Entities and attributes in science

Discussion in 'General Philosophy' started by James R, Mar 23, 2023.

  1. James R Just this guy, you know? Staff Member

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    Write4U:
    You need to let go of this idea that energy is like a substance that can be contained in things, or that things can be made of energy. Energy is just a number, an accounting system. There is no energy inherent in anything. Energy is just a number (or a set of numbers with different labels) that we can calculate for a system.
    Nothing is needed.

    Newton's first law of motion: a particle that is not acted on by any force will travel at constant speed in a straight line.

    Nothing is needed to keep something moving in a straight line at constant speed. Things just do that, all by themselves, without needing anything to push them around.
    No energy is needed, let alone an infinite energy. A constant input of energy is not needed to keep an object moving at constant speed.
    No. For it to have infinite energy it would need to be inside the walls of the box. The infinitely strong force prevents that from ever happening, in the simple model of the particle in the box. Between the walls, the potential energy is zero, so particle has a finite amount of energy, equal to its kinetic energy, which doesn't change.
    Well, maybe, but it's impossible to get any useful work out of an "empty" cubic centimeter of space.* So, even if that's true, in practical terms it doesn't seem to matter very much.

    ---
    (* The Casimir effect might complicate this statement a bit.)
     
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  3. arfa brane call me arf Valued Senior Member

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    You need to ah, inflect this with what Richard Feynman also said about energy (as well), and how we use it like an accounting system; what he said was, to paraphrase, "We count units of energy and use the result successfully, to predict the outcomes of experiments (he means it doesn't matter what energy is). He also said nobody 'really' understands what it is, but we count units of it despite this awful truth.

    They have a name, Joules, and Joules have physical units. It isn't or shouldn't be any surprise that they have some physical mathematics in there as well, and also. You can substitute electron-volts but they have the same units. What you call a physical unit doesn't change what it is Duh.
     
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  5. James R Just this guy, you know? Staff Member

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    arfa brane:

    I'm a big Feynman fan, but if he actually said nobody really understands what energy is, then I'm inclined to disagree. It sounds to a lot like he had a pretty good understanding about what energy is.

    I have at no point said that there is no mathematics about energy. Clearly, it's all about mathematics. And yes, energy has some physical units. So what?
     
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  7. arfa brane call me arf Valued Senior Member

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    Ok, so what was it Feynman actually said; how did I not paraphrase him according to you?
    Are we going down the same rabbit hole all over again? I'd better remember to take the blue pill, huh?
    So saying energy is just a number isn't quite true is it? Physical units are not numbers. If Feynman said something about knowing or understanding what something is, did he contradict himself by also saying he doesn't know and nor does anyone?
    Or is it just you?
     
  8. exchemist Valued Senior Member

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    Here is what Feynman had to say about energy in one of his lectures (extract from this: https://www.feynmanlectures.caltech.edu/I_04.html) I have highlighted what seem to me key passages in red.

    QUOTE

    In this chapter, we begin our more detailed study of the different aspects of physics, having finished our description of things in general. To illustrate the ideas and the kind of reasoning that might be used in theoretical physics, we shall now examine one of the most basic laws of physics, the conservation of energy.

    There is a fact, or if you wish, a law, governing all natural phenomena that are known to date. There is no known exception to this law—it is exact so far as we know. The law is called the conservation of energy. It states that there is a certain quantity, which we call energy, that does not change in the manifold changes which nature undergoes. That is a most abstract idea, because it is a mathematical principle; it says that there is a numerical quantity which does not change when something happens. It is not a description of a mechanism, or anything concrete; it is just a strange fact that we can calculate some number and when we finish watching nature go through her tricks and calculate the number again, it is the same. (Something like the bishop on a red square, and after a number of moves—details unknown—it is still on some red square. It is a law of this nature.) Since it is an abstract idea, we shall illustrate the meaning of it by an analogy.

