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I disagree with you. Your argument could be made about anything, there is no such thing as a "human" either, it's just a big bunch of wave-particles that does n

I disagree with you. Your argument could be made about anything, there is no such thing as a "human" either, it's just a big bunch of wave-particles that does not have some clear limits. Yet when we talk about a human, we all know what that is, and when a human is seating on a chair we don't think the chair is part of it. The same applies to atoms, we all agree on what they are, and we can show pictures of them etc. The question here is whether spacetime is something like that, or if it is a proxy concept with no grounding whatsoever in the universe, but with good predictive powers? For example, for a long time we believed that Aether filled space, and although we now know this is not the case, the mathematical model provided by the Aether theory was pretty useful. You could very well imagine a world where we know Aether is not real, but continue using it for lack of a better theory as it is a useful framework. > It's even called the atomic _theory_ Theory, in scientific theory, means the opposite of theory in our everyday language though. Theory does not mean a guess, it means a body of work accepted as valid and robustly tested.

AnIdiotOnTheNet 6y ago
> The question here is whether spacetime is something like that, or if it is a proxy concept with no grounding whatsoever in the universe, but with good predictive powers? Consider that "human", "chair", and "atom" are also just concepts are minds apply to certain patters of energy. We all "know what that is" because it is advantageous for our minds to place things in these categories for the purpose of modeling. You may know what a "chair" is, but there are an infinity of gradations between "chair" and any two other objects, like the beanbag chair sitting between "chair" and "pillow". The concept of a chair has no grounding in the universe, it's all in the mind. There are no physics that only apply to chairs. > For example, for a long time we believed that Aether filled space, and although we now know this is not the case, the mathematical model provided by the Aether theory was pretty useful. You could very well imagine a world where we know Aether is not real, but continue using it for lack of a better theory as it is a useful framework. Yes, that's how it works. When we have a better model we use that unless a simpler one will do. Newtonian gravitation isn't "real" by your definition, but we still use it in a lot of circumstances even though we have more accurate models.
- Voloskaya 6y ago
  Right, and that was the point I was trying to make with the human analogy. So the question is whether spacetime is one of those patterns we can point to, like a "human" a "chair" or an "atom", which is what we call "real" in our everyday language, or whether it is only a useful modelization tool, like the Aether. There are no pattern anywhere in the universe matching the Aether. It is a valid question.
  - AnIdiotOnTheNet 6y ago
    I'm saying the differentiation is meaningless. We have a model of space time that makes accurate and measurable predictions and that is as real as real gets.
    - Voloskaya 6y ago
      So then the Aether was real for a while and stopped being real 200 years ago? If we discover a new model that makes better prediction than our current spacetime based model, just like relativity was to Newton's theory, will spacetime stop being real? The article was clearly using "real" with the definition we attach to it in our everyday language, not in deep philosphical sense.
      - AnIdiotOnTheNet 6y ago
        > So then the Aether was real for a while and stopped being real 200 years ago? Yeah, pretty much. > If we discover a new model that makes better prediction than our current spacetime based model, just like relativity was to Newton's theory, will spacetime stop being real? In so far as Newtonian gravitation is also not-real. We still use that model for a lot of things of course. I don't know much about Aether theory or its predictions, so instead I'll use another long gone theory for my example: People used to model the motion of "heavenly bodies" using epicycles, complicated circles-within-circles patterns that assumed the Earth was the center of the universe and everything was taking a very complicated path around it. These epicycles were actually quite good at predicting the motion of planets and stars, so as far as anyone was concerned they were real. Some clever people eventually came around to the idea that all of that could be much more easily and more accurately modeled if we put the sun at the center. Of course we know today that that isn't quite right either. We don't, and possibly cannot, ever know if the models we use to describe the world around us are the most accurate or not. They are real when they work, because we have no better metric to determine their reality.
