Uncertainty… principle?
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28-04-2014, 12:51 PM
RE: Uncertainty… principle?
(28-04-2014 04:24 AM)living thing Wrote:  When I take a photograph of a scene around me, the universe keeps going but the things in the picture stop moving.
If you are literally talking about a photograph then that is a representation of the light that went into your lens in a brief moment of time.

If you are talking about a freeze in time then you must consider conservation of energy. To stop a moving object you need to apply a force, you need to convert energy, the energy cannot simply disappear.

(28-04-2014 04:24 AM)living thing Wrote:  In order for me to accept that the object has an instantaneous velocity even though I can’t see it, I must accept the premise that momentum and kinetic energy still occur during the zero length of an instant, but that is the conclusion that you are trying to draw.
It is backed up by centuries of empirical scientific evidence. If you think momentum and kinetic energy have all of a sudden gone then you need to account for that. Where did the energy go?

(28-04-2014 04:24 AM)living thing Wrote:  I don’t think energy can be created or destroyed; there was never less than there is now, and there will never be more than there is now. Which leads to an interesting question: what happened 13.8 billion years ago?
Whose to say that the energy within our universe wasn't present prior to the big bang event? Whose to say that energy isn't an intrinsic property of nothing?
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28-04-2014, 01:53 PM
RE: Uncertainty… principle?
(28-04-2014 12:51 PM)Stevil Wrote:  If you are literally talking about a photograph then that is a representation of the light that went into your lens in a brief moment of time.

If you are talking about a freeze in time then you must consider conservation of energy. To stop a moving object you need to apply a force, you need to convert energy, the energy cannot simply disappear.
Of course the energy cannot simply disappear, that is why I cannot freeze time. If I wanted to actually freeze the real universe in one specific instant, I would have to not only subtract all kinetic energy from every structure in relation to every other, but also subtract their potential energies in order to prevent them from accelerating towards or away from other structures; and that is extremely tricky if not impossible. If I knew how to do that, I wouldn’t need to catch a plane ever again.

But in order to imagine a universe frozen in time, I can simply imagine what it would be like if nothing moved in relation to anything else.

Conservation of energy implies that I cannot stop time from progressing, but it does not mean that kinetic energy is still there during a zero length instant. In fact, the way things don’t move when I capture only a brief moment of time does suggest that motion does not occur during a zero length instant. It is only when I capture larger intervals of time when the location of things in the picture becomes diffuse.

(28-04-2014 12:51 PM)Stevil Wrote:  It [the premise that momentum and kinetic energy still occur during the zero length of an instant] is backed up by centuries of empirical scientific evidence.
Are you sure? I am not.

Because of the conservation of energy, the number of occasions in which any scientist has stopped time is zero; therefore, the empirical evidence regarding the behaviour of things in a time-frozen universe amounts to zero.

We cannot freeze time, but we can freeze things by extracting as much of their kinetic energy as it is possible. Funnily enough, when things are frozen, their motion is reduced to a minimum. The way I see it, the notion of freezing already implies the loss of motion.

(28-04-2014 12:51 PM)Stevil Wrote:  If you think momentum and kinetic energy have all of a sudden gone then you need to account for that. Where did the energy go?
Energy is not a structure located somewhere in relation to other things; strictly speaking, energy cannot go anywhere because energy isn’t anywhere. It is material structures what are somewhere.

I happen to live in a time period when energy and matter are considered by many to be the same thing, but I am not convinced they are. In my possibly mistaken mind, it makes more sense to think of energy as yet another abstract notion that helps us understand how material structures store and exchange their motion and their tendency to move.

I think it is important to understand that there is a real universe consisting of matter arranged in space, and a virtual universe consisting of change happening over time. Both are inter-related because the latter happens as things in the former move, but it is useful to understand in what features they differ.

(28-04-2014 12:51 PM)Stevil Wrote:  Whose to say that the energy within our universe wasn't present prior to the big bang event?
Well, once again, I’d say it was the matter in the universe what was most likely present prior to the big bang event, but the total tendency of the universe to change (its energy) was most likely the same as it is now. In other words, I don’t think the big bang event implied the beginning of time.