    Imagine a child, perhaps “Dennis the Menace,” who has blocks which are absolutely indestructible, and cannot be divided into pieces. Each is the same as the other. Let us suppose that he has 28 blocks. His mother puts him with his 28 blocks into a room at the beginning of the day. At the end of the day, being curious, she counts the blocks very carefully, and discovers a phenomenal law—no matter what he does with the blocks, there are always 28 remaining! This continues for a number of days, until one day there are only 27 blocks, but a little investigating shows that there is one under the rug—she must look everywhere to be sure that the number of blocks has not changed. One day, however, the number appears to change—there are only 26 blocks. Careful investigation indicates that the window was open, and upon looking outside, the other two blocks are found. Another day, careful count indicates that there are 30 blocks! This causes considerable consternation, until it is realized that Bruce came to visit, bringing his blocks with him, and he left a few at Dennis’ house. After she has disposed of the extra blocks, she closes the window, does not let Bruce in, and then everything is going along all right, until one time she counts and finds only 25 blocks. However, there is a box in the room, a toy box, and the mother goes to open the toy box, but the boy says “No, do not open my toy box,” and screams. Mother is not allowed to open the toy box. Being extremely curious, and somewhat ingenious, she invents a scheme! She knows that a block weighs three ounces, so she weighs the box at a time when she sees 28 blocks, and it weighs 16 ounces. The next time she wishes to check, she weighs the box again, subtracts sixteen ounces and divides by three. She discovers the following:

    (number ofblocks seen)+(weight of box)−16 ounces3 ounces=constant.(4.1)
    There then appear to be some new deviations, but careful study indicates that the dirty water in the bathtub is changing its level. The child is throwing blocks into the water, and she cannot see them because it is so dirty, but she can find out how many blocks are in the water by adding another term to her formula. Since the original height of the water was 6 inches and each block raises the water a quarter of an inch, this new formula would be:
    (number ofblocks seen)+(weight of box)−16 ounces3 ounces+(height of water)−6 inches1/4 inch=constant.(4.2)
    In the gradual increase in the complexity of her world, she finds a whole series of terms representing ways of calculating how many blocks are in places where she is not allowed to look. As a result, she finds a complex formula, a quantity which has to be computed, which always stays the same in her situation.


    What is the analogy of this to the conservation of energy? The most remarkable aspect that must be abstracted from this picture is that there are no blocks. Take away the first terms in (4.1) and (4.2) and we find ourselves calculating more or less abstract things. The analogy has the following points. First, when we are calculating the energy, sometimes some of it leaves the system and goes away, or sometimes some comes in. In order to verify the conservation of energy, we must be careful that we have not put any in or taken any out. Second, the energy has a large number of different forms, and there is a formula for each one. These are: gravitational energy, kinetic energy, heat energy, elastic energy, electrical energy, chemical energy, radiant energy, nuclear energy, mass energy. If we total up the formulas for each of these contributions, it will not change except for energy going in and out.

    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. It is not that way. However, there are formulas for calculating some numerical quantity, and when we add it all together it gives “28”—always the same number. It is an abstract thing in that it does not tell us the mechanism or the reasons for the various formulas.

    UNQUOTE

    In summary, it's not stuff with its own existence, it's a numerical quantity that is useful in calculations concerning physical systems.
     
    Last edited: Mar 24, 2023
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  9. arfa brane call me arf Valued Senior Member

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    And it doesn't matter in those calculations that despite "no knowledge of what energy is", we can calculate it and call it a numerical quantity, although doing so should not imply that we know what it is. Otherwise you clearly also have a contradiction.

    Or do we cast logic aside with this?
    I just can't get past energy being a number but we have no knowledge of what this number is. A number is a very simple thing, a well-understood thing, something that we do know and understand what it is.
     
  10. Write4U Valued Senior Member

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    That is why I identify these things as "relational values" and "mathematical functions". It's generic.
     
  11. arfa brane call me arf Valued Senior Member

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    My take on what Feynman was talking about:

    I note the man also makes a distinction between knowing and understanding. In physics, understanding a thing, such as energy or entropy, involves the use of formulas, it means you can manipulate the thing mathematically and so have a level of understanding which is based on numerical thinking.

