What is energy?

[ThomasGR]

[Hu]

Energy is the ability to do work (force exerted over a distance).

W=ΔK=(K2-K1)

Work equals the change in kinetic energy of a system, which is the difference in the amount of kinetic energy a system has between its initial and final states. This difference is equal to the work done on the system.

W=F*s

The measure of force exerted over a distance is equal to the change in kinetic energy of a system, which is the work done on the system.

(The bold quantities are vectors).

[IreneY]

Hu I am pretty sure Θωμάς wasn't asking about the physics' definition . I think he asks "what is it exactly that thing that we call energy?" and I can't answer that exactly since there are different kind of "energies". I mean for instance kinetic energy is easily defined as a concept I think, others it's not as easy as that.

[Hu]

Um, that is the definition of energy. There are no "particles" of energy; you can't touch anything physical and call it "energy". Energy is just a concept that allows us to measure the amount of work a system can do (or that has been done on it). Although I'm naturally loath to quote Wikipedia on a matter of science, it seems to agree with my textbook:

Because forces are usually classified by kind (gravitational, electrostatic, etc), so are the specific forms of work they produce (or are involved in). For example, a gravitational potential energy is defined as the amount of work to elevate (or lower) a mass against a gravitational force; electrostatic energy is defined as the work done to rearrange electric charges against electric force, kinetic energy is defined as the amount of work to accelerate a body (against force of inertia) to a given velocity, etc.

Although I'm pretty sure I'm right, I'd feel more comfortable if someone more knowledgable in physics looked over this.

[IreneY]

Hu I am not saying that you are wrong. It's just that, as I interpret Thomas' post, I think we are asked something completely different, more philosophical than "pragmatic" if you wish.

[Hu]

Well as I see it, any definition of energy has to be scientific, since things like energy and work are scientific concepts. That's why I tried to explain that there are no "particles" of energy or the like, which I believe is what Thomas was asking about.

As for whether we've replaced the concept of "God" with "energy", I don't think so. People posited a "god" (I think this is what Thomas is implying) to explain certain things about their world. Science is much the same thing nowadays (although nobody prays to Newton or Maxwell or to the patron saint of impluse as the change in momentum).

I think Thomas is trying to ask if things like "God" or "energy" are just abstractions to help us understand the world that don't really mean anything where nature is concerned. If that's the case, I'd say they are very similar.

[Kopio]

Well as I see it, any definition of energy has to be scientific, since things like energy and work are scientific concepts.

They couldn't be metaphysical concepts also?? I'm not saying I have a metaphysical "definition per se, but I think that there could be a definition that is other than scientific. Of course, I'm a theist, so that seems far more possible to me than to my atheist friends.

As for whether we've replaced the concept of "God" with "energy", I don't think so. People posited a "god" (I think this is what Thomas is implying) to explain certain things about their world. Science is much the same thing nowadays (although nobody prays to Newton or Maxwell or to the patron saint of impluse as the change in momentum).

Ok, now that's just funny! That chuckle was well worth the price of admission Patron Saint of Impulse hahaha!

I think Thomas is trying to ask if things like "God" or "energy" are just abstractions to help us understand the world that don't really mean anything where nature is concerned. If that's the case, I'd say they are very similar.

I think you might be right. I know for me I think there is a kind of metaphysical "energy" that one wouldn't necessarily be able to quantify or measure...therefore it most certainly would be unscientific.

What do you think Hu? Are there other kinds of energy other than those which we can directly measure and quantify?

[ThomasGR]

[GlottalGreekGeek]

Well, any word is an abstract way of referring to something. For example, what is a carrot? I know what a carrot looks like, feels like, and tastes like. I know it is a vegetable which is the root of a plant and that orange light bounces off it because it has lots of beta carotene (aka Vitamin A), which also makes flamingos pink. However, I could not recognize a carrot's genetic code if you showed it to me, nor do I know enough about carrots that I could perfectly reconstruct one. If I talked to somebody who had never seen or been near a carrot, I could try to describe one, but it would only give the hearer a vague image.

I suppose the point I'm trying to say is, how deep an explanation of "energy" are you looking for, and could you give an example of a word/concept which you can define to the degree which you would like "energy" defined. Also, are you interested in "spiritual energy" (or other energies of that ilk), or merely the more physical kind?

[IreneY]

The way I see it we needed a term to name the "by doing this that happens".

