Are space and time definable without atoms?

[ZapperZ]

Surely the obvious answer is that the question was speculative and discussion would not have been tolerated in other parts of the forum?

On your general point of who is qualified to philosophise, I do in general agree. But I would prefer it if you distinguished between philosophy/science how it should be done, and philosophy/science as it is mostly done.

That's true, and my intention in the beginning was to ask why it was asked in this specific forum, rather than asked in the field of philosophy in general. However, I think the latter is also valid and the issue may have evolved into that. Still, I have not met any philosopher who has told me that philosophy can solve physics issues, or even provide definitions to physics concepts. What they do say is that philosophy can provide "insights" into various aspects of physics principles that may be beyond what physics is willing to say. But doing this doesn't solve or provide an answer to what the OP wants.

As for your first point, note that the PF Guidelines apply to ALL forums here on PF. So posting this outside the physics sub-forums does not absolve it from the same requirement when discussing physics issues.

Zz.

 

[Pythagorean]

A philosopher cannot try to extrapolate what QM is trying to say if all he/she understood about QM is reading some pop-science books! Call me silly, but I don't see any other way of being able to do this other than to start with the same level of understanding as other physicists in terms of the physics.
Zz.

Well, I actually come in here as someone who was trained formally in QM and brush up on it by answering philosophical questions about it. I find myself correcting misleading philosophical notions, but I don't think it's destructive for them to have "asked" (or wrongly stated) in the first place and it's good for me to think about QM in ways outside of "solve this problem".

Otherwise the misleading notions just stay quietly in the philosopher's head, possibly as the premise for other notions. It's not until he vocalize (or posts, in this case) his misnomer's that they can be corrected.

 

[ZapperZ]

Well, I actually come in here as someone who was trained formally in QM and brush up on it by answering philosophical questions about it. I find myself correcting misleading philosophical notions, but I don't think it's destructive for them to have "asked" (or wrongly stated) in the first place and it's good for me to think about QM in ways outside of "solve this problem".

Otherwise the misleading notions just stay quietly in the philosopher's head, possibly as the premise for other notions. It's not until he vocalize (or posts, in this case) his misnomer's that they can be corrected.

Asking philosophical questions on QM in here is exactly the right place to ask.

Asking QM questions to a physicist or in the physics forums is exactly the right place to ask.

Asking QM questions to philosophers or in the philosophy forum is what is puzzling to me.

Do you now see what I'm getting at? The OP is a physics question. I haven't seen anyone who has provided a convincing argument that it isn't.

Zz.

 

[ConradDJ]

Asking QM questions to philosophers or in the philosophy forum is what is puzzling to me.

Do you now see what I'm getting at? The OP is a physics question.

I agree with you, that was a physics question, and I appreciate the guidance on the forums. I'll see if I can make it clear that the point is not to demolish SR & GR! -- and post it elsewhere.

Conrad

 

[Pythagorean]

ZapperZ,

I understand your sentiments in general, and I agree that a lot of answers in Conrad's post could have been answered more productively in the physics forum, but he also had an obvious philosophical tone to his post.

Here are some examples (bolding added):

I’m not clear exactly how to define the “functionality” of atoms, because it’s complex and multifaceted. But it does seem that the emergence of atoms represents a very large step in the evolution of our universe, considered as a system for defining and communicating information. Before there were atoms, I’m wondering whether space and time would have been meaningfully definable?

Of course we can just posit a spacetime continuum (or whatever) as a mathematical structure, along with mathematical laws of dynamics, etc. But maybe our ability to define something logically is less significant than the ability of the physical world to define itself concretely, in actual measurements.

I'm not saying it shouldn't have been posted in physics forums. I'm disagreeing with the statement that it shouldn't have been posted in philosophy forums. It works in both.

Given the general attitude of the moderators around here though, I'd be more likely to post something in philosophy forums if it seemed to border on both. It's harder to break the rules here and there's a lesser chance of infraction.

 

[disregardthat]

Exactly what they were before! You assertion is just crazy.

