What is Information?

I'm thinking that the answer is that the information referred to is Physical Information, all the characteristics of a physical system. It's not what we often consider as information like meaningful text versus random characters, and has nothing to do with an observer.

https://en.wikipedia.org/wiki/Physical_information

That information is not destroyed means that any change to the system is reversible, at least in principle. The system is completely described by the quantum wavefunction, which is completely deterministic, meaning that if you know the wavefunction now, you can determine the wavefunction in the past or future.

"Relevant principles[edit]

There are two main principles in play:^{[citation needed]}

• Quantum determinism means that given a present wave function, its future changes are uniquely determined by the evolution operator.
• Reversibility refers to the fact that the evolution operator has an inverse, meaning that the past wave functions are similarly unique.

The combination of the two means that information must always be preserved."

There is some question as to whether the information is lost if something falls into a black hole, and then the black hole eventually evaporates via Hawking radiation.

https://en.wikipedia.org/wiki/Black_hole_information_paradox

To the best of my understanding,which is dubious at best,the quantum "particles" are not necessarily in close proximity to each other,they could be separated by many light years, but they are inextricably linked by "spooky action at a distance" so that if one is drawn into the black hole's center,the other must dissipate an amount of energy equal to it's mass,to keep the "books balanced".
Theoretically, if the arrow of time is reversed,everything would go back to the singularity of the big bang.But there is evidence now that at the quantum level,the arrow can be reversed,with cold flowing to hot.
Perhaps the current expansion of the universe is just a portion of the long cycle of the universe,and eventually,everything will reverse,and collapse into a singularity,and when the last particle has been absorbed into the singularity,it reaches critical mass,and explodes again;another "Big Bang".
Humanity is a frog in a well and we are limited in what we will ever know due to our short time of existence.We will go extinct eventually,and so will many species that follow us,but the universe goes on,and does not care whether we understand it or not.It is incredible to me that we have learned as much as we have considering our brief time and minuscule size in relation to the greater whole.Still,we do not know where the mysterious "quantum particles" come from,so that is another chapter that has not been opened.Perhaps the expansion of space is caused by the energy of these particles being converted from mass to energy.

My understanding is also dubious at best. Two entangled quantum "particles" share a wavefunction, whatever that means, even if widely separated.

Most people, I believe, think of a magnetic field as a real thing. You can feel two magnets reacting to each other. To my understanding, no one knows whether a "wavefunction" is a real thing or just a mathematical description.

It's hard to understand how two particles widely separated can still communicate. Quantum theory (supported by experiment) has too many paradoxes. Nature is screaming at us - YOU HAVE A BAD ASSUMPTION SOMEPLACE!

Here is an interesting idea - retrocausality.

https://phys.org/news/2017-07-physicists-retrocausal-quantum-theory-future.html

"Information" is what an AP forgets to post when asking a question.

"Arrival" - a 2016 release starring Amy Adams, Forest Whitaker and Jeremy Renner, comes to mind.... Perhaps the best sci-fi movie I've seen so far.

You have weapon...

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What is 'information'?

well it is not something physical. That is the problem. You write something down, it then becomes whatever you wrote it with and on. It's graphite and wood pulp. its' life expectancy and the data that can be recorded is limited by the medium it was recorded with.

Does the 'information' change when it is written digitally as opposed to physically? Not at all, unless there is some character or expression limitation to the medium that requires a content change.

So, if 'information' is actually the electrical signal in the brain is it any different from any other physical form of record? is not the electrical signal in the brain basically the same as the electrical signal in the memory chip of your computer? formatted differently, probably, but was the 'information' altered or changed? no.

So energy arranged in a certain way/wave is the actual information. Does energy ever just go away? As far as I can tell the universe is not an open system meaning everything here always was here and always will be here. Just changing form, state, or expression.

The energy that is arranged in a specific form becomes information when we recognize it as such. Just because we don't understand something doesn't mean it doesn't exist. however, if that energy pattern is rearranged then the information contained in that pattern is no longer accessible to us as we did not undergo the same rearranging change. Does that information disappear? Only subjectively.

I mean a hydrogen atom is information. What it can tell us is only limited by our understanding but it has been the same since it coalesced. its related sub atomic particles will retain their 'information' whether combined as hydrogen or uranium.

Information is our interpretation of observed phenomena limited only by our understanding. a rather nebulous answer to a very nebulous question.

Which requires an observer,intelligence,and understanding.

Hows your cat?