For instance by turning a wheel like crazy electricity "happens". By rubbing two pieces of wood together fire "happens". Well, it's not magic! It's a doodah, a thingy. We actually found out we can measure how much doodah you need to make fire out of twirling a woof on another.

Since neither doodah or thingy are good definitions and the ancient greeks had that handly word around containing the word "work" with (among others) the meaning of a power that acts, brings about external results etc we used that one.

Anyone glorifying energy needs to get out in the fresh air more if you ask me

[Bert]

beta carotene (aka Vitamin A),

Not quite.

[ThomasGR]

Irene said: The way I see it we needed a term to name the "by doing this that happens".

For instance by turning a wheel like crazy electricity "happens". By rubbing two pieces of wood together fire "happens". Well, it's not magic! It's a doodah, a thingy. We actually found out we can measure how much doodah you need to make fire out of twirling a woof on another.

Since neither doodah or thingy are good definitions and the ancient greeks had that handly word around containing the word "work" with (among others) the meaning of a power that acts, brings about external results etc we used that one.

I wished it were that easy. Let us take nuclear physics. In nuclear fission we learn that atoms are split and energy gets freed. If we could count the remaining mass of our cubicle of Uranium, we would see that it’s less than before the fission. According to Einstein’s e=m*c^2, the missing mass has dissolved into energy. Mass dissolves into nothing? Into an abstract Idea, that we use only as a tool to explain our world? Again, in atomic fusion of Hydrogen, we put energy (OK, here energy stands for work and is easily understood) to make fusion happen and energy gets freed which is a surplus. We gain energy that has the ability to do work, out from nothing?

Irene said: Anyone glorifying energy needs to get out in the fresh air more if you ask me

Maybe this is the only explanation. Somewhere I read that God exist in the purest form of energy. As I do understand that: energy without mass (not the equation e=m*c^2). But than the question remains unanswered: what is energy? (For me, it is the same if I ask: what is God?)

[calvinist]

For instance by turning a wheel like crazy electricity "happens". By rubbing two pieces of wood together fire "happens".

Not to make this any more confusing but even cause and effect can be debated. For instance, how do we know that rubbing two pieces of wood together "causes" fire. We only know that after the one thing happens the other happens in successive order in what we call time. Even from a more scientific point of view and trying to describe what exactly "causes" fire we still ultimately come to this. I think it was David Hume who was the first to talk about this difficulty in understanding "cause and effect". Just another one of those things we all understand but get lost when we try to describe or explain it; like energy, time, etc.

[ThomasGR]

[Amadeus]

They couldn't be metaphysical concepts also?? I'm not saying I have a metaphysical "definition per se, but I think that there could be a definition that is other than scientific. [...] I know for me I think there is a kind of metaphysical "energy" that one wouldn't necessarily be able to quantify or measure...therefore it most certainly would be unscientific.

May I offer a few corrections?

Metaphysics is a part of Philosophy and, ideo, a branch of science. People have this idea that Philosophy is not science (only an elaborate opinion), but it most certainly is, it is the mother (basis) of all sciences, as it tries to explain everything (I repeat, e-v-e-r-y-t-h-i-n-g) with the light of reason. Remember also, there are "pure" sciences and "empirical" sciences, both are valid.

Not to make this any more confusing but even cause and effect can be debated. For instance, how do we know that rubbing two pieces of wood together "causes" fire. We only know that after the one thing happens the other happens in successive order in what we call time.

David Hume's empiricism is totally insane. The mind is capable of perceiving the inner laws of objects; else, if his assertions were correct, no science would be possible, quod absurdum.

[Kopio]

May I offer a few corrections?

You may always offer me corrections. Especially in this forum...Philosophy has never been my strong suit. I welcome your input.

Metaphysics is a part of Philosophy and, ideo, a branch of science. People have this idea that Philosophy is not science (only an elaborate opinion), but it most certainly is, it is the mother (basis) of all sciences, as it tries to explain everything (I repeat, e-v-e-r-y-t-h-i-n-g) with the light of reason. Remember also, there are "pure" sciences and "empirical" sciences, both are valid.

I guess I've been to influenced by all of the stuff I've been reading on Atheism and Naturalism. In those views the metaphysical seems to be, for lack of a better word, absurd. If you can't see it, touch it, test it, verify it, it simply doesn't exist. Not that I believe that, but I have been trying to have a more "rational" approach to my thinking lately. That being said, I am a person who operates by Faith in a God that can't be seen or touched. But for me, faith isn't necessarily a "rational" choice, it is a "faith choice. Does that make sense?