thisiscorrect 6y ago
"The same applies to atoms, we all agree on what they are, and we can show pictures of them etc." This is where you bury the lede. It's clear if you read many of the comments here that there is no such agreement. Some people _think_ of an atom as something you can reach out and touch, or grok in some deep sense distinct from performing specific experiments. Others take an approach that's more in line with theory in the sense I use it (https://en.wikipedia.org/wiki/Scientific_theory https://en.wikipedia.org/wiki/Scientific_theory). Your definition of theory is too loose: it's not just a body of work. That sounds like a pile of experimental evidence to me. A theory is a robust model or family of related models that match the experimental evidence. Atoms exist in that sense: they're a well tested model of experimental phenomena. I'm certainly not claiming that atomic theory is a wild speculative guess which you seem to imply I've done.
- Voloskaya 6y ago
  > It's clear if you read many of the comments here that there is no such agreement I guess I should have said "all experts agree" instead? Lack of knowledge about something by some people doesn't change the definition of that thing. I would add however, that you can reach out and touch an atom with a certain definition of touch (as touch is mostly a macroscopic concept). > I'm certainly not claiming that atomic theory is a wild speculative guess which you seem to imply I've done. You will have to explain this one to me then. You said "it's *even* called a theory" to reinforce your point that it was just a mathematical tool (and hence not real following your definition). This point is valid only if theory means guess, which it does not.
  - slibhb 6y ago
    Touch isn't any different than measuring radiation interacting with something. These are metaphysical questions, not scientific ones. Scientists, like everyone, have a realist perspective. They consider reality to correspond with appearences. But this is a convention or a metaphysical belief or even a religous belief, it's not scientific.
  - sfifs 6y ago
    > I would add however, that you can reach out and touch an atom with a certain definition of touch (as touch is mostly a macroscopic concept). Don't be so sure... atoms and even relatively large molecules definitely experimentally exhibit [1] wave particle duality in double slit experiments demonstrating they move as waves. Given that absolutely nothing is stationary at any temperature above absolute zero, what are you touching and with what? [1] see end of article https://arstechnica.com/science/2021/01/the-curious-observers-guide-to-quantum-mechanics/ https://arstechnica.com/science/2021/01/the-curious-observer...
JumpCrisscross 6y ago
> The question here is whether spacetime is something like that, or if it is a proxy concept with no grounding whatsoever in the universe, but with good predictive powers? I'd add: is it something one can develop an intuition for? I don't think there is anyone who says gluons or general relativity are intuitive. You have to do the calculations (or memorize heuristics) to get something useful. Atoms, on the other hand, or electromagnetic radiation as another example, can be visualized (and mentally simulated) more or less correctly. (Note: atoms. Not nuclear mechanics.)
- akvadrako 6y ago
  I don't believe anybody can intuitively "visualize" an atom which leads to accurate predictions, especially the electron cloud and it's collapse. Atoms which manage to stay isolated for long enough are not even localized in space.
  - contravariant 6y ago
    Well you can visualize them well enough for basic chemistry if you just view them as spheres with a certain fixed number of lines (bonds) sticking in or out of them. I don't think anyone would call this model real, but it's arguably more relevant to daily life than more fundamental descriptions.

