is capable of, because the universe does not run on classical limits. 10^80 atoms implying on the order of 10^80 computations that can be done implicitly assumes that these things operate on classical-ish rules. There's a…

Explain the double slit experiment to me. The single photon somehow calculates the interference pattern with photons that don't exist, in our world at least. If there's not parallel universes, how does a single atom calculate that interference pattern? Where do those calculations occur? All other theories say it happens by magic and give all sorts of complicated non-real obfuscations to explain it.

Re: Physicists provide support for retrocausal quantum theory

#34

Post by miltondts »

Lxr wrote: post #18

I never fully understood the Bell experiments. How exactly do they discount hidden variables?

They don't here is what Bell said:

"There is a way to escape the inference of superluminal speeds and spooky action at a distance. But it involves absolute determinism in the universe, the complete absence of free will. Suppose the world is super-deterministic, with not just inanimate nature running on behind-the-scenes clockwork, but with our behavior, including our belief that we are free to choose to do one experiment rather than another, absolutely predetermined, including the ‘decision’ by the experimenter to carry out one set of measurements rather than another, the difficulty disappears. There is no need for a faster-than-light signal to tell particle A what measurement has been carried out on particle B, because the universe, including particle A, already ‘knows’ what that measurement, and its outcome, will be."

Re: Physicists provide support for retrocausal quantum theory

#35

Post by rf15 »

mirekrusin wrote: post #13

// WARN: because past is static, to support retrocausal influence, we're spawning alternative universes which are joined on retrocausal action choice - this slows down The Simulation and, if abused, can exhaust resources and crash.

don't remind me that people actually believe that you can infer the existence of a simulation only with data points that are created and controlled by it.

Re: Physicists provide support for retrocausal quantum theory

#36

Post by opportune »

JadeNB wrote: post #31
ridewinter wrote: post #15

The many-worlds interpretation of quantum mechanics is the only one that's easy to understand. All others seem to bend over backwards to realistically explain quantum effects. It's so rare to find clear explanations, but they do exist. My favorite from David Deutsch, a main creator of the idea of quantum computing: To those who still cling to a single-universe world-view, I issue this challenge: explain how Shor’s al…

> My favorite from David Deutsch, a main creator of the idea of quantum computing: It's interesting, but this "I challenge you to answer a philosophical (not scientific) question in a way that I find acceptable" approach surely skirts uncomfortably close to dogmatically creationist arguments. (For the record, my answer, which certainly wouldn't satisfy Deutsch, is: it works because the math proves it works; there's n…

I agree with you. I think the need for philosophical justification stems from our desire to reconcile quantum computing with our classical computing/physics models. But just because we desire such a thing doesn't mean there exists a reasonable one.

What I think the truth really is, is that we don't encounter quantum superpositions in an obvious way in our day to day lives. So it's inherently "weird" for us, especially since it seems to violate our notion of object permanence. But that doesn't mean it's wrong, it just means that one of our evolved instincts isn't applicable on a quantum scale.

Re: Physicists provide support for retrocausal quantum theory

#37

Post by ethn »

ridewinter wrote: post #30
ethn wrote: post #26

Earlier quoted context omitted.

First if you can measure it then it must be in ~physical reality~. If we are directly interacting with it why even consider it to be in another universe? Is my keyboard also in another universe? Second, since when is one atom responsible for a computation? In modern electronics no atom is responsible at all for computation, only the electrons are†. Even then, computation is an emergent property, computation itself is…

The coolness of quantum computing is that it harnesses the natural computational abilities of reality itself. So a single atom is doing an amazing number of quantum calculations at any moment. These guys like Deutsch figured out how to harness those calculations. And the only way to interact with parallel universes is if they are totally identical except what's inside of the quantum computer itself. Deutsch posits th…

You didn't defend Deutsch's erroneous assumption that atoms are responsible for physical interactions in computation. Even in quantum computing atoms are not responsible for any computation––especially if you have a system like DWave which uses magnetically induced currents.

"The natural computational abilities of reality itself"

Additionally you continue to insist that computation is a real physical thing. Are you claiming that nature is aware of the states we assign it to perform computation?

The way computation works is that we map various physical states with our own semantic abstractions. I can change the computation for addition into one for subtraction without any physical change to the system. So there is no harnessing of "the natural computational abilities of reality itself". We merely observe natural behavior and semantically map it (which is what engineering is).

Re: Physicists provide support for retrocausal quantum theory

#38

Post by raverbashing »

ridewinter wrote: post #33
mikeash wrote: post #24

Earlier quoted context omitted.

That seems to be begging the question. Qubits do more than this universe is capable of, therefore there must be multiple universes. The obvious refutation is: qubits don't do more than this universe is capable of, because the universe does not run on classical limits. 10^80 atoms implying on the order of 10^80 computations that can be done implicitly assumes that these things operate on classical-ish rules. There's a…

Explain the double slit experiment to me. The single photon somehow calculates the interference pattern with photons that don't exist, in our world at least. If there's not parallel universes, how does a single atom calculate that interference pattern? Where do those calculations occur? All other theories say it happens by magic and give all sorts of complicated non-real obfuscations to explain it.

Bohmian mechanics seems like a better explanation than "there are infinite universes out there"

Re: Physicists provide support for retrocausal quantum theory

#39

Post by ridewinter »

ethn wrote: post #37
ridewinter wrote: post #30

Earlier quoted context omitted.

The coolness of quantum computing is that it harnesses the natural computational abilities of reality itself. So a single atom is doing an amazing number of quantum calculations at any moment. These guys like Deutsch figured out how to harness those calculations. And the only way to interact with parallel universes is if they are totally identical except what's inside of the quantum computer itself. Deutsch posits th…

You didn't defend Deutsch's erroneous assumption that atoms are responsible for physical interactions in computation. Even in quantum computing atoms are not responsible for any computation––especially if you have a system like DWave which uses magnetically induced currents. "The natural computational abilities of reality itself" Additionally you continue to insist that computation is a real physical thing. Are you c…

Take the interference pattern built in the famous double slit experiment: what Deutsch and other recognized is that there's computation happening to create that pattern. And similar computation is present in all quantum effects. Quantum computers in effect harness that natural computational power. I don't fully understand how, but Deutsch proved that you can create a general computing machine from those natural quantum computations. Amazing.

Re: Physicists provide support for retrocausal quantum theory

#40

Post by mr_overalls »

raverbashing wrote: post #38
ridewinter wrote: post #33

Earlier quoted context omitted.

Explain the double slit experiment to me. The single photon somehow calculates the interference pattern with photons that don't exist, in our world at least. If there's not parallel universes, how does a single atom calculate that interference pattern? Where do those calculations occur? All other theories say it happens by magic and give all sorts of complicated non-real obfuscations to explain it.

Bohmian mechanics seems like a better explanation than "there are infinite universes out there"

"We don't understand the deeper mechanisms yet" is also a valid explanation - although one that's sure to be unpopular with scientists.

"Entia non sunt multiplicanda praeter necessitatem" and all that.

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