Also...empirical sciences would be science that we can theorize about, test, observe, and draw conclusions based upon our observations. It is a repeatable event that we can watch and learn from. Am I right here? What then is pure science? I don't know if I've ran across that terminology before (as you groan while you read this please remember that I am a Greek and Theology Major) can you 'splain it to me?

[TADW_Elessar]

The surplus energy will than be emitted in the form of photons. So, we have here pure energy in the form of particles (or waves?)

Well, we don't have "energy" in the form of photons (which, like electrons, are not very small balls nor waves). We have photons which carry energy.

Mass dissolves into nothing? Into an abstract Idea, that we use only as a tool to explain our world? Again, in atomic fusion of Hydrogen, we put energy (OK, here energy stands for work and is easily understood) to make fusion happen and energy gets freed which is a surplus. We gain energy that has the ability to do work, out from nothing?

From nothing? It comes from matter. Einstein's most famous equation states that matter and energy can be changed one into the other.
We are able to produce matter (and anti-matter) from energy, and to make energy out of matter.

We can't see energy. But this doesn't mean it doesn't exist.

As for the relationship between energy and God, I think the theme is way too much above my possibilities and my knowledge.

[Amadeus]

I guess I've been to influenced by all of the stuff I've been reading on Atheism and Naturalism. In those views the metaphysical seems to be, for lack of a better word, absurd.

Yes, after Descartes, there is a tendency in philosophers to deny metaphysics (and, in Hume's case, science). You should read about aristotelianism or scholasticism to get a more balanced view on theoretical philosophy.

If you can't see it, touch it, test it, verify it, it simply doesn't exist. Not that I believe that, but I have been trying to have a more "rational" approach to my thinking lately.

Well, metaphysics is rational. People, as I said, mistakenly view it as mere opinion (or in the case of my mother, as the occult ), because it does not follow the "scientific" method and its propositions are not open to empirical falsification. But the "scientific" method is not the only criteria for knowledge, there is another: rational argumentation. Mathematics uses rational argumentation to creat and correct theorems, and so forth. Is mathematics mere opinion? No, it is knowledge, and so is Metaphysics.

What then is pure science? I don't know if I've ran across that terminology before (as you groan while you read this please remember that I am a Greek and Theology Major) can you 'splain it to me?

Pure science is "theoretical science" or science that requires little or no special empirical evidence, like mathematics, theoretical physics, ontology (metaphysics), natural theology et cetera.

Anyway, thanks for your reply. It's been a while since I read anything about philosophy. Oooh, I can't wait to start college (that is, if I get accepted), and study what is my passion, my life.

Vale atque valete!

[TADW_Elessar]

Is mathematics mere opinion? No, it is knowledge, and so is Metaphysics.

I'm not sure Immanuel Kant would agree on this particular point

[Amadeus]

I'm not sure Immanuel Kant would agree on this particular point

I'm sure he wouldn't agree with me. Luckily he was wrong.

[IreneY]

People who talk about mathematics as being so rational and so on and so forth forget to take into account that there is no such thing as minus 1 in nature. I am not talking about substraction I am talking about e.g. the temperature falling below zero. Below nothing? (there are other examples of how theoretical the science of maths is but that's one of the simplest examples I could think of).

There are also the ones called hard sciences and physics is one of them. You see, you measure, you experiment, you state. If only things were so simple! I wouldn't have such troubly in physics as a student since I am good at seeing and stating what I see and understanding concepts and definitions that are based on such a procedure.


I am not denying that the world is acting in a certain way blah blah blah yadda yadda yadda. After all I am an atheist and that, by default, means that I don't believe that some higher power is making things happen. However there are things that we don't fully grasp or don't grasp at all. We fumble with the explanations and come up with purely theoretical ways to describe certain actions. We then call this descriptions "the truth" and wait till someone comes around to tell us it's a lie.

BY the way, can anyone understand and explain to me the "the cat in the box is either dead or alive and its state of "health" will be determined by us opening the box" thingy? It seems
a) either too anthropo/egocentric (the cat is either alive or dead whether you know it or not buddy!)
b) a bit too .. philosophical , of the "does the falling tree make any sound if no one's there to hear it" kind (yeap it does but the question is philosophical so physics can go hang as far as it's concerned)

Edit: Just realised that it's "does anyone understand and can explain". Proficiency of Cambridge in English my foot!
GGG thanks! Now I have some more info! We're getting there!

