Is Causality in Quantum Mechanics as Clear-Cut as in Classical Mechanics?

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Discussion Overview

The discussion revolves around the nature of causality in quantum mechanics (QM) compared to classical mechanics (CM). Participants explore whether causality is as clear-cut in QM as it is in CM, examining implications for determinism and the predictability of events, particularly in the context of phenomena like radioactive decay.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Exploratory

Main Points Raised

  • Some participants assert that causality is present in QM, suggesting that while events are probabilistic, they are still caused.
  • Others argue that causality in QM is not as clear-cut, noting that certain events, like radioactive decay, appear to lack a definitive cause.
  • A participant highlights that QM allows for causality in a philosophical sense but challenges the notion of determinism, stating that QM does not permit exact predictions of events.
  • Another viewpoint emphasizes that while individual measurements in QM are probabilistic, the overall behavior of systems can be described deterministically through wave functions.
  • Some participants express skepticism about the completeness of QM, suggesting that it cannot predict actual events, only probabilities, and that this indicates a fundamental randomness in nature.
  • A later reply introduces the idea that the ontology of QM differs from CM, proposing that information about quantum states can deterministically influence future states, raising questions about the nature of information itself.
  • Several participants discuss the significance of single events in QM, with some arguing that these events cannot be dismissed as irrelevant, while others maintain that they do not provide sufficient information for deterministic predictions.

Areas of Agreement / Disagreement

Participants express a range of views on the nature of causality in QM, with no consensus reached. Some believe causality exists in a modified form, while others contend that certain effects may be causeless. The discussion remains unresolved regarding the implications of these differing perspectives on determinism and predictability.

Contextual Notes

Participants note limitations in the discussion, including the dependence on definitions of causality and determinism, as well as the unresolved nature of certain mathematical interpretations within QM.

  • #61
DrChinese said:
OK, so how does that relate to what "causes" the subsequent polarization value?

You need the "subsequent polarization value" first, before you are talking about what is "causing" it. The subsequent polarization value is just an another entanglement in between the observer and the photon. What you would get as a result is an observer in the superposition of two states. Now it would be up to an observer in some certain state to interpret his own state, and there is no problem with that. So there is no such thing, as the "defined subsequent polarization value", and there is no point of talking on what causes it.

-- Dmtr
 
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  • #62
Dmtr, you should call this concept Drtm.
 
  • #63
dmtr said:
You need the "subsequent polarization value" first, before you are talking about what is "causing" it. The subsequent polarization value is just an another entanglement in between the observer and the photon. What you would get as a result is an observer in the superposition of two states. Now it would be up to an observer in some certain state to interpret his own state, and there is no problem with that. So there is no such thing, as the "defined subsequent polarization value", and there is no point of talking on what causes it.

-- Dmtr

I have no clue to what you are talking about, but apparently we agree that there is no cause for the result.
 
  • #64
Galactor said:
It is my understanding that in classical mechanics, cause and effect are universally accepted.

Is it the same in QM? Is causality sound in QM?

It seems obvious that the role of determinism is not consistent with QM, but it too seems that all events (micro and macro) must have sufficient causes. A lack of causality argues for spontaneous emergence or the event being a first cause. It seems to me that all events will default back to available variables (sufficient causes). Otherwise, an event is based on nothingness or a lack of something, something without conditions or configurations or parameters. This seems to argue that acausality is based on nothing. Logically speaking, this makes no sense, an event then is either its own first cause (self causation), or it is based on available variables (causality of a larger system). I think some logic should be used in our interpretations.
 
  • #65
Descartz2000 said:
all events (micro and macro) must have sufficient causes. A lack of causality argues for spontaneous emergence or the event being a first cause.
Logically speaking, this makes no sense, an event then is either its own first cause (self causation), or it is based on available variables (causality of a larger system). I think some logic should be used in our interpretations.

Exactly. This is my position. However, there's no reason to think that logic can understand all the characteristic of reality. But there's no reason also to think the contrary. So we can only say that an event that seems random could be caused or not. But, in my opinion, we can't explain macroscopical causality without the assumption of microscopical causality for the reason that Descartz2000 has explained.

However, as DrChinese has underlined, this assumption is more phylosophical than purely mathematical/physical.

"Ai posteri l'ardua sentenza." (Manzoni, 5 Maggio)
 

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