[ExI] Quantum Bayesianism (QBism)

[Keith Henson]

I have been aware of many worlds for a long time.  It was a staple of
SF for ages.  I made an awful joke about it (and because it could be
harmful) I didn't write about it for a long time.

However, I can't see that my opinion of many worlds or free will has
any practical application or that any of this affects or would affect
my behavior.


Keith

On Fri, Sep 8, 2023 at 3:35 AM BillK via extropy-chat
<extropy-chat at lists.extropy.org> wrote:
>
> QBism seems to be becoming popular, with more articles appearing.
>
> <https://theconversation.com/qbism-quantum-mechanics-is-not-a-description-of-objective-reality-it-reveals-a-world-of-genuine-free-will-200487>
> Quote:
> ‘QBism’: quantum mechanics is not a description of objective reality –
> it reveals a world of genuine free will   By: Ruediger Schack
> Published: March 29, 2023
>
> <https://medium.com/physics-philosophy-more/qbism-a-technical-discourse-34109e2b3c16>
> Quote:
> QBism — A technical discourse
> Sanjay Basu, PhD     May 25, 2023
> Unraveling QBism: A Deep Dive into Quantum Bayesianism
>
>
> I asked AI to summarize and explain QBism:
>
> QBism, also known as Quantum Bayesianism, is a philosophical
> interpretation of quantum mechanics that combines elements of
> subjective probability and Bayesian reasoning. It was developed by
> physicist Christopher Fuchs and his colleagues in the early 2000s as a
> response to the long-standing interpretational issues and paradoxes in
> quantum theory.
>
> At its core, QBism asserts that quantum mechanics is fundamentally
> about an agent's personal beliefs or degrees of belief rather than
> objective reality. It emphasizes the role of the observer and their
> subjective experiences in understanding quantum phenomena. According
> to QBism, the wave function, which describes the state of a quantum
> system, represents an agent's personal probabilities or expectations
> for different measurement outcomes.
>
> In QBism, probabilities are understood as subjective degrees of belief
> rather than objective frequencies or propensities. These probabilities
> are updated using Bayesian inference, a mathematical framework for
> updating beliefs based on new evidence. The agent's beliefs are
> represented by a probability distribution over possible measurement
> outcomes, and this distribution is updated using Bayes' theorem after
> each measurement.
>
> One key aspect of QBism is its rejection of the idea that quantum
> systems have definite properties before they are measured. Instead, it
> argues that these properties only exist in relation to an observer's
> measurements and their subjective beliefs. This view is often referred
> to as "participatory realism," as it suggests that reality is created
> through the interaction between the observer and the observed system.
>
> Another important concept in QBism is the notion of "quantum states as
> personalist Bayesian agents." According to this idea, quantum systems
> can be thought of as agents that update their own beliefs based on
> their interactions with other systems. This perspective allows for a
> more intuitive understanding of entanglement and non-locality in
> quantum mechanics.
>
> QBism also addresses the long-standing debate between wave-particle
> duality and the collapse of the wave function. It suggests that these
> concepts are not fundamental but rather emerge from an agent's
> interactions with quantum systems. The wave function is seen as a tool
> for making predictions about measurement outcomes, rather than a
> physical entity.
>
> Overall, QBism offers a new perspective on the interpretation of
> quantum mechanics that places the observer and their subjective
> beliefs at the center of the theory. It provides a framework for
> understanding quantum phenomena in terms of personal probabilities and
> Bayesian reasoning, challenging traditional notions of objective
> reality.
> -----------------
>
>
> So, Many Worlds Interpretation is not required with QBism.
>
> BillK
>
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