[GlottalGreekGeek]

BY the way, can anyone understand and explain to me the "the cat in the box is either dead or alive and its state of "health" will be determined by us opening the box" thingy? It seems
a) either too anthropo/egocentric (the cat is either alive or dead whether you know it or not buddy!)
b) a bit too .. philosophical , of the "does the falling tree make any sound if no one's there to hear it" kind (yeap it does but the question is philosophical so physics can go hang as far as it's concerned)

Ah, Schrondinger's cat (or however you spell his name)

When I first heard about it, I had the same reaction as you - the cat is alive or it is dead, it's not half-alive half-dead. I do not fully understand it myself, however I dimly recall that it is a way to illustrate a key concept required for understanding quantum physics, and the life/death of an animal is more memorable than, say, whether the paper inside the box is black or white. I may be totally wrong about this.

[Tyro]

BY the way, can anyone understand and explain to me the "the cat in the box is either dead or alive and its state of "health" will be determined by us opening the box" thingy? It seems
a) either too anthropo/egocentric (the cat is either alive or dead whether you know it or not buddy!)
b) a bit too .. philosophical , of the "does the falling tree make any sound if no one's there to hear it" kind (yeap it does but the question is philosophical so physics can go hang as far as it's concerned)

I don't boast to understand but what I heard about it is that this "experiment" is used lift a purely Quantum Mechanical effect into our everyday's world. As it seems, theoretically and experimentally, small particles stop to exhibit well-defined states (location, energy e.g.) but take certain values of these properties with a certain probality. To force the particles to do this, one must measure the respective property.
So Schroedinger's cat, whose life thread depends on a Quantum Mechanical property, is neither dead nor alive as long as no one checks.

People who talk about mathematics as being so rational and so on and so forth forget to take into account that there is no such thing as minus 1 in nature. I am not talking about substraction I am talking about e.g. the temperature falling below zero. Below nothing? (there are other examples of how theoretical the science of maths is but that's one of the simplest examples I could think of).

I should thank God that Math has nothing to do with real life and in the spirit of this I would like to speak on the behalf of our poor zero in that its "nothingness" is nothing mysterious or a lower bound beyond which lies chaos: The number one shows the same behaviour as zero, namely to leave elements invariant if applied, yet no one is mystyfied by that.
However, Dedekind said something like that God made the naturals while the rest was made by man.

Generally, I wouldn't like to make a distinction between physics or philosophy.

[ThomasGR]

[ThomasGR]

People who talk about mathematics as being so rational and so on and so forth forget to take into account that there is no such thing as minus 1 in nature.

My favorite example for that is straight line. In nature, there are no things like streight lines, square surfaces and cubic rocks.

[TADW_Elessar]

We have produced matter from energy?

Sure. If a high energy photon (at least 1022 MeV to produce an electron - positron pair) collides with an atomic nucleus, its momentum is conserved and a particle+antiparticle pair is created. Since total momentum is conserved, the electric charge and other quantum numbers of the two particles must be opposite (i.e. one electron and one positron, one proton and one antiproton etc.), so that they sum to 0.
This was first observed in the mid 20th century.

[Amadeus]

People who talk about mathematics as being so rational and so on and so forth forget to take into account that there is no such thing as minus 1 in nature.

My favorite example for that is straight line. In nature, there are no things like streight lines, square surfaces and cubic rocks.

Uh, no.

Rational is that which can be conceived in the mind. -1 or a straight line may not be found in nature, but we can think them, and that's what makes them rational.

[ThomasGR]

That means nature is not rational. Than why do we try to understand nautre having as our only helper rationality? Energy began as a rational concept, or a tool if you prefer, that existed only inside our (limited?) minds, and suddenly we can even produre matter out of it, even if we don't know what's energy. It looks our mind can manipulate reality.

[TADW_Elessar]

It looks our mind can manipulate reality.

I prefer to say that our mind can go well beyond what we can sentire or experiri (so to speak). But, with time, our "rational" concepts may prove to be right in a more evident way (this is the case of Einstein's relativity, which was first "observed" during an eclypse, or energy, which was introduced during the 18th century as vis viva, if I remember correctly).