(28-04-2014 12:51 PM)Stevil Wrote:  Whose to say that energy isn't an intrinsic property of nothing?
Well, I doubt so. I find it more likely that energy is an intrinsic property of matter. Matter exists, but nothing does not.

I don’t know; in my mind, all this makes sense. But it may be a load of bollocks, so if it doesn’t make sense in your mind, don’t worry too much about it.

Thanks again for the pleasure of chatting with you. Have a good one.
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28-04-2014, 05:19 PM
RE: Uncertainty… principle?
(28-04-2014 01:53 PM)living thing Wrote:  In fact, the way things don’t move when I capture only a brief moment of time does suggest that motion does not occur during a zero length instant.
This is contrary to the laws of physics.
Kinetic energy and momentum is still in effect thus instantaneous velocity can be calculated.
KE = 1/2.m.v^2
If you know KE and you know m then v is calculable.

There is no duration of time necessary in order to calculate v.
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28-04-2014, 05:49 PM (This post was last modified: 28-04-2014 06:06 PM by Hafnof.)
RE: Uncertainty… principle?
(28-04-2014 12:39 PM)living thing Wrote:  Do you think that an object can change its location or its orientation, in relation to some other object, during a time increment of zero units?

I'm not sure that zero units of time can actually exist in the real world. It may be that the smallest unit of time is not zero, but is instead the Planck time[1]. The smallest unit of distance might not be zero, but instead the Planck length[2]. At the quantum level there are also not really "objects" that have precise locations and orientations, but instead there are waves that have only imprecise location and orientation (this whole thread is about the uncertainty principle that describes this imprecision, is it not?) and events where some interaction or "collapse" has occurred... which themselves have an uncertainty in space and time.

I'm sceptical that you can (even theoretically) freeze the world in zero-sized units. I suspect that the smallest unit you can slice the world into in both space and time is determined by the Planck constant. This perhaps gives us enough wiggle to preserve momentum at even instantaneous (ie Planck length) scales of space and time. Alternatively, momentum such as spin could be another kind of property of quantum particles that we don't otherwise fully understand but is none the less present and describable even in this instantaneous image of the universe. As I say, at this level it is fundamental. There may be a deeper level where it has a clearer cause but for the moment we seem only to be able to say that at the quantum level it is a property particles intrinsically have.

More specifically, I suspect that if you were to obtain a slice of the universe that consists of zero units of time you would find it to be entirely empty as quantum particles won't be able to fit in this space - just as photons can't exist between two plates that are closer together than their wavelengths require. In the Casimir effect[3] we find that we can exclude photons from such a space in such a way as to cause a measurable force to be applied to two plates due to the difference in pressure between the zero photons that fit between them and the real photons that bombard the outside of the plates. I think your zero-time slice of the universe would likely have the same property of being empty due to particles not fitting into that short a unit of time.

(28-04-2014 01:53 PM)living thing Wrote:  
(28-04-2014 12:51 PM)Stevil Wrote:  If you think momentum and kinetic energy have all of a sudden gone then you need to account for that. Where did the energy go?
Energy is not a structure located somewhere in relation to other things; strictly speaking, energy cannot go anywhere because energy isn’t anywhere. It is material structures what are somewhere.

Here's a place I think you are going wrong. You think matter is different to energy, but it isn't. Matter is made of energy. Quarks (making up protons and neutrons), electrons, photons etc, these all behave the same way when you look at them closely. The only we we know how to describe them is as waves. Matter is intrinsically moving stuff at this quantum level. If there is no energy there is also no matter. You can't really stop matter at this level without destroying it.

[1] https://en.wikipedia.org/wiki/Planck_time
[2] https://en.wikipedia.org/wiki/Planck_length
[3] https://en.wikipedia.org/wiki/Casimir_effect

Give me your argument in the form of a published paper, and then we can start to talk.
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29-04-2014, 07:01 AM
RE: Uncertainty… principle?
Hello Stevil, how are you?

