argo Posted February 1, 2019 Author Posted February 1, 2019 Quote On 1/31/2019 at 9:03 AM, studiot said: Could you please give a two line summary of what we are supposed to be discussing? If the issues of fake definitions, the circular nature of the time-flow argument, the focus of the thought experiment or the expansion and energy requirements of the universe are not going to be observed, then nothing else I say is ever going to convince you otherwise. -1
Strange Posted February 1, 2019 Posted February 1, 2019 On 1/30/2019 at 11:33 PM, argo said: I may be wrong and it is quite easy to prove, just provide any hard evidence you have for time-flow This is a straw man argument. The concept that time "flows" is a psychological (or maybe philosophical) one, nothing to do with physics. The definition of time as what clocks measure is in line with other definitions of fundamental properties. Spatial distance is what a ruler measures. Mass is the measured resistance to acceleration. Energy is just a property we measure (and find it is conserved) we can't say what it "is". That is the nature of fundamental properties: they can't be defined in terms of other things. You can say that other things are related to these fundamental properties, like change can be used to measure time or that energy can do work, but this doesn't tell you any more about what these things are. (The fact that change is a measure of time might be what gives rise to the illusion of time "flowing").
swansont Posted February 1, 2019 Posted February 1, 2019 6 hours ago, argo said: If the issues of fake definitions, Fake definitions has been claimed without evidence Quote the circular nature of the time-flow argument, Not unique to time. All definitions are ultimately circular, unless you have some sort of axiom, postulate or artifact that you can refer to. e.g. my example of length. Define that in a non-circular way.
studiot Posted February 1, 2019 Posted February 1, 2019 6 hours ago, argo said: Quote On 1/30/2019 at 11:03 PM, studiot said: Could you please give a two line summary of what we are supposed to be discussing? If the issues of fake definitions, the circular nature of the time-flow argument, the focus of the thought experiment or the expansion and energy requirements of the universe are not going to be observed, then nothing else I say is ever going to convince you otherwise. I am even more confused than ever by this response. It is certainly not an answer to the question I asked, which therefore still stands. Note that others have also found it difficult to spot the kernel of your point, indeed their points of response to yours have already been split off elsewhere.
Eise Posted February 1, 2019 Posted February 1, 2019 (edited) On 1/30/2019 at 11:33 PM, argo said: The contradictory nature of the definition of time in the real world always leads to circular arguments which are vaguely acknowledged but then deceptively downplayed and finally ignored In formal and (in their domain) complete theories, one always will have circular definitions. Examples: F = ma. Try to define mass without referring to a force, or the other way round. (OK, you could do it by referring to Lagrangian, energy, etc but if you look carefully you will see that you always took something on board implicitly you did not define yet, and then, if you do, you will have to refer to a concept you already were using). Evolution: the survival of the fittest. Who is the fittest? The one that survives... It is simply the case that definitions of concepts are always circular. It cannot be different. One could even go one step further: every definition is a tautology. And with time it is not different. But what makes a theory scientific (math excluded...) is that one can make operational definitions. That means, one can define concepts as actions to take and observations to make. In this way one establishes that a theory is about something. In short: conceptual definitions are always circular; operational definitions are not. The idea of time-flow is more or less just a metaphor. Things flow in time*, or better, processes occur in time. Time itself does not flow. Normally what one means is that the time we call 'present' is ever going onwards. But this is just an example of an indexical. Indexicals are words which meaning is completely context dependent. Examples are 'I' (meaning the speaker), 'here' (the place where the speaker is), and, yes, 'now' (the moment that a speaker utters a sentence). For these do not exist any hard physical references. So the 'flow of time' is not a physical concept. But you treat it as such. Many laws of physics have a dependency on time: this means that we can describe how things change in time. But for laws of physics to become really empirical we need an operational definition of time. Practically, we do this be using 'standard changers', aka clocks: some regular process, where we can count the number of regular changes (tick-tack-tick...). And as a final remark: you know that physics just works. One can predict solar eclipses many years in advance on the second, special relativity is tested to the bone and is more or less the touchstone for every fundamental law of physics (they must be Lorentz-invariant), general relativity has until now withstood every empirical test: so there cannot be much wrong with the physical understanding of time. * On second thought, no, things do not flow in time. They flow in space... 'Flowing in time' is still metaphoric speech. Edited February 1, 2019 by Eise Added footnote after rereading. 1
dimreepr Posted February 1, 2019 Posted February 1, 2019 (edited) 21 hours ago, swansont said: Not sure how that comes out of what I said. It put me on a train of thought that terminated with a question that should have started with is. or a new topic Edited February 1, 2019 by dimreepr
Ten oz Posted February 1, 2019 Posted February 1, 2019 7 hours ago, argo said: If the issues of fake definitions, the circular nature of the time-flow argument, the focus of the thought experiment or the expansion and energy requirements of the universe are not going to be observed, then nothing else I say is ever going to convince you otherwise. Time is observed as a measurement. Reading a clock requires observation which requires an observer. Humans are that observer and humans experience things comparatively. To us time flows in a prescribed manner. While time may not be linear in absolute terms we (humans), per our state of existence, experience it linearly. Many measurements are abstract like this. How would you define big, fast, soft, loud, hot, heavy, wet, tall, and etc in absolute terms free from comparative observation?