They are exactly what we call them. Every notion and term is bound to the human consciousness which defines and perceives them.

 

[DaveC426913]

They are exactly what we call them. Every notion and term is bound to the human consciousness which defines and perceives them.

I think you've lost track of the discussion.

This isn't about what they're named, it's about whether space and time existed before man conceived of them. My point is that space and time existed long before we conceived of it, as witnessed by the fact that dinosaurs and rocks made use of them before our conceiving of - let alone naming anything.

 

[disregardthat]

I think you've lost track of the discussion.

I consider our talk a side-discussion.

This isn't about what they're named, it's about whether space and time existed before man conceived of them. My point is that space and time existed long before we conceived of it, as witnessed by the fact that dinosaurs and rocks made use of them before our conceiving of - let alone naming anything.

When you are talking about them, you are talking about what you have already defined. Time and space are, as well as objects, entities defined by human beings. Who are you to talk about some objective world independent of your perception? Dinosaurs and rocks existed before human beings in our perception of the world, in the world where we use our own defined terms based on our own perception.

To put it straight: Dinosaurs existed before us in our perception of the world, but saying that dinosaurs exist independently of human beings is meaningless because dinosaurs is a term defined by human beings.

 

[Evo]

I consider our talk a side-discussion.

When you are talking about them, you are talking about what you have already defined. Time and space are, as well as objects, entities defined by human beings. Who are you to talk about some objective world independent of your perception? Dinosaurs and rocks existed before human beings in our perception of the world, in the world where we use our own defined terms based on our own perception.

To put it straight: Dinosaurs existed before us in our perception of the world, but saying that dinosaurs exist independently of human beings is meaningless because dinosaurs is a term defined by human beings.

It doesn't matter what we choose to call them. We know what they are and we know they existed. Your argument makes no sense. A name has nothing to do with something that existed before us. A name has nothing to do with something that exists now.

 

[disregardthat]

The point is that 'them' is referring to 'our perception of them'. We define them as objects (or subjects), we give them properties based on our perception of them. 'They' would make no sense without the human mind to recognise them as such. They have existed before us 'in our perception of the world'.

Let's keep it within our frame of perception. We have nothing to say outside of it because we are by definition bound within it.

 

[DaveC426913]

The point is that 'them' is referring to 'our perception of them'. We define them as objects (or subjects), we give them properties based on our perception of them. 'They' would make no sense without the human mind to recognise them as such. They have existed before us 'in our perception of the world'.

Let's keep it within our frame of perception. We have nothing to say outside of it because we are by definition bound within it.

No.

You will discover this to be an ultimately pointless exercise. But I suppose everyone has to go through it at some point in their lives...


Descartes had this same dilemma - that our senses are suspect, and how can we ever "know" anything. His resolution was to realize that it is pointless to question whether our perceptions are "real". It doesn't matter if they are or if they are not, they are all we have.

The modern equivalent is to ask if we are in a giant computer simulation, being fed every bit of data (yes, a la Matrix). We can always ask this question, but to what end? The answer is always the same. We proceed as if what we see is the most real thing we have access to. In principle, what we do is, before every human discourse utter the mantra "Everything we sense is only through our sense and can be suspect. That being said, I will now proceed with my statements as certainty, with the aforementioned caveat."


This goes for every word uttered by any human anywhere. Thus it drops out of the question - an unspoken premise. We are left to discuss our universe as if it is real in every way.

If you want to be paralyzed by the doubt that what you sense is suspect, more power to you, but the rest of us don't have to.

So:

Inasmuch as our senses tell us anything, dinosaurs lived and died before Man came on the scene. Full stop. Dinosaurs made use of space and time before Man named them. Full stop.

'them' is referring to 'our perception of them'.

This literally goes without saying. It therefore has no impact on the discussion.

 

[DaveC426913]

I consider our talk a side-discussion.

Yes. Which is tantamount to an attempt to derail the thread. Let's stay on track.

 

[ConradDJ]

I think you've lost track of the discussion.