(28-04-2014 05:19 PM)Stevil Wrote:  
(28-04-2014 01:53 PM)living thing Wrote:  In fact, the way things don’t move when I capture only a brief moment of time does suggest that motion does not occur during a zero length instant.
This is contrary to the laws of physics.
Kinetic energy and momentum is still in effect thus instantaneous velocity can be calculated.
What exactly do you mean when you say that kinetic energy and momentum is still in effect during the “length” of a zero length instant? Do you mean that things still change their relative locations or orientations with respect to other things during that non-interval?

Ok, let me suggest an experiment you can perform, maybe with the help of some friends. You’ll need something moving at a fairly constant speed and several cameras each configured to take a photograph with a different exposure time. As the thing being photographed moves, take a picture with all cameras starting their exposure as simultaneously as possible; that's where your friends may be handy.

Once you have access to the images (don’t forget which one is which) try to measure the length of the trail produced by the moving object in each of the pictures. If its speed during the longest exposure time was indeed constant, you will notice that the lengths of the trails are proportional to the exposure times; the longer the photographed interval, the longer the trail. And the reason is obvious. Velocity is a magnitude that reflects how much an object’s relative location or orientation changes over a length of time; that is why it is expressed in units like miles per hour, radians per second, etc.

It is very easy to calculate the average velocity of a moving object over a length of time; you just need to divide the distance covered by the time taken, and the result is the value sought. Once we have that value, and presuming that no unbalanced forces act upon our object, we can use it to calculate where the object will be at any future instant, by multiplying the length of the interval between the present instant and the future instant, times the calculated velocity. The result is the distance the object will cover during that interval. Since the distance covered by a moving object is proportional to the duration of the considered interval, the lengths of the trails in the pictures are proportional to their exposure times, because each photograph shows a superposition of all the object’s locations between the beginning of the captured interval and the end.

If we choose our future instant to be our present instant, so that the duration of the interval between them is zero, the calculated distance covered is zero too; any defined value multiplied by zero equals zero. An object may have as much momentum and kinetic energy as you want, but, during the non-duration of an instant, it does not change its location nor its orientation; motion only happens over a non-zero period of time. And this is consistent with all the so-called laws of physics that you may wish to bring forward, because all measurements of motion and its derived magnitudes are expressed in relation to time intervals, not instants. Velocity reflects the change of location or orientation over time and it is often expressed in metres per second. Acceleration reflects the change in velocity over time and it is often expressed in metres per second per second, or metres per second squared. Energy is related to how material structures move, accelerate and decelerate, and it is often expressed in kilograms times metres squared per second squared.

To me, it seems obvious that momentum and kinetic energy are only in effect during a non-zero interval of time, but I may be wrong.

(28-04-2014 05:19 PM)Stevil Wrote:  KE = 1/2.m.v^2
If you know KE and you know m then v is calculable.
Yes, it is calculable. In our brains. That is why I describe instantaneous velocity as an abstraction in our minds that helps us understand the behaviour of things outside our minds.

(28-04-2014 05:19 PM)Stevil Wrote:  There is no duration of time necessary in order to calculate v.
Of course there is; your brain cannot perform those calculations instantly and no computer will give you an immediate answer because the execution of their programs always takes several clock cycles.

Do you really not see how there is an important difference between considering a durationless instant and a non-zero time interval? Well, if you don’t, maybe the difference is not there; I don’t want you to believe it. I’m just saying that, in my view, motion only happens over non-zero lengths of time, which is analogous to how matter only occurs over non-zero volumes of space. But I may be wrong, please don’t take my words as truths.

Thank you anyway for your perspective, it is always welcome. Have a great time!
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29-04-2014, 07:19 AM
RE: Uncertainty… principle?
Hello Hafnof, thank you for an informative contribution to this thread, and also for the interesting links provided.

(28-04-2014 05:49 PM)Hafnof Wrote:  
(28-04-2014 12:39 PM)living thing Wrote:  Do you think that an object can change its location or its orientation, in relation to some other object, during a time increment of zero units?
I'm not sure that zero units of time can actually exist in the real world. It may be that the smallest unit of time is not zero, but is instead the Planck time[1]. The smallest unit of distance might not be zero, but instead the Planck length[2].
Well, using the words as I use them, I am as sure as I can be about anything (i.e., not completely sure) that zero units of time cannot exist in the real world. The way I view things, time is not an object that is located somewhere in relation to anything; time happens in our minds as things change in and outside our brains.