studiot Posted February 1, 2019 Posted February 1, 2019 (edited) 34 minutes ago, Eise said: In formal and (in their domain) complete theories, one always will have circular definitions. Examples: F = ma. Try to define mass without referring to a force, or the other way round. (OK, you could do it by referring to Lagrangian, energy, etc but if you look carefully you will see that you always took something on board implicitly you did not define yet, and then, if you do, you will have to refer to a concept you already were using). [aside] You really find Newton's Laws circular? In modern terms N1 Defines motion and its relation to coordinate systems of space and time and introduces, but does not define an antity called Force. N2 Defines a force in terms of those cooordinate sytems and introduces a constant of proposrtionality called Mass. N3 Defines Mass. [/aside] I was careful in my response to the OP to avoid circularity. I am still waiting for his reply to tell us the exact point he wishes to discuss out of a long and rambling opening post. Edited February 1, 2019 by studiot
swansont Posted February 1, 2019 Posted February 1, 2019 22 minutes ago, studiot said: N3 Defines Mass. It does?
Strange Posted February 1, 2019 Posted February 1, 2019 1 hour ago, studiot said: N2 Defines a force in terms of those cooordinate sytems and introduces a constant of proposrtionality called Mass. N3 Defines Mass. The second law defines force in terms of (undefined) mass. Or mass in terms of (undefined) force. (as long as we assume, in both cases, that acceleration has previously been defined.) As force is a fairly intuitive concept ("how hard you push") it may be easiest to consider this as defining inertial mass (resistance to being moved). The third law doesn't define anything new, as far as I can see.
Eise Posted February 1, 2019 Posted February 1, 2019 For the record: Newton defined mass as "the amount of matter which is determined by its volume and density". Isn't that great? Try to define 'density' without referring to mass... 2
studiot Posted February 1, 2019 Posted February 1, 2019 1 hour ago, Eise said: For the record: Newton defined mass as "the amount of matter which is determined by its volume and density". Isn't that great? Try to define 'density' without referring to mass... For which record? Newton well understood the difference between inertial mass and gravitational mass. Was the above definition a definition or an interpretation? Back to the question I asked you 3 hours ago, studiot said: You really find Newton's Laws circular? In modern terms N1 Defines motion and its relation to coordinate systems of space and time and introduces, but does not define an antity called Force. N2 Defines a force in terms of those cooordinate sytems and introduces a constant of proposrtionality called Mass. N3 Defines Mass. Note I said "in modern terms" So I was clearly not thinking of Newton't interpretation. Furthermore he did not write an equation. Equations were not invented until after his death. He wrote (as I put above) 'proportional to' as was the custom of his time to work in terms of proportionality. However I think detailed discussion, if desired, belongs in another thread, not one about timeflow. Apologies for the poor spelling earlier.