This isn't about what they're named, it's about whether space and time existed before man conceived of them. My point is that space and time existed long before we conceived of it, as witnessed by the fact that dinosaurs and rocks made use of them before our conceiving of - let alone naming anything.

The question I was trying to raise originally is not about how humans define space and time, but how the physical world does it. Probably using "define" in this unusual way was not conducive to clarity.

I suspect that it may be a remarkable fact, relevant to foundational physics, that space and time not only "exist" (in whatever sense) but can be physically measured (and "defined" in that sense).

As I suggested in another post, it's easy to make up mathematical models of the universe in which space and time are not measurable at all.

https://www.physicsforums.com/showthread.php?p=2138202#post2138202

In fact, I'm not sure whether any of our models explicitly give a basis for space-time measurement. Certainly General Relativity does not, and that's something that caused Einstein some concern. We can define space and time in GR mathematically, but to give the mathematics meaning in terms of observables we have to have actual measuring-rods and clocks of some kind. Which can't be done, I suspect, without atoms.

No doubt space and time "existed" before there were humans, and maybe it even makes sense to think about how space-time was structured before there were atoms to measure it. That I'm less sure about. Quantum theory suggests that where something is not measurable, we shouldn't assume it "exists" in a specific determinate state.

 

[ZapperZ]

If you were to ask this in, say, the physics forums, here's how I would have tackled this based on what we know now:

When we say that something is defined based on something (the way you are trying to imply with your topic question), then we should be able to test it out. For example, superconductivity is defined based on the existence of the supercurrent, which is the charge carrier that flows without any resistance. So superconductivity depends on the supercurrent.

How do we test that? I can, for example, change the supercurrent density and see what happens as I do the same set of tests, such as measuring the critical supercurrent density, the critical magnetic field, etc... Now, IF, by changing the supercurrent density that I don't see ANY change in the superconductivity properties that I'm measuring, then I will have to question that original premise that superconductivity is defined by the supercurrent. If A is defined by B, then changing B should affect A. If it doesn't, then I will have to re-examine my original premise.

Now, get back to your question. "Are space and time definable without atoms?"

Assume the premise that "Space and time are define with atoms". I will interpret this literally.

(1) does this mean that an electron sees no space since it is not an "atom"?

(2) What if I start pumping on a vacuum chamber and reduce the amount of atoms in that volume? If time and space are define by atoms, then the presence of LESS atoms should affect both of them. Where is the effect? I work with ultra-high vacuum system (better than 10^-9 Torr). Did I just destroyed a lot of space and time in my vacuum chamber? How come the electrons that I measured moving in that chamber didn't detect such destruction?

These are not "philosophical" issues because these are physical issues that one CAN test based on a starting premise. Rather than argue about something based on a matter of TASTES (a discussion that normally solves nothing and goes nowhere), wouldn't it be more productive to actually set out a series of tests to evaluate the VALIDITY of such a statement?

After all, you DO want SOME answer and resolution to what you're asking about, don't you?

Zz.

 

[DaveC426913]

(2) What if I start pumping on a vacuum chamber and reduce the amount of atoms in that volume? If time and space are define by atoms, then the presence of LESS atoms should affect both of them. Where is the effect?

I think the response would be 'how can we tell if there's time in that vacuum without the introduction of a clock?'

But you're right. We could do all sorts of the measurements on the vacuum without atoms. Pass a beam of light through it, or a beam of electrons. We can measure their phase and other properties once they emerge. We will know what has happened to them in the interim.

 

[ZapperZ]

I think the response would be 'how can we tell if there's time in that vacuum without the introduction of a clock?'

Send one of those Cs atoms use in atomic clocks through a vacuum and see if the frequency goes out of phase.

Zz.

 

[disregardthat]

You will discover this to be an ultimately pointless exercise. But I suppose everyone has to go through it at some point in their lives...

That belittling tone degrades your argument. Don't discard arguments because your opinion does not agree with it.