It is a bit like considering a sunrise. Do sunrises exist? Well, no, they’re not objects located somewhere. Do sunrises occur out there? Well, not really. Sunrises occur in our minds as the planet on which we stand rotates about its geographical north-south axis; specifically, during the time while our nearest star appears (from our perspective on the surface) to rise above the horizon. But that is simply an illusion; the sun is not really rising above anything. Like time, sunrises happen in our minds.

If the Planck time is how long it takes light travelling in a vacuum to cover a distance of one Planck length, how long does it take for light travelling in a vacuum to cover half a Planck length? Moreover, how long does it take for light to cover no distance at all? I don't think it takes any time for things to not move. Motion happens over non-zero lengths of time.

Existence, however, only happens precisely during the “length” of a durationless instant. As soon as any non-zero interval of time lapses, the volumes that things occupy in relation to other things become imprecise, because things move. It may be that the slightest possible change takes a Planck time to develop, but what that suggests in my mind is that in no time, no change occurs.

(28-04-2014 05:49 PM)Hafnof Wrote:  At the quantum level there are also not really "objects" that have precise locations and orientations, but instead there are waves that have only imprecise location and orientation (this whole thread is about the uncertainty principle that describes this imprecision, is it not?) and events where some interaction or "collapse" has occurred... which themselves have an uncertainty in space and time.
In Akira Tonomura’s electron double slit experiment, each electron arrived to the detector as a tiny object with a fairly precise location shown on the screen. The wave-like behaviour only appeared over a relatively long period of time (two hours).

At the quantum level, what becomes fuzzy is our knowledge about an object’s precise structure, location and orientation, but that does not mean that the object’s precise structure, location and orientation is fuzzy; I find it sensible to draw a distinction between the abstract notions in our minds and the things outside our skulls.

(28-04-2014 05:49 PM)Hafnof Wrote:  I'm sceptical that you can (even theoretically) freeze the world in zero-sized units. I suspect that the smallest unit you can slice the world into in both space and time is determined by the Planck constant.
Which is probably why electron spin can be measured in half integers of the reduced Planck constant which, as its common name suggests, is smaller than the Planck constant.

I cannot fully freeze anything because there is no way to extract all of an object’s kinetic energy in a finite number of steps. In order for heat to flow from the object I am attempting to fully freeze to a different structure, my different structure needs to be colder than the object I am attempting to fully freeze; otherwise, heat will flow from my different structure to the object I am attempting to fully freeze. In order to achieve full freezing of an object, I need a fully frozen object to begin with.

Moreover, the universe taken as a whole cannot be frozen because once we consider the full set of structures, heat cannot flow from there to anything else; once we've taken into account everything, there is nothing else. Overall, change cannot be stopped from happening in the universe; time cannot be frozen.

But I can observe how the motion of things decreases as their temperature decreases, how the motion of thing decreases as the time intervals considered shorten, and try to fantasise about how the universe would behave if time could be frozen in a durationless instant. Both the freezing and the durationless instant suggest no motion at all; so the universe I picture would display no behaviour at all; every form of behaviour implies something moving in relation to something else. So this may be pure fantasy, but I don’t think things move during the non-duration of an instant.

(28-04-2014 05:49 PM)Hafnof Wrote:  More specifically, I suspect that if you were to obtain a slice of the universe that consists of zero units of time you would find it to be entirely empty as quantum particles won't be able to fit in this space - just as photons can't exist between two plates that are closer together than their wavelengths require. In the Casimir effect[3] we find that we can exclude photons from such a space in such a way as to cause a measurable force to be applied to two plates due to the difference in pressure between the zero photons that fit between them and the real photons that bombard the outside of the plates. I think your zero-time slice of the universe would likely have the same property of being empty due to particles not fitting into that short a unit of time.
Are you sure you are not confusing time with space?