AnIdiotOnTheNet 6y ago

> The question here is whether spacetime is something like that, or if it is a proxy concept with no grounding whatsoever in the universe, but with good predictive powers? Consider that "human", "chair", and "atom" are also just concepts are minds apply to certain patters of energy. We all "know what that is" because it is advantageous for our minds to place things in these categories for the purpose of modeling. You may know what a "chair" is, but there are an infinity of gradations between "chair" and any two other objects, like the beanbag chair sitting between "chair" and "pillow". The concept of a chair has no grounding in the universe, it's all in the mind. There are no physics that only apply to chairs. > For example, for a long time we believed that Aether filled space, and although we now know this is not the case, the mathematical model provided by the Aether theory was pretty useful. You could very well imagine a world where we know Aether is not real, but continue using it for lack of a better theory as it is a useful framework. Yes, that's how it works. When we have a better model we use that unless a simpler one will do. Newtonian gravitation isn't "real" by your definition, but we still use it in a lot of circumstances even though we have more accurate models.

Voloskaya 6y ago
Right, and that was the point I was trying to make with the human analogy. So the question is whether spacetime is one of those patterns we can point to, like a "human" a "chair" or an "atom", which is what we call "real" in our everyday language, or whether it is only a useful modelization tool, like the Aether. There are no pattern anywhere in the universe matching the Aether. It is a valid question.
- AnIdiotOnTheNet 6y ago
  I'm saying the differentiation is meaningless. We have a model of space time that makes accurate and measurable predictions and that is as real as real gets.
  - Voloskaya 6y ago
    So then the Aether was real for a while and stopped being real 200 years ago? If we discover a new model that makes better prediction than our current spacetime based model, just like relativity was to Newton's theory, will spacetime stop being real? The article was clearly using "real" with the definition we attach to it in our everyday language, not in deep philosphical sense.
    - AnIdiotOnTheNet 6y ago
      > So then the Aether was real for a while and stopped being real 200 years ago? Yeah, pretty much. > If we discover a new model that makes better prediction than our current spacetime based model, just like relativity was to Newton's theory, will spacetime stop being real? In so far as Newtonian gravitation is also not-real. We still use that model for a lot of things of course. I don't know much about Aether theory or its predictions, so instead I'll use another long gone theory for my example: People used to model the motion of "heavenly bodies" using epicycles, complicated circles-within-circles patterns that assumed the Earth was the center of the universe and everything was taking a very complicated path around it. These epicycles were actually quite good at predicting the motion of planets and stars, so as far as anyone was concerned they were real. Some clever people eventually came around to the idea that all of that could be much more easily and more accurately modeled if we put the sun at the center. Of course we know today that that isn't quite right either. We don't, and possibly cannot, ever know if the models we use to describe the world around us are the most accurate or not. They are real when they work, because we have no better metric to determine their reality.

thisiscorrect 6y ago

"The same applies to atoms, we all agree on what they are, and we can show pictures of them etc." This is where you bury the lede. It's clear if you read many of the comments here that there is no such agreement. Some people _think_ of an atom as something you can reach out and touch, or grok in some deep sense distinct from performing specific experiments. Others take an approach that's more in line with theory in the sense I use it (https://en.wikipedia.org/wiki/Scientific_theory https://en.wikipedia.org/wiki/Scientific_theory). Your definition of theory is too loose: it's not just a body of work. That sounds like a pile of experimental evidence to me. A theory is a robust model or family of related models that match the experimental evidence. Atoms exist in that sense: they're a well tested model of experimental phenomena. I'm certainly not claiming that atomic theory is a wild speculative guess which you seem to imply I've done.

Voloskaya 6y ago
> It's clear if you read many of the comments here that there is no such agreement I guess I should have said "all experts agree" instead? Lack of knowledge about something by some people doesn't change the definition of that thing. I would add however, that you can reach out and touch an atom with a certain definition of touch (as touch is mostly a macroscopic concept). > I'm certainly not claiming that atomic theory is a wild speculative guess which you seem to imply I've done. You will have to explain this one to me then. You said "it's *even* called a theory" to reinforce your point that it was just a mathematical tool (and hence not real following your definition). This point is valid only if theory means guess, which it does not.
- slibhb 6y ago
  Touch isn't any different than measuring radiation interacting with something. These are metaphysical questions, not scientific ones. Scientists, like everyone, have a realist perspective. They consider reality to correspond with appearences. But this is a convention or a metaphysical belief or even a religous belief, it's not scientific.
- sfifs 6y ago
  > I would add however, that you can reach out and touch an atom with a certain definition of touch (as touch is mostly a macroscopic concept). Don't be so sure... atoms and even relatively large molecules definitely experimentally exhibit [1] wave particle duality in double slit experiments demonstrating they move as waves. Given that absolutely nothing is stationary at any temperature above absolute zero, what are you touching and with what? [1] see end of article https://arstechnica.com/science/2021/01/the-curious-observers-guide-to-quantum-mechanics/ https://arstechnica.com/science/2021/01/the-curious-observer...

JumpCrisscross 6y ago

> The question here is whether spacetime is something like that, or if it is a proxy concept with no grounding whatsoever in the universe, but with good predictive powers? I'd add: is it something one can develop an intuition for? I don't think there is anyone who says gluons or general relativity are intuitive. You have to do the calculations (or memorize heuristics) to get something useful. Atoms, on the other hand, or electromagnetic radiation as another example, can be visualized (and mentally simulated) more or less correctly. (Note: atoms. Not nuclear mechanics.)

akvadrako 6y ago
I don't believe anybody can intuitively "visualize" an atom which leads to accurate predictions, especially the electron cloud and it's collapse. Atoms which manage to stay isolated for long enough are not even localized in space.
- contravariant 6y ago
  Well you can visualize them well enough for basic chemistry if you just view them as spheres with a certain fixed number of lines (bonds) sticking in or out of them. I don't think anyone would call this model real, but it's arguably more relevant to daily life than more fundamental descriptions.