Does energy exist?

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  • #1
KleinMoretti
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TL;DR Summary: does the quantity we refer to as energy actually exist

energy is a property of a physical system but does it actually exist, like does an object actually lose or gain a quantity that we refer to as energy after an interaction, or is it just a mathematical concept, are those mutually exclusive? From Feynman lectures (which is the source I have seen recommended the most to understand energy) "It is important to realize that in physics today, we have no knowledge of what energy is. We do not have a picture that energy comes in little blobs of a definite amount." This makes it seem like energy does represent something beyond a mathematical took but idk I maybe misinterpreting it.
 
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  • #2
Nothing in physics exists or everything in physics exists, depending on your definition of existence. In neither case does the theory or the experimental data change; hence, the physics does not change. It makes no difference whether we decide that energy exists or not.

This is, therefore, a philosophical question.
 
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  • #3
Energy is locally conserved, frame variant, and measurable. Some people think that things which are frame variant don’t exist. Some people think that things which are measurable do exist. Everybody thinks that things which are conserved are useful.
 
  • #4
Does velocity exist? Does mass exist? If it does, what does that mean?
 
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  • #5
Physicists employ double-entry bookkeeping, to account for the flow of the natural currency we call energy. Energy is an inherent and conserved property of a system. How could energy not be real to a Physicist?
 
  • #6
What is the difference between "exist" and "actually exist"? Is there a whole hierarchy of actually actuallies?
 
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  • #7
Vanadium 50 said:
What is the difference between "exist" and "actually exist"?
Is energy really real, or just literally real?
 
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  • #8
I don't know what the word "literally" means. I thought I did, but I have heard phrases like "I literally exploded" (did you now?) that I am no longer sure.
 
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  • #9
KleinMoretti said:
TL;DR Summary: does the quantity we refer to as energy actually exist
Energy not only exists, it is very expensive! :oops:

Many poor countries are supplying electrical energy to their populations only a few hours each day.

If while driving a vehicle, you ever run out of fuel in the middle of nowhere, and have to push that vehicle a few meters or feet, you inmediately come to the realization of how much energy that exhausted liquid in the tank had to offer.

Similar things can be told for other forms or manifestations of precious energy, without which, societies could not function as they do.
 
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  • #10
Vanadium 50 said:
What is the difference between "exist" and "actually exist"? Is there a whole hierarchy of actually actuallies?
what I meant is that energy is obviously present in our models and theories, but does that mean it exist?
 
  • #11
KleinMoretti said:
does that mean it exist?
People are giving you a hard time because that is such an ill-defined and non-physical question. The fact that you are repeating rather than clarifying does not make things clearer.
 
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  • #12
If I pick up a bowling ball I imbue it with potential energy. If I let it go, that potential energy gets converted to kinetic energy and eventually to the inelastic deformation of my big toe. These things are all measureable.

Let's pretend your premise is true - that energy does not exist. How does that help us understand or predict the above scenario? What about it is indicative that energy "does not exist"?
 
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  • #13
I think what you may be groping your way towards is the idea that energy less a particular thing than it is a bookkeeping system. The type of energy in the suspended bowling ball is different from the type of energy when it is falling, and is different from the type of energy when it breaks apart, producing heat, sound and a different manifestation of kinetic energy. We could also drop the ball in a kiln and watch it produce infra-red radiation as it heats up.
 
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  • #14
DaveC426913 said:
think what you may be groping your way towards is the idea that energy less a particular thing than it is a bookkeeping system
That's how I think about it.
 
  • #15
DaveC426913 said:
I think what you may be groping your way towards is the idea that energy less a particular thing than it is a bookkeeping system.
This is the way Feynman discussed the law of conservation of energy.
 
  • #16
KleinMoretti said:
what I meant is that energy is obviously present in our models and theories, but does that mean it exist?
Energy is not merely in our models and theories. It is also measurable.

Does your concept of “exist” allow for things that don’t “exist” to be measurable? If so, why should we care about it.
 
  • #17
  • #18
Dale said:
Energy is not merely in our models and theories. It is also measurable.

Does your concept of “exist” allow for things that don’t “exist” to be measurable? If so, why should we care about it.
right but if energy being measurable is enough to dictate that it exists then wouldn't there be a clear yes or no answer to the question
 
  • #19
@KleinMoretti: say you finally managed to decide whether it does or doesn't exist. Would that fact have any impact on your understanding of physics?

(A litmus test for filtering out questions that are probably a waste of time...)
 
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  • #20
KleinMoretti said:
right but if energy being measurable is enough to dictate that it exists then wouldn't there be a clear yes or no answer to the question
Yes.


We think it is a clear cut answer. Do you?
 
  • #21
Can't think of a significant difference between a (really good) model of reality and reality itself.
 
  • #22
DaveC426913 said:
Yes.


We think it is a clear cut answer. Do you?
well I dont know I do think it exists but I have also seen people say it's only a mathematical tool
 
  • #23
KleinMoretti said:
right but if energy being measurable is enough to dictate that it exists then wouldn't there be a clear yes or no answer to the question
Yes. If energy being measurable is enough to dictate that it exists then there is a clear yes answer to the question.

However, even if it is not enough to dictate that it exists, it is enough to refute the mischaracterization that energy is only part of our mathematical models.
 
  • #24
KleinMoretti said:
well I dont know I do think it exists but I have also seen people say it's only a mathematical tool
I think you have plenty to chew on to decide what answer satisfies you.

It's pretty much semantical anyway. The universe is happy to tick along - as it has since before the dinosaurs - whether or not we decide what it means for something like energy to "exist". It is what it is, regardless of our terminology.



I don't know who these people are who are tellng you it's "only" a mathematical tool, but consider this:

Mathematics lives in an abstract world; it cannot, itself, affect the physical world. Falling bowling balls are part of the real world and do real work. Things that are "only mathematical tools" can't make objects do real work.

So that "mathematical tool" is keeping careful track of something that actually exists of the real world and is having real effects on objects in the real world. Pretty hard to make an argument that that thing doesn't exist.

Finally: technically, this is a philosophical question. It has no true right or wrong answer. And technically, philosophical questions are outside the realm of science. And technically, philosophy is a subject outside the scope of PF. Ultimately, you've got to come to personal terms with an answer that makes you comfortable
 
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  • #25
KleinMoretti said:
well I dont know I do think it exists but I have also seen people say it's only a mathematical tool
Those people are clearly wrong. Things that are only a mathematical tool are not measurable.
 
  • #26
Dale said:
Things that are only a mathematical tool are not measurable.
"If you cannot measure it, you cannot manage it".
 
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  • #27
Also from the Feynman lectures quote I included in #1 I think Feynman himself didn’t think energy was a mere mathematics but I maybe misinterpreting it.
 
  • #28
When I lift a bowling ball, I invest energy in the process. The system configuration contains the energy, not the ball. When I dig a hole and make a pile of soil next to it, I am redistributing energy between the accounts of my system. If the ball is then lowered into the hole, the energy I invested on those two previous occasions flows on, between the state variable accounts of the system configuration.

Physics is a form of bookkeeping, that studies the fixed exchange rates between different forms of energy investment accounts. Energy is like a standard reference currency that has an inflation free, pegged value. There are no coins, promissory notes, or debts. I think I am correct in believing that, all transactions are by Electronic Funds Transfer.

Conservation of energy is simply, honest double-entry bookkeeping.
 
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  • #29
The OP question has been sufficiently addressed. Thread closed. (Thread also moved to Other Physics Topics as that seems to be the best place for it.)
 

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