Space is the context in which material structures appear; time is the context in which change appears. Both are contexts in which information appears, so we can consider spacetime as the context in which things exist and events happen, but that does not mean that space is time, or that time is space. Space reflects matter’s ability to move (things can move if there is empty space around them) whereas time reflects the fact that matter is constantly moving (things are constantly changing locations and orientations in relation to most other things).

When you say “obtain a slice of the universe that consists of zero units of time”, what exactly do you mean? A photograph may be seen as a slice of the universe approaching zero units of time (it may be measured in fractions of a second, close to zero) and if there is something the photograph lacks, that is change. Still pictures lack change but they still convey meanings through the location of things in the image; in order to convey change, you need moving pictures.

(28-04-2014 05:49 PM)Hafnof Wrote:  
(28-04-2014 01:53 PM)living thing Wrote:  Energy is not a structure located somewhere in relation to other things; strictly speaking, energy cannot go anywhere because energy isn’t anywhere. It is material structures what are somewhere.

Here's a place I think you are going wrong. You think matter is different to energy, but it isn't. Matter is made of energy.
Well, I may be wrong; I’ve never claimed I’m not. But are you willing to accept that you may be wrong too? Or do you think I am wrong because you think you are right?

I have read and heard many claims that matter is made of energy but I don’t take that notion as a truth because it doesn’t make sense in my mind. The notion of an object’s ability to exert a force on another object over a distance relies on the existence of both objects; if you have no objects, you have no ability to exert anything. I can understand existence without motion, but I cannot understand motion without existence.

(28-04-2014 05:49 PM)Hafnof Wrote:  Quarks (making up protons and neutrons), electrons, photons etc, these all behave the same way when you look at them closely.
That is misleading and also not true. It is misleading because objects at that level of structure behave quite differently if you look at them closely than they do if you don’t. It is also not true because the behaviour of different particles at that level of structure is different. The behaviour of an electron in an electric field, for example, is the opposite to that of a positron in the same electric field.

(28-04-2014 05:49 PM)Hafnof Wrote:  The only we we know how to describe them is as waves.
Not exactly; there is a different set of circumstances in which they can be described as particles. I don’t think the particle-wave duality means that there is only waves; that would be better called “the wave singularity”. I think it is more likely related to how particles describe the structure of the universe, whereas waves describe its behaviour.

(28-04-2014 05:49 PM)Hafnof Wrote:  Matter is intrinsically moving stuff at this quantum level.
Stuff? And what is that stuff? The universe is intrinsically moving stuff at every level of its structure, but only if stuff is a synonym for matter. So what is this stuff that moves if it is not matter? Abstract ability to exert forces over distances? Your claim sounds quite stringy to me, but I don’t believe in magic strings.

(28-04-2014 05:49 PM)Hafnof Wrote:  If there is no energy there is also no matter.
That is only if I accept the premise that matter is made of energy, but I am not sure about that premise.

(28-04-2014 05:49 PM)Hafnof Wrote:  You can't really stop matter at this level without destroying it.
Apparently, light pulses can be stopped without being destroyed and that may have practical applications in improving the efficiency of optical switching devices. If light pulses can be stopped without being destroyed, why should I think that matter cannot be stopped without destroying it?

I don’t know, I cannot say I truly know. I see things my way and I try to make sense of them, but if there is something I do know, I do know that I may be mistaken. So please don’t take my words as an attempt to convince you of anything. Similarly, I hope you don’t mind if, for now, I remain unconvinced by the view you’ve presented. I am not saying that you are wrong, I am saying that, for as long as I don’t understand how the notions you've described are true, I will not consider them as truths. But it may well be that I am just too stupid to understand them.

Nevertheless, I do appreciate the time you’ve already spent on this conversation. Thanks, and have fun!
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29-04-2014, 12:54 PM
RE: Uncertainty… principle?
(29-04-2014 07:01 AM)living thing Wrote:  Hello Stevil, how are you?

(28-04-2014 05:19 PM)Stevil Wrote:  This is contrary to the laws of physics.
Kinetic energy and momentum is still in effect thus instantaneous velocity can be calculated.
What exactly do you mean when you say that kinetic energy and momentum is still in effect during the “length” of a zero length instant? Do you mean that things still change their relative locations or orientations with respect to other things during that non-interval?
I mean that the energy needs to be accounted for.