    But you don't have knowledge, you don't get that from mathematics because it doesn't tell you what things are, only how they're mathematically related.

    So that's what he meant when he said nobody knows what energy is; that doesn't mean nobody understands how to "use" it.

    He is also kind of saying, don't start thinking that physics is a done subject; there are lots of questions nobody knows the answers to.

    p.s. in the above quote from Feynman, notice he fails to say when he is talking in a mathematical context and when he talks about the physics. That's quite common in physics though, to unconsciously equate laws of physics with mathematical formulas. A good student shouldn't get too fazed.
     
    Last edited: Mar 25, 2023
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  12. James R Just this guy, you know? Staff Member

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    arfa brane:
    Unfortunately, the time is past for taking up your issue with Feynman himself.

    To me, Feynman's statement is pretty clear, in the context in which it appears, helpfully posted by exchemist, above. For whatever reason, you still seem to have some kind of mental block that prevents you from understanding Feynman's point. I think that's your issue, not mine or Feynman's, but I'm sure you'll continue to believe otherwise.
     
  13. exchemist Valued Senior Member

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    In fact, the passage I quoted could be taken to apply equally to another numerical quantity that we all seem to use perfectly happily without anyone getting any misconceptions about it: momentum.

    Nobody tries to argue momentum is "stuff", that has an existence independent of a particular physical system. Everyone is happy that, seeing as it is just mass x velocity (usually), it is only a derived number that is conserved and therefore useful. So why the false mystique about energy?
     
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  14. arfa brane call me arf Valued Senior Member

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    To you it's pretty clear. But you can't explain what he meant when he said what he said. You want to live in a world that pats you on the back for being such a clever prick, But you're just a prick.

    A rather ignorant and self aggrandizing sort of prick. You might try not being such an Australian about everything. Try to imagine there are other places in the world where people don't think like you, at all.

    I did explain what I thought Feynman meant. Physics is theoretical and the mathematics doesn't tell you what physical units are. Physics is also experimental, but that doesn't tell you what physical units are either. No one really knows what physical units "really" are, or at least, physics doesn't.

    You can't see past your little worldview, It's sort of sad I guess. But since you're such a prick, it sort of doesn't matter really.

    Why are you still here? Is it to impress people? It isn't working.
     
  15. arfa brane call me arf Valued Senior Member

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    Right. But you don't have any misconceptions about it do you?

    Apart from that one about being able to explain what physical things really are. You're just as ignorant as everyone else about that and you prefer to believe you aren't. That's a pretty big misconception.
     
  16. James R Just this guy, you know? Staff Member

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    What does anybody mean when they say something? I guess, if you want to get all philosophical about it, words that people say can have many different possible intended meanings, as well as many different possible understood meanings.

    I can certainly explain what I understand Feynman to be saying. Can you?
    Because I understand something you're struggling mightily with? That makes me a prick, does it?

    I think your real issue is that you've discovered a situation where you're suddenly finding you're not the smartest person in the room, like you assumed you were. Your ego took a hit and now you want to blame somebody else.

    Really, get over it. It's not the end of the world. You should rightly be thanking me for helping to improve your understanding, rather than calling me names like a middle-school kid.
    Very clever, arfa brane. Congratulations. I see what you did there, making a point of insulting Australians in general. Does that make you feel like the bigger man?
    Those units that you claim nobody understands are defined, as far as I'm aware - or else derived from other defined units. What's the problem?
    We all have our limitations, it seems. What makes you think my worldview is little? Anything specific? I'm really interested to find out. .... Well, no, actually. I don't really care. It's unlikely I'll learn anything useful from somebody who has given up on civility, other than more reasons to avoid engaging with that person.
    Bah bowm! My intention is not primarily to impress people.

    Why I am here is on the record in other threads/posts, I am confident. I'm not especially motivated to respond specially to that question, coming from you. Go find out for yourself, if you're really interested. Maybe we can chat again after you've learned some manners.
     
