Posted on September 21, 2021

### Rob Sheldon: “It from bit” is winning the cosmology wars | Uncommon Descent

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Ethan Siegel,

“Are we approaching quantum gravity all wrong?” at Big Think (September 16, 2021) -----

“gravity is emergent” from entropy that you can calculate based on the microscopic quantum state

of all the particles aggregated together.

Lee Smolin:"

the role of entropy in cosmological theory is something we have to get our heads straight about. “

Ethan :

“information” emerges from the particles . . . .

“entropy” or “information” emerges from the particles

Not only is “entropy” or “information” fundamental in the 21st century view of physics,

but in quantum information theory it is now held that “we wouldn’t say entropy is a property of a system,

but a property of an observer who describes a system.”,,,

Renato Renner, a professor ;

Fifteen years ago, “we thought of entropy as a property of a thermodynamic system,” . . .

“Now in (quantum) information theory, we wouldn’t say entropy is a property of a system,

but a property of an observer who describes a system.”,,,

“entropy is (not) a property of a system, but a property of an observer who describes a system.”

is with the quantum Zeno effect.

The reason why I am very impressed with the preceding experiments demonstrating that

“entropy is (not) a property of a system, but a property of an observer who describes a system”

is because entropy is very foundational in our scientific descriptions of the world.

As the following article states, “Entropy explains time; it explains every possible action in the universe;,,”,,

“Even gravity,,,, can be expressed as a consequence of the law of entropy.,,,”

Shining Light on Dark Energy – October 21, 2012

Excerpt: It (Entropy) explains time; it explains every possible action in the universe;,,

Even gravity can be expressed as a consequence of the law of entropy.,,,

The principles of thermodynamics are at their roots all to do with information theory.

Information theory is simply an embodiment of how we interact with the universe —,,,

Big bang by chance (?):

"The explosion in which our universe began was not a messy event." . . . .

And if you talk about how messy it could have been, this is what the Penrose calculation

is all about essentially. . . . This number has 10^123rd zeros.

Thus, considering entropy’s central importance in scientific explanation, (as well as in our own lives),

the statement “we wouldn’t say entropy is a property of a system, but a property of an observer

who describes a system.” is just fascinating!

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Where can "entropy" be used?

Entropy - in cosmological theory

Entropy - in quantum information theory

Entropy - is not only a property of a system, but also a property

of an observer who describes a system.

Entropy - can explain time

Entropy - can explain quantum gravity

Entropy - can explain every possible action in the universe

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John von Neumann said to the "father of information theory" Claude Shannon:

"Call it 'entropy', then in discussions you will get a solid advantage,

because no one knows what 'entropy' in general is."

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"Entropy" (1854 - 2021)

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