(29-04-2014 07:01 AM)living thing Wrote:  To me, it seems obvious that momentum and kinetic energy are only in effect during a non-zero interval of time, but I may be wrong.
You are wrong because you are only considering what you can visually see, you are not accounting for the energy that is present.

(29-04-2014 07:01 AM)living thing Wrote:  
(28-04-2014 05:19 PM)Stevil Wrote:  KE = 1/2.m.v^2
If you know KE and you know m then v is calculable.
Yes, it is calculable.

(29-04-2014 07:01 AM)living thing Wrote:  
(28-04-2014 05:19 PM)Stevil Wrote:  There is no duration of time necessary in order to calculate v.
Of course there is;
Not there is not. All we need is KE and m then we can calculate v.
We are talking about freezing time in the picture, the system that we are measuring. We aren't talking about freezing time in our brain or our calculator when we retrospectively analyse the picture.
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29-04-2014, 02:17 PM (This post was last modified: 29-04-2014 02:26 PM by living thing.)
RE: Uncertainty… principle?
Hello Stevil, how is it going? I hope it is going great, thanks for coming back.

Can I please ask you how you view this conversation? Not the content, but the conversation itself. Is it a competitive debate where one participant must be right and the other must be wrong? If that is the case I want to be the wrong guy, because every time I’m wrong, I get to learn.

But I view this conversation as an exchange of perspectives; I try to learn, through your words, what the universe appears to be from your view, and in exchange I try to describe what it appears to be from my point of view. I like learning other perspectives because the combination of different subjective perspectives often yields objective notions, but I also keep in mind that any idea suggested by anyone including myself is susceptible of being mistaken, so once the exchange happens, we can each try to make the most of the notions described, but there is no need for either of us to expect that the other part will be convinced by our views.

I hope that we can conduct this conversation as an exchange of perspectives, not as a competitive debate, because I do have better things to do with my finite time than arguing with a random stranger connected to the same computer network I am. There is no need to resort to inelegant tricks such as extracting sentences out of their context so that they seem to convey a different notion than intended.

(29-04-2014 12:54 PM)Stevil Wrote:  I mean that the energy needs to be accounted for.
Motion, and therefore momentum and kinetic energy, only appear over non-zero lengths of time. But potential energy sort of appears in space, although it does not occupy any volume. An energy field can be viewed as the set of locations around an object where the behaviours of other objects are affected significantly and, as such, it is something that “appears” in space, although it doesn’t exist because fields, unlike existing material structures, can overlap the volumes they “occupy”; a specific location in space can be part of two different energy fields at the same time, but not contained in two different material structures at the same time.

So I guess we may consider that, at every durationless instant, all energy is potential. An object that “has” instantaneous velocity has the potential to move after a non-zero length of time, but that only becomes actual motion over a non-zero length of time; during a zero length instant, it is only potential energy.

Would that satisfy the need to account for energy?

(29-04-2014 12:54 PM)Stevil Wrote:  You are wrong because you are only considering what you can visually see, you are not accounting for the energy that is present.
Well, I did consider the “present” energy when I said that I would need to subtract potential energies from structures in order to freeze time, and that had nothing to do with my vision.

(29-04-2014 12:54 PM)Stevil Wrote:  
(29-04-2014 07:01 AM)living thing Wrote:  Yes, it is calculable. In our brains.

(29-04-2014 12:54 PM)Stevil Wrote:  Not there is not [a duration of time necessary in order to calculate v]. All we need is KE and m then we can calculate v…
… after a few computing cycles, either in our brains or in our calculators. Even if you manage to perform all the calculations in parallel, which is unlikely because some steps may depend on the results of previous steps, you will need at least one clock cycle (a measurement of wave period, expressed in non-zero time units) in order to perform the calculation. I don’t think that your claim that there is not a duration of time necessary in order to calculate v is supported by evidence.