The modern equivalent is to ask if we are in a giant computer simulation, being fed every bit of data (yes, a la Matrix). We can always ask this question, but to what end? The answer is always the same. We proceed as if what we see is the most real thing we have access to. In principle, what we do is, before every human discourse utter the mantra "Everything we sense is only through our sense and can be suspect. That being said, I will now proceed with my statements as certainty, with the aforementioned caveat."

That is not at all my point. I am not paralysing our way of gaining knowledge, I am not questioning the scientific way. The problem arises when one tries to say something independently of human experience. We are humans. Our knowledge arises from our own experience of the world we live in. By our perception we define the concepts which we apply to our world. Dinosaurs, as everything else, are perceived and defined by human beings. Talking about something independently from our own perspective is meaningless.

This goes for every word uttered by any human anywhere. Thus it drops out of the question - an unspoken premise. We are left to discuss our universe as if it is real in every way.

Yes, indeed it is an unspoken premise. As long as we confine ourself to our own perspective. When one talks about something independent from human experience in the physical world we go beyond our premises.

If you want to be paralyzed by the doubt that what you sense is suspect, more power to you, but the rest of us don't have to.

I am not doubting our knowledge of the world gained through the scientific method, that would be pointless. However, believing that our perception fundamentally defines an objective world independent from our experience is pointless.

 

[disregardthat]

Yes. Which is tantamount to an attempt to derail the thread. Let's stay on track.

I am not trying to derail the thread. I am trying to continue our discussion.

 

[Evo]

That is not at all my point. I am not paralysing our way of gaining knowledge, I am not questioning the scientific way. The problem arises when one tries to say something independently of human experience. We are humans. Our knowledge arises from our own experience of the world we live in. By our perception we define the concepts which we apply to our world. Dinosaurs, as everything else, are perceived and defined by human beings. Talking about something independently from our own perspective is meaningless.

We have to base our knowledge on what we perceive and that includes the scientific method, what we perceive from scientific results are just our interpretation of data. You are making no sense. Please stop, you are derailing the thread.

 

[DaveC426913]

That belittling tone degrades your argument. Don't discard arguments because your opinion does not agree with it.

It is not meant to be belittling. Apologies.

Pointless doesn't mean 'dumb' in this case, it means once you follow this logic to its end, you will arrive at the same conclusions that almost every other thoughtful person has at one point or another. i.e. the concept that we can only perceive through our senses ultimately has absolutely no effect on how we proceed. Again, just pretend every sentence starts with 'While I acknowledge that our senses may be flawed, I observe thus...'

I'm going to draw the line here. If you wish to continue along this line, you'll have to start a new thread to discuss it. (Though before you do so, you might want to brush up on all the other threads about this exact topic.)


Again, whether or not we are here to perceive them, the human body of knowledge (flawed and limited as it may be) concludes that indeed, dinosaurs lived, roamed and died in both space and time. Nothing you've said changes that.

 

[disregardthat]

Again, just pretend every sentence starts with 'While I acknowledge that our senses may be flawed, I observe thus...'

Of course I agree with you on that. Anything else would be hopelessly pessimistic and pointless. That is, however, not the issue. The problem arises when you are starting to talk about something independent from the human mind in which all interpretation of experience originates. (Dinosaurs are also subjects of our experience) I do believe that you don't understand exactly what I mean based on my interpretation of your reply, but I will not discuss this further as it is obviously not wanted here.

 

[DaveC426913]

but I will not discuss this further as it is obviously not wanted here.

Feel free to discuss, just start a new thread. It's not that no one wants to pursue it, it's that you're derailing the thread.

 

[ConradDJ]

If you were to ask this in, say, the physics forums, here's how I would have tackled this based on what we know now:
...
These are not "philosophical" issues because these are physical issues that one CAN test based on a starting premise. Rather than argue about something based on a matter of TASTES (a discussion that normally solves nothing and goes nowhere), wouldn't it be more productive to actually set out a series of tests to evaluate the VALIDITY of such a statement?

Zz -- thanks for the very relevant response... despite my starting this thread in the wrong forum! You suggest that -- treating this as a physics question -- we should be able to do an experiment that gives us an answer.