[IreneY]

a) Rational's definition as whatever can be coneived in the mind is partial and only one of the definitions possible.

b) If you think of rational as something that is based in reason as I did when I used this word then in nature nothing can be "below zero". I am not talking about how things behave in theoretical maths, I am talking about nature. In nature at least, zero temperature and temperature of 1 don't leave elements invariable do they? Not both of them at least

c) As for the cat, thanks Tyro but I still don't get it. I can't say that I understand what I've read about quantum mechanics but I still don't get the cat example Bad example/parallelism maybe?

d) Rational concepts may prove wrong too.

[Amadeus]

After finding a little time outside of work, and a lot of head-banging on the wall, here's another attempt at this tangled web (which I helped create):

People who talk about mathematics as being so rational and so on and so forth forget to take into account that there is no such thing as minus 1 in nature. I am not talking about substraction I am talking about e.g. the temperature falling below zero. Below nothing? (there are other examples of how theoretical the science of maths is but that's one of the simplest examples I could think of).

Degrees are a conventional, relative form of measuring temperature; water's boiling and freezing points were assigned the numbers 100 and 0 respectively. Minus 1 is not below nothing, but below water's assigned 0, its freezing temperature. I see nothing complicated or irrational about that.

There's another zero in relation to temperature, namely: Absolute zero, which is the lowest temperature imaginable, as all movement of particles and all friction has stopped. It isn't found in nature and scientists have not been able to produce it, but it is intelligible.

If you think of rational as something that is based in reason as I did when I used this word then in nature nothing can be "below zero".

My mistake. What can be conceived in the mind cannot be rational or irrational, only intelligible or inintelligible. Rationality comes afteward. Still, I don't really get your point. 0 Celsius is just a point of reference, it doesn't mean "nothing".

Energy began as a rational concept, or a tool if you prefer, that existed only inside our (limited?) minds, and suddenly we can even produre matter out of it, even if we don't know what's energy. It looks our mind can manipulate reality.

You have to distinguish between 1) Energy, as the "thing", the reality found in the universe, and 2) Energy, as a concept formed by the mind from other ideas (such as force). Energy (1) was already in the universe before we understood what it was (2) and gave it a name. We did not invent it. How do we know we have understood it? Because we can manipulate it.

Valete!

[ethopoeia]

[ThomasGR]

[cdm2003]

c) As for the cat, thanks Tyro but I still don't get it. I can't say that I understand what I've read about quantum mechanics but I still don't get the cat example Bad example/parallelism maybe?

It took me quite a while to get the cat thing...I understood it in different terms:

Imagine (instead of the horrifying prospect of dumping poison, uranium, and a live cat into a box and taping it shut ) that you have a simple voting booth. Inside the voting booth is a single switch with which people choose a new victor. One side of the switch says "John" and the other side says "George." In the back of the simple voting machine is a small computer with a single red button which will automatically tally the results and spit out a little piece of paper with the name of the winner when the button is pressed. Now, you're a voting official. Your job is to make sure that people can vote undisturbed and confidentially. At the end of the day, it's also your job to push that button to get the paper with name of the winner. There's no trick to this example...no tampering, no mysterious workings of the computer, just straight-forward voting.

People come in and out all day long and vote for either "John" or "George." As an objective voting official, you keep the peace and certainly do not ask anyone who they are voting for when they enter the booth nor do you ask them who they voted for when they leave. Your day ends and it's time to push that button and tell the reporter next to you who won the election. You head to the little computer and push the red button. Out comes the slip of paper...but oh snap! In your haste to get things ready for the day's election you forgot to check the ink cartridge inside of the machine! The paper containing the name of the official winner is blank!

Schroedinger's poor abused cat is in the same situation as this election. Now, the election result does not depend upon a quantum event like the cat. However, like Schroedinger's cat, the election result does depend on a statistical result, which, in this case, is the number of votes for "John" weighed against the number of votes for "George." Schroedinger's cat, inside of the box, has a 50% chance of being alive. In this election, both "John" and "George" have a 50% chance of being the winner (i.e., there were only two possible outcomes). Now, that reporter that was standing next to you is demanding the result. He says that his readers must know immediately who won! You know someone won...after all, the computer did it's job...you just don't know who won...as the sheet is devoid of ink. That's Schroedinger's rub...someone actually did win this election, some people actually voted for "John," some for "George." However, because of the statistical uncertainty (that 50/50 chance for either candidate) you have no idea. Technically, election day is over. People did vote...people did choose...votes were tallied. Only the election is in bizarre state of uncertainty and not because anything out-of-the-ordinary happened during the election. It is because the election results hinged on a statistical result which, all things being equal, gave each of the two candidates a 50% chance of winning.

