Mar 30, 2023 05:25 PM
The colorful problem that has long frustrated mathematicians
https://www.quantamagazine.org/only-comp...-20230329/
The four-color problem is simple to explain, but its complex proof continues to be both celebrated and despised.
QBism’: quantum mechanics is not a description of objective reality – it reveals a world of genuine free will
https://theconversation.com/qbism-quantu...ill-200487
EXCERPTS: . . . The use of the word “agent” rather than the familiar “observer” highlights that quantum mechanics is about actions that participate in creating reality, rather than observations of a reality that exists independently of the agent. [...] QBism does not attempt to represent reality. It does not attempt to bring the different perspectives together in one “third-person” view. QBism is fundamentally anti-representational and first person.
This puts QBism in direct contradiction with the two pillars of the 19th-century conception of a mechanistic universe. One is that nature is governed by physical laws in the same way that a mechanical toy is governed by its mechanism. The other is that it is, in principle, possible to have an objective view of the universe from the outside – from a God’s eye or third-person standpoint.
This mechanistic vision is still dominant among 21st-century scientists. [...] the QBist vision is that of an unfinished universe, of a world that allows for genuine freedom, a world in which agents matter and participate in the making of reality.
[...] A key aspect of quantum mechanics is randomness. Rather than making firm predictions, quantum mechanics is concerned with the probabilities for potential measurement outcomes. The physicist Ed Jaynes famously expressed that to understand quantum mechanics, one has to understand probability first.
In this spirit, QBism’s starting point is the personalist Bayesian approach to probability (originally a method of statistical inference and now a fully fledged theory of decision making under uncertainty). In this approach, probabilities are an agent’s personal degrees of belief.
So rather than describing the statistics of some experiment, probabilities provide guidance to agents on how they should act. In other words, probabilities are not descriptive but “normative” – analogous to an instruction manual. It turns out that the standard probability rules can be derived from the (normative) principle that one’s probabilities should fit together in a way that guards against a sure loss when used for making decisions.
QBism’s great insight was that the probabilities that appear in quantum mechanics are no different. They are not, as in the standard view, fixed by physical law, but express an agent’s personal degrees of belief about the consequences of measurement actions the agent is contemplating.
[...] Just like “observer”, the term “measurement” can be misleading because it suggests a pre-existing property that is revealed by the measurement. Instead, a measurement should be thought of as an action an agent takes to elicit a response from the world. A measurement is an act of creation that brings something entirely new into the world, an outcome that is shared between the agent and the agent’s external world.
Quantum mechanics is often depicted as “weird” and hard, or indeed impossible, to understand. As a matter of fact, the weirdness of quantum mechanics is an artefact of looking at it the wrong way. Once the two main QBist insights - that the quantum rules are guides to action and that measurements do not reveal pre-existing properties - are taken on board, all quantum paradoxes disappear... (MORE - missing details)
https://www.quantamagazine.org/only-comp...-20230329/
The four-color problem is simple to explain, but its complex proof continues to be both celebrated and despised.
QBism’: quantum mechanics is not a description of objective reality – it reveals a world of genuine free will
https://theconversation.com/qbism-quantu...ill-200487
EXCERPTS: . . . The use of the word “agent” rather than the familiar “observer” highlights that quantum mechanics is about actions that participate in creating reality, rather than observations of a reality that exists independently of the agent. [...] QBism does not attempt to represent reality. It does not attempt to bring the different perspectives together in one “third-person” view. QBism is fundamentally anti-representational and first person.
This puts QBism in direct contradiction with the two pillars of the 19th-century conception of a mechanistic universe. One is that nature is governed by physical laws in the same way that a mechanical toy is governed by its mechanism. The other is that it is, in principle, possible to have an objective view of the universe from the outside – from a God’s eye or third-person standpoint.
This mechanistic vision is still dominant among 21st-century scientists. [...] the QBist vision is that of an unfinished universe, of a world that allows for genuine freedom, a world in which agents matter and participate in the making of reality.
[...] A key aspect of quantum mechanics is randomness. Rather than making firm predictions, quantum mechanics is concerned with the probabilities for potential measurement outcomes. The physicist Ed Jaynes famously expressed that to understand quantum mechanics, one has to understand probability first.
In this spirit, QBism’s starting point is the personalist Bayesian approach to probability (originally a method of statistical inference and now a fully fledged theory of decision making under uncertainty). In this approach, probabilities are an agent’s personal degrees of belief.
So rather than describing the statistics of some experiment, probabilities provide guidance to agents on how they should act. In other words, probabilities are not descriptive but “normative” – analogous to an instruction manual. It turns out that the standard probability rules can be derived from the (normative) principle that one’s probabilities should fit together in a way that guards against a sure loss when used for making decisions.
QBism’s great insight was that the probabilities that appear in quantum mechanics are no different. They are not, as in the standard view, fixed by physical law, but express an agent’s personal degrees of belief about the consequences of measurement actions the agent is contemplating.
[...] Just like “observer”, the term “measurement” can be misleading because it suggests a pre-existing property that is revealed by the measurement. Instead, a measurement should be thought of as an action an agent takes to elicit a response from the world. A measurement is an act of creation that brings something entirely new into the world, an outcome that is shared between the agent and the agent’s external world.
Quantum mechanics is often depicted as “weird” and hard, or indeed impossible, to understand. As a matter of fact, the weirdness of quantum mechanics is an artefact of looking at it the wrong way. Once the two main QBist insights - that the quantum rules are guides to action and that measurements do not reveal pre-existing properties - are taken on board, all quantum paradoxes disappear... (MORE - missing details)