But maybe it is, so please don’t take this as an attempt to claim that you are wrong; it is just that I don’t believe that you are right. But I might be wrong myself, so please do not be offended by my disbelief.

I thank you again for your new contribution to the thread, although if you expect me to be convinced by you telling me that I am wrong, I can only recommend you patience, I’m not the sort of person who believes whatever someone says on an internet forum; I draw my limited knowledge from many other sources.

Have a good one!

(Edit: added missing word)
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29-04-2014, 03:51 PM
RE: Uncertainty… principle?
(29-04-2014 07:19 AM)living thing Wrote:  If the Planck time is how long it takes light travelling in a vacuum to cover a distance of one Planck length, how long does it take for light travelling in a vacuum to cover half a Planck length? Moreover, how long does it take for light to cover no distance at all? I don't think it takes any time for things to not move. Motion happens over non-zero lengths of time.

Right.. but the problem is that that's a fundamentally incoherent question according to modern physical theories.

Quantum mechanics means that quantisation is inescapable.

(29-04-2014 07:19 AM)living thing Wrote:  Existence, however, only happens precisely during the “length” of a durationless instant. As soon as any non-zero interval of time lapses, the volumes that things occupy in relation to other things become imprecise, because things move. It may be that the slightest possible change takes a Planck time to develop, but what that suggests in my mind is that in no time, no change occurs.

That is in fact precisely how time is defined: separation between discrete observable states.

A thought experiment such as yours may be of some interest but need not - and here does not - bear any direct correspondence to reality.

(29-04-2014 07:19 AM)living thing Wrote:  At the quantum level, what becomes fuzzy is our knowledge about an object’s precise structure, location and orientation, but that does not mean that the object’s precise structure, location and orientation is fuzzy; I find it sensible to draw a distinction between the abstract notions in our minds and the things outside our skulls.

... But that's fallacious.

There are no hidden variables. There is no reason to presuppose any "additonal" information to exist beyond the theoretical limitations as we understand them.

It is not that knowledge of quantum-scale positions of, say, particles has limitations, although that is true for different reasons.

It is that naive/classical phenomena do not exist. They are artifacts of (limited, human) perception at certain scales of interaction.

(29-04-2014 07:19 AM)living thing Wrote:  Which is probably why electron spin can be measured in half integers of the reduced Planck constant which, as its common name suggests, is smaller than the Planck constant.

The Planck "constant" - with many others - is simply a ratio between pre-existing units of measurement.

In this case between units of energy and units of frequency.

(reduced meaning merely the addition of a 1/2π factor)

(29-04-2014 07:19 AM)living thing Wrote:  I cannot fully freeze anything because there is no way to extract all of an object’s kinetic energy in a finite number of steps. In order for heat to flow from the object I am attempting to fully freeze to a different structure, my different structure needs to be colder than the object I am attempting to fully freeze; otherwise, heat will flow from my different structure to the object I am attempting to fully freeze. In order to achieve full freezing of an object, I need a fully frozen object to begin with.

You may have heard of a thing called zero-point energy.

A quantum oscillator has non-zero ground energy. This means that it is not possible to remove all its energy. As an idealised experimental apparatus we can conceive of an infinitely capable heat reservoir and refrigerator. That doesn't matter.

Because such a system can't have zero energy, it can't "stop" moving, even in the zero-temperature limit.

(29-04-2014 07:19 AM)living thing Wrote:  Are you sure you are not confusing time with space?

Space is the context in which material structures appear; time is the context in which change appears. Both are contexts in which information appears, so we can consider spacetime as the context in which things exist and events happen, but that does not mean that space is time, or that time is space. Space reflects matter’s ability to move (things can move if there is empty space around them) whereas time reflects the fact that matter is constantly moving (things are constantly changing locations and orientations in relation to most other things).

That's... not quite valid either. Most interactions are - at least in some ways - symmetric in space and time coordinates. This is a necessary consequence of the general-relativistic viewpoint.

(29-04-2014 07:19 AM)living thing Wrote:  I have read and heard many claims that matter is made of energy but I don’t take that notion as a truth because it doesn’t make sense in my mind.