  17. arfa brane call me arf Valued Senior Member

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    James R pivoted from the subject of--wait for it--what Feynman said, to attacking me.

    He has said nothing substantial about what the "great man" had to say, beyond polishing his own badge of honor.

    Fuck that. And fuck the lot of you pack of ignorant shitheads.
     
  18. James R Just this guy, you know? Staff Member

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    Now, now. Let's not try to rewrite history here.

    You introduced Feynman into this discussion in post #15. You addressed that post specifically to me, in response to something else I wrote to someone else.

    In your post #20, we discovered that you weren't aware of what Feynman said on the subject of energy. Nevertheless, you essentially insisted that what Feynman said was wrong.

    In post #21, exchemist helpfully provided the relevant section from the Feynman lectures.

    In post #24 you told us all "[your] take on what Feynman was talking about", and you told us all where you think Feynman failed to get it right.

    In post #25, I noted that, if your argument is with what Feynman said, it is too late to argue it out with him now. I also noted that my understanding of Feynman's words is different from yours.

    Post #27 is where the "pivoting" into a personal attack happened. And who started that? Why, fancy that! It was you again. Having completely run out of arguments, apparently, you decided to try ad hominem.

    Unfortunately for you, you just made yourself look like a dick again.

    And now, here you are, still being a dick. Only now, you're doubling down with the lies as well.
    When you've got nothing to say, throw a hissy fit and swear a lot. That'll earn you heaps of credibility, no doubt. Oh, wait...
     
  19. arfa brane call me arf Valued Senior Member

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    This is what's wrong with you, and with trying to communicate with you about anything.
    "You discovered" that I wasn't aware of yada yada; bullshit you lying prick.
    I did not tell you all where I think Feynman failed to "get it right"; that's all in your head you narcissistic piece of shit. Fuck you.

    You are probably the main reason people just give up on this piece of shit site. Keep having all the fun, ok? I've probably lost interest, but I seem to have to remind myself about that. Fuck what a moron you are.
     
  20. arfa brane call me arf Valued Senior Member

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    7,832
    And stop fucking talking to yourself, you fucking narcissist.
     
  21. arfa brane call me arf Valued Senior Member

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    But is momentum "really" just a numerical quantity? That's all mathematics has to say about any calculation, isn't it?
    Nobody tries to argue that momentum is just a number in an equation, do they (apart perhaps from James R)? Nobody tries to argue that they know how momentum is conserved beyond observing things in motion, about which mathematics says, well, nothing at all. Mathematics says things about numbers, motion isn't a number.

    But here you are, trying hard to look like you know something about momentum, or energy. However, that knowledge is never "what" they are, only "how" they're related to physicality. Whatever particular philosophy you or anyone might have about physics.

    Physics must have to be the easiest subject to make yourself look like a total dick, when you try explaining what it is
     
  22. exchemist Valued Senior Member

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    Yes, we just know if one calculates these quantities, according to their respective rules (which is what determines what they are), that they are both conserved (in a given frame of reference). This is very useful for solving problems and accounting for behaviour. We do know why they are conserved, though, through Noether's theorem.

    I suppose what I'm giving you is a bit like the "shut up and calculate" response which, famously, is one approach to QM. But really, I think that's all there is to it. Neither is stuff: both are just calculated quantities that are derived properties of a system.
     
  23. arfa brane call me arf Valued Senior Member

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    7,832
    . . . hold up a sec, what "respective rules" of a physical quantity determines what it is? Didn't we both more or less agree that mathematics is silent about what physical things (such as motion) are?
    Usefulness is actually the rule, isn't it? A useless theory is, well, ruled out. As to knowing why energy and momentum are conserved, again, the mathematics in Noether's theory, says nothing about what either of them are. The why is the theory though.

    It would be a mistake to develop a philosophy that says anything that can be calculated or derived, is "not stuff". Now wouldn't it?
     

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