As the vitality of Schroedinger's cat is unknown until we open the box, so too will remain uncertain the results of our election, at least until we pop in a new ink cartridge and finally find out who's the better backup singer for the Beatles.

Quantum mechanics offer the same sort of statistical uncertainties. We don't know if an electron is here or there but we know it is one of the two places. We could guess it's here, but by the time we look to be certain it's over there, or worse yet, our looking has bumped it over to there. Then, we look over there to see it, but it's now it's moved back to here. It's too small and too fast to grab on to to check, so we're forever guessing. Wild, huh?

Hope this helps,
Chris

[Amadeus]

ThomasGR,

I was going to reply at length to your post when I realized that I don't get what your point is. If science doesn't give you a satisfactory definition of energy, then... what? Is it your contention that energy does not exist or that science is not rational?

Apologies, maybe I'm just a little obtuse.

[IreneY]

cdm 2003 thanks!

It clears things up a bit although I still have objections with the example which probably means I haven't got it.

Now let's see if I am capable of making myself understood on a matter I don't really understand that well (given my history in making myself understood in general I bet it'll be a complete and utter failure but oh well!)

We've got these particles who we can make change position or whatver by just looking at them so to speak. OK, I don't really get it (the mechanism I mean) but I think I understand the concept.
Now let's take the cat. The cat is slightly bigger and more complex than a particle. I know I can't make a cat move just by looking at her. Heck, at times I can't make my cat move even when I yell at her to although just making as if I'm going to start hoovering the place works wonders.

Now let's say that cat inna box is dead. How would my looking at her make her live again? She's dead and that's it. The only thing different in the world is that I don't know about it and therefore, after I find out my perception of the world will have to change and will include a dead cat instead of having a question mark as far as its state of health is concerned.

The cat is dead or alive and there's nothing I can do to change it unless it's alive and I let her out of the damn box and give her some help after being scratched almost to oblivion if she's up to it (if not she'll save it up for later, trust me).

[Democritus]

I don’t think this is always the case. We can do lot of things, without having a clue what’s going on. My preferable example for this case is electricity. What’s electricity? Like energy, we don’t know. It’s just there and we can measure it, calculate its effects. We see the difference of an electron and its counterpart the positron, but what’s making the difference?

This might be interesting for you: http://www.fotuva.org/feynman/what_is_science.html

[Arvid]

This thread seems to have petered out a while ago, but it is an interesting question, so I thought I'd throw in my two cents.

First of all, Erwin Schrödinger intended the cat scenario as a reductio ad absurdum, but so many people have taken it seriously that Stephen Hawking was moved to paraphrase Hermann Göring and say: "Whenever I hear of Schrödinger's cat, I reach for my gun!" The orthodox interpretation of quantum mechanics is unfortunately Bohr's mystical mumbo-jumbo about the "collapse of the wave function" of a quantum object being dependent on measurement by an "observer." The decay of the nucleus that triggers the mechanism that delivers the poison with 50% probability during the time interval in question is a quantum event, that is, completely random. Therefore, until we "measure" the outcome of the experiment, the state of the system is in a "superposition" of the two states. In this case, though, there's a macroscopic object that's entangled with the outcome of this quantum process: the cat. Is the cat in a superposition of two states, alive and dead, until we open the box to find out? Schrödinger thought this was ridiculous, and so do I. Why is the cat not a good enough "observer" anyway?

As for what energy "is," that's a little harder question. Operationally, what it is is a conserved quantity. The histories make you think that energy was something we discovered and then later found out to stay the same in every reaction and transformation it underwent. Really, we found a mathematical quantity that stayed the same in every reaction and labeled it "energy."

Fundamentally, Noether's Theorem tells us that to every symmetry we discover of space and time, there corresponds a conserved quantity. Space is homogeneous, it doesn't change from place to place: therefore momentum is conserved. Space is isotropic, the same in every direction: therefore angular momentum is conserved. And, since time flows homogeneously, therefore energy is conserved. To say one is the same as saying the other. So if we ever find some process where energy is not conserved, we will have demonstrated that time doesn't always flow homogeneously, a pretty radical conclusion from the measuring of a quantity that we can't even define!