Mordred Posted February 1, 2019 Posted February 1, 2019 (edited) 6 hours ago, Eise said: Try to define 'density' without referring to mass... Hrrm interesting challenge, Lets see the average value of a function (example probability density) or quantity in a given volume. Mass being resistance to inertia change (modern definition ) defined by f=ma would quality under the first portion. Edited February 1, 2019 by Mordred
Eise Posted February 2, 2019 Posted February 2, 2019 19 hours ago, studiot said: Newton well understood the difference between inertial mass and gravitational mass. Was the above definition a definition or an interpretation? AFAIK this was Newton's definition. I think it shows he was aware that there was something circular in his F = ma. He put the problem under the carpet... 23 hours ago, studiot said: N3 Defines Mass. I have no idea why Newton's 3rd law would define mass. 14 hours ago, Mordred said: Hrrm interesting challenge, Lets see the average value of a function (example probability density) or quantity in a given volume. Mass being resistance to inertia change (modern definition ) defined by f=ma would quality under the first portion. But then you turn back to f = ma. Did you really avoid circularity? 19 hours ago, studiot said: However I think detailed discussion, if desired, belongs in another thread, not one about timeflow. You are right. It was just an example of a very valid theory, which in its core has circular definitions of its basic concepts. It serves as an example that circularity of definitions is not a valid critique on scientific theories. It would be, if the concepts are underdetermined, i.e. we have not enough operational definitions to 'span the theory space'. A complete scientific theory should be able to predict every event in its domain, given the starting conditions, and the minimum of operational definitions 'to fill the theory with real values'. So argo's critique on the circularity is just beating hot air.
Outrider Posted February 2, 2019 Posted February 2, 2019 On 1/30/2019 at 5:03 PM, studiot said: Could you please give a two line summary of what we are supposed to be discussing? Alright I couldn't get it down to two lines. But I think this is Argo's hypothesis. On 1/30/2019 at 4:33 PM, argo said: THOUGHT EXPERIMENT The photo in the frame is a thought experiment that’s goes some way to proving time-flow is impossible by showing the mechanics involved. Assuming the whole universe was a photograph and time is an overlaying frame then there are only two options for making the pixels in the photo move. The first option is the contemporary view that time is a fourth dimension overlaying the three spatial dimensions all at once, if the original photo was to move to the next frame all the pixels would still be in the same place i.e. there would be no movement at all so this is not an option at all. A completely new photo must therefore be taken with the pixels in their new positions each and every time, this all apparently happens as time flows from frame to frame in some inexplicable way. The second option is that time is a fourth dimension that overlays the three spatial dimensions but does so individually with a different frame for every part, every part/pixel in the universe/photo now has its own unique tiny time frame around it and is free to move independently meaning both linear and non-linear motions are accounted for. The mechanics involved are each new time surrounds a quantity of space, making particles of space and time, movement is just movement of these particles nothing more and time is defined as the when and where something exists nothing more, especially not the facilitator of movement in the universe. * That's as short as I could as I could make it. So my questions are directed not only towards Argo but all the thread participants. 1. Would it be better to say space-time overlays the other 3 spatial dimensions? 2. Assuming Argo's hypothesis is correct would it really change anything? Argo Could you please provide a peer reviewed paper claiming that "time flows" or drop your claim that the scientific community maintains that it does? Or better yet focus on supporting your idea! 1
koti Posted February 2, 2019 Posted February 2, 2019 Perhaps it would be easier for the OP to accept the definition of time in physics if he understands that both time and distance are relative depending on the observers reference frame. Intuitively you wouldn’t want to look for tangible properties of a meter or a mile, the same goes for time but I guess its a little less intuitive.
Strange Posted February 2, 2019 Posted February 2, 2019 58 minutes ago, Outrider said: Alright I couldn't get it down to two lines. But I think this is Argo's hypothesis. I have no idea if that accurately reflects Argo's thoughts, but kudos for trying! 58 minutes ago, Outrider said: 1. Would it be better to say space-time overlays the other 3 spatial dimensions? I don't like/understand the term "overlay". We are simply going from a model based on three dimensions of space to one based on four dimensions. Time doesn't "overlay" the others, it is just added to them. If you have a 2D square that you then project to form a 3D cube, you wouldn't say that the 3rd dimension "overlays" the others. Would you. The idea of a series of photographic stills (like the frames of a movie) stacked up one behind the other, is a reasonable analogy for the concept of spacetime. Apart from the facts that: - It only works for 2D space, but that's OK for an analogy. - Time is continuous, so there aren't a series of frames, there is a continuous change - It doesn't capture the fact that observers in different frames of references (eg. relative motion or gravitational potential) will see these frame differently. If you think of a cube where 2 dimensions are space and the third dimension, time, is slices space into individual frames, then you have to imagine that different observers slice things up at a different angle. (Really need a picture for that, I guess.) Quote if the original photo was to move to the next frame all the pixels would still be in the same place I don't understand that objection. If nothing was moving, then that would true. But anything moving would appear at a different location in each frame.