The thing is, any conceivable experiment we perform -- tracking the motion of an electron in a vacuum, for example -- will involve making space and time measurements using atomic matter. If that's so, it's maybe impossible to test whether the spacetime structure we observe depends on the existence of atomic matter. That would makes it a useless question from the standpoint of normal, everyday physics.

The reason I think the question might not be useless is this. Our current theories tell us that atoms first came into being something like 300,000 years after the universe began. Those theories also explain a lot about the universe, on the assumption that the structure of space and time and the laws of physics were well-defined and essentially the same as they are today, going back all the way to the first microseconds. So there is a lot of evidence that says, spacetime structure has nothing to do with atoms!

Yet, Quantum Mechanics gives us a general prescription that at the fundamental level, if something isn't measured, it should be described as a superposition of all its possible states. So it might make sense to imagine that before there were atoms, space and time (and physical laws) should be described as a superposition of all possible configurations, and that the emergence of atoms amounted to a cosmic "measurement event" in which one configuration was selected that was capable of defining / measuring itself.

Since we ourselves exist within that configuration, and gather all our data using atomic matter (and the laws of physics that support it), perhaps it makes sense that we can now construct a consistent history of our universe going back long before there were atoms... as if those same principles were always valid.

But in QM, you can verify the existence of superpositions by showing interference between alternate possibilities. If there's no possibility of doing that with respect to different pre-atomic configurations of our universe, this again may not be a testable hypothesis.

Even so, it might turn out to be a way of explaining why the complicated structure of the laws of physics is the way it is. It seems to open up the possibility of a functional analysis, where we could say -- we have to have several different fundamental stuctures, like the electromagnetic field and the gravitational field, because we can only measure and define anyone of them in terms of the others. The laws of physics need to be "finely-tuned" to support the existence of stable, steadily oscillating structures like atoms, because those structures are needed to measure space and time, etc.

Physics already gives us specific dependencies between matter and gravitation, electric charge and the e/m field, etc. But we don't have an explanatory approach that can meaningfully ask, why we have these very different kinds of structure, and why they work so well together to support all the diverse phenomena in our universe. So asking about what it takes to measure (physically define) space and time is groping toward an approach that might eventually make those questions meaningful for physics.

 

[ZapperZ]

Zz -- thanks for the very relevant response... despite my starting this thread in the wrong forum! You suggest that -- treating this as a physics question -- we should be able to do an experiment that gives us an answer.

The thing is, any conceivable experiment we perform -- tracking the motion of an electron in a vacuum, for example -- will involve making space and time measurements using atomic matter. If that's so, it's maybe impossible to test whether the spacetime structure we observe depends on the existence of atomic matter. That would makes it a useless question from the standpoint of normal, everyday physics.

But that's the whole point! We KNOW how things would be have in "ordinary" spacetime. If that spacetime goes weird for some kind, we SHOULD be able to detect some strange outcome. We already have seen what happened when spacetime gets warped via gravitational lensing.

There have been several attempts at figuring out if the speed of light will be different if space truly is not continuous and we bump into the Planck limit. This is how one would TEST such a thing, not simply via handwaving argument. The whole issue of making precise measurement of the speed of light under very precise condition and trying to detect any violation of Lorentz invariance is preciously the SAME issue that you have stated. So YES, there are theories and circumstances that we should be able to detect such an effect, even when we use "atoms" to detect light. You are forgetting that light also has a phase, and such phase difference is what we tend to use when its normal path doesn't quite match.

But the other part of this argument is, if you truly, TRULY think that any kind of variation cannot be inherently detected, then what's the big issue? If one can't distinguish one from the other, than the conventional idea prevails, because your idea cannot produce one single verifiable difference from something that we KNOW already works. Then all of your effort here has been a waste of time. When you go to someone, especially a physicist, and tell him/her that you have this tremendous idea, really revolutionary, but that everything that it predicts matches already what the already-established idea predicts, what you get will be a big yawn and a rapid loss of interest.

And I'm afraid, that is what I'm approaching now...

Zz.