[petka]

Of course, energy is a philosophical term and consecrated by Aristotle metaphysics. His intuition of the term was quite great since it meets such philosophers as Thomas Aquinas and especially Palamas/ But I think his definition of energy is that: activity, simply activity, any kind of activity. The latin translation was actus purus. No matter if we are referring to it in any kind of science or metascience, either physics or metaphysics. It is activity, or in Christian philosophical understanding is any kind of "operation". What Aristotle did wrong in its definition of energy is that he tended to confuse, if I remember well, the godhead, the divine with energeia. Christian thinkers who dealt with this matter of energeia st. John of Damascus, st. Gregory Palamas define energy rather as separated of nature, but as an active emanation of nature and also an attribute of the nature by which nature manifests itself as active and actual. Somebody used the term kynetic energeia, though kinesis in itself is an energeia. but this shows exactly what happened within the divine plane. It is the kinesis of the divine nature beyond itself to manifest itself in diferent hypostases : that of Creator of the universe, goodness, kindness, mercifulness, forgiveness are also energies by which the absolute transcendent divinity makes itself manifest within the world. Another term which the energy combines well is dynamis. In Aristotelic sense these two terms are in a slight opposition, because, there, the energeia as activity is something actual, something that really happens, really "works" and acts. Mind is such a self-subsistent energy. While dynamis is quite different because it implies something that could be, but it is not yet happened, so it is not actual but virtual, dynamis is in potentia, as a promise which awaits the entelecheia of the energy to become actus, activity from virtuality to actuality. In Christian thought these terms are rather synonims . The energies, because they are different, are the way by which God communicates with the created world, the way He manifests in the world, the way He works in the world, intereferes in time and space while remaning totally transcendent, uncircumscribed (aperigraptos) temporally or spatially in His nature, because the nature, to on is acategorial. That is why the uncreated energies are any "kynetic" activity of God manifested in time and space, but they are not self subsistent so they are not enhypostasiated that is to say they don't exist in a hypostasis being just a radiance of nature. It belongs to it essentially but without confounding with essence, nature, it is uncreated and also it has all the characteristics of divinity without confounding with the divine nature, because they exist in time when they manifest in time, but there is not a moment when nature existed without energy, because if we light a fire in the same time that fire manifest as fire, heat and light appear all the same. and they could not exist or rather subsist independently of fire but they are an emanation a result of the activity of fire. As the sun could not ever appear without its rays, without stopping to be sun. As for the mind itself it never stop thinking in that sense it is energy, pure energy, but the effect of its activity is the thought. the thought exists as a manifestation of the mind as an energeia not as actus purus, because it is not self subsistent as the mind is.

[Kyneto Valesio]

Wow Petka I am really amazed at the depth and insight of your post from December which I have just gotten around to partially digesting. Of Aristotle I know nothing yet I can't help agreeing -if I understood you correctly -- that philosophically there must be a distinction between the godhead and his manifold energies. You wrote

What Aristotle did wrong in its definition of energy is that he tended to confuse, if I remember well, the godhead, the divine with energeia.

If the godhead is the source of all energy then there is a logical distinction between the "energetic" and his/its energies as manifested in material nature and also in the hearts of man. By way of analogy (imperfect of course) the godhead can be thoughout of as the powerplant (the energetic) which is distinct from the electricity in the transmission lines. Another analogy (also imperfect) might be found in the sun and rays of the sun. The rays are not the sun yet they have their origin in the sun. So by analogy (so it seems to me) there must be a distinction between the godhead and his activities so to speak. On the other hand since the godhead is absolutely the origin of everything, everthing including all of the godhead's manifestations must in some reduced degree participate in the godhead. If the human soul is considered to be "an energy" of the godhead, which i believe, then we also are divine as having our origin in the divine - but we cannot then go around claiming that we are the godhead because of distinction outlined above, because we are not the original source of all manifestations ourselves. To summarize my view, which i have adapted from the the vaishnava philosphers of bengal, whose erudition on these matters I follow, the godhead and his energies are inconceivably one and different. I myself am not a philosopher like you so obviously are petka. Nevertheless I hope I have been able to have been understood by you.

I am not unaware that I owe you a response concerning your hymn written on the occasion of the nativity (posted in the composition section). Please accept my apologies for the delay. I will work up something soon. In the meantime please post more often. Yours Cynetus Valesius