Outrider Posted February 2, 2019 Posted February 2, 2019 Thanks for the answers Strange. I gain new insights in the strangest of threads. 10 minutes ago, Strange said: Time is continuous, so there aren't a series of frames, there is a continuous change But isn't this still up in the air? I suspect that time isn't quantitized but I was under the impression that the scientific consensus at the moment is we just don't know. BTW the third quote in your response isn't mine. I don't have the prerequisites to be making assertions on this subject.
Mordred Posted February 2, 2019 Posted February 2, 2019 (edited) 2 hours ago, Eise said: But then you turn back to f = ma. Did you really avoid circularity? I don't believe so as, the f=ma was in reference to mass, however the definition I gave for density does not require mass. If you note a probability density function does not require mass. It could be the probability density to locate a particle or the probability density of the number of sheep in a field as two examples. The f=ma was simply an example of an applicable density function. The mathematical formulas of Newton's laws of inertia change is how mass is mathematically defined under physics. Anytime a mass term is used those laws apply. The directly relates to the verbal definition of resistance to inertia change. The term mass is defined via the formula itself. Edited February 2, 2019 by Mordred
Strange Posted February 2, 2019 Posted February 2, 2019 14 minutes ago, Outrider said: But isn't this still up in the air? I suspect that time isn't quantitized but I was under the impression that the scientific consensus at the moment is we just don't know. That is probably more accurate. GR requires it to be continuous. It is thought that in a quantum theory of gravity it would be quantised. But attempts to test if spacetime is spacetime have produced negative results. 17 minutes ago, Outrider said: BTW the third quote in your response isn't mine. I don't have the prerequisites to be making assertions on this subject. Yeah, sorry. The forum isn't good with nested quotes. I'll see if I can fix it.
studiot Posted February 2, 2019 Posted February 2, 2019 1 hour ago, Outrider said: Argo The first option is the contemporary view that time is a fourth dimension overlaying the three spatial dimensions all at once, ……………... The second option is that time is a fourth dimension that overlays the three spatial dimensions ……………………………... Thank you for attempting that clarity, you have perhaps identified and picked out the major fallacy in the OP. +1 By definition one dimension does not overlay another ever. Dimensions are representations of independent variables. The rest of the OP is just an unsuccessful attempt to break this independence. Pixels references, for instance, are a red herring. 1
Mordred Posted February 2, 2019 Posted February 2, 2019 (edited) 9 minutes ago, studiot said: By definition one dimension does not overlay another ever. Dimensions are representations of independent variables. a side note we can however overlay different fields, which are assigned values/functions under a geometric basis. The different fields typically but not always have the same dimensional axis. ie 3 spatial and 1 time for example. lets use an example under the same coordinate basis, {ct, x, y, z} I can overlap the Minkowskii field [latex] \eta_{\mu\nu}[/latex] with the permutation field [latex] g_{\mu\nu}[/latex] this results in a resultant field [latex] g_{\mu\nu}[/latex]. Note a the first two tensors describe two distinct types of fields. The Minkowskii can be described as a scalar field while the latter can be either a scalar or vector field. Edited February 2, 2019 by Mordred
studiot Posted February 2, 2019 Posted February 2, 2019 6 minutes ago, Mordred said: a side note we can however overlay different fields, which are assigned values/functions under a geometric basis. Sometimes. But not always. As a for instance we can plot atomic weight against atomic number. This example has the advantage of not including any of the spacetime variables. We cannot overlay them.
Mordred Posted February 2, 2019 Posted February 2, 2019 (edited) True not in all applications we cross posted I had added an example of one case where we can and do under GR. (in this case I used the weak Newton limit GR solution) [latex] g_{\mu\nu}=\eta_{\mu\nu}+h_{\mu\nu}[/latex] the advantage here and one of the reasons its possible to overlap in this case is that all three fields share the same coordinate axis (identical dimensional basis) Edited February 2, 2019 by Mordred
studiot Posted February 2, 2019 Posted February 2, 2019 Further, those tensors are not independent variables. They are dependent upon the basis variables for the space, in some regular and definable manner, unlike my example.
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