That's never a good way to start.
Tongue

(29-04-2014 07:19 AM)living thing Wrote:  The notion of an object’s ability to exert a force on another object over a distance relies on the existence of both objects; if you have no objects, you have no ability to exert anything. I can understand existence without motion, but I cannot understand motion without existence.

That's really a false dichotomy.

E=MC2, after all.

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29-04-2014, 06:23 PM (This post was last modified: 29-04-2014 06:34 PM by living thing.)
RE: Uncertainty… principle?
Hello cjlr, it’s nice to see you here again; your contributions are always useful. I don’t think we disagree entirely, although it is obvious that we do have different perspectives, and that is great. Different perspectives are the ones you can learn from; if your perspective were exactly the same as mine, I would hardly be able to learn anything new from our exchange of views.

Please excuse me if some of the clarifications I may ask from you seem ignorant; we are dealing with complex topics in a language that is not my native language. I beg for your patience.

(29-04-2014 03:51 PM)cjlr Wrote:  
(29-04-2014 07:19 AM)living thing Wrote:  If the Planck time is how long it takes light travelling in a vacuum to cover a distance of one Planck length, how long does it take for light travelling in a vacuum to cover half a Planck length? Moreover, how long does it take for light to cover no distance at all? I don't think it takes any time for things to not move. Motion happens over non-zero lengths of time.

Right.. but the problem is that that's a fundamentally incoherent question according to modern physical theories.
Are you saying that the question “how long does it take for things to not move?” is fundamentally incoherent?

(29-04-2014 03:51 PM)cjlr Wrote:  Quantum mechanics means that quantisation is inescapable.
Well I did concede that the Planck time might be the time taken for the slightest change to develop, didn’t I? I am not trying to escape quantisation. In fact, I seem to be alone in these threads at suggesting that matter might be quantised too; there might be a simplest level of material structure. Is there a simplest level of material structure? I don’t know, I just wouldn’t be surprised if there were.

(29-04-2014 03:51 PM)cjlr Wrote:  
(29-04-2014 07:19 AM)living thing Wrote:  Existence, however, only happens precisely during the “length” of a durationless instant. As soon as any non-zero interval of time lapses, the volumes that things occupy in relation to other things become imprecise, because things move. It may be that the slightest possible change takes a Planck time to develop, but what that suggests in my mind is that in no time, no change occurs.

That is in fact precisely how time is defined: separation between discrete observable states.
Good! I’m glad I’ve managed to get something apparently right. Although I wouldn’t be too sure about it.

(29-04-2014 03:51 PM)cjlr Wrote:  A thought experiment such as yours may be of some interest but need not - and here does not - bear any direct correspondence to reality.
Does it not bear any correspondence to reality the fact that things lose motion as they are progressively frozen? Does it not bear any correspondence to reality that the trails of moving objects as captured in photographs are proportional to the exposure times?

(29-04-2014 03:51 PM)cjlr Wrote:  
(29-04-2014 07:19 AM)living thing Wrote:  At the quantum level, what becomes fuzzy is our knowledge about an object’s precise structure, location and orientation, but that does not mean that the object’s precise structure, location and orientation is fuzzy; I find it sensible to draw a distinction between the abstract notions in our minds and the things outside our skulls.

... But that's fallacious.

There are no hidden variables. There is no reason to presuppose any "additonal" information to exist beyond the theoretical limitations as we understand them.
I’m sorry, what exactly is fallacious? How have I mentioned hidden variables? What “additional” information existing beyond theoretical limitations as currently understood am I presupposing?

(29-04-2014 03:51 PM)cjlr Wrote:  It is not that knowledge of quantum-scale positions of, say, particles has limitations, although that is true for different reasons.
So is it, or is it not?

(29-04-2014 03:51 PM)cjlr Wrote:  It is that naive/classical phenomena do not exist. They are artifacts of (limited, human) perception at certain scales of interaction.
My view is definitely not the classical and if you find it naïve you probably have your reasons, but in any case I agree in that phenomena do not exist; I would say that they occur (those that occur, of course. Phenomena that do not occur, such as creation of universes, do not occur).

(29-04-2014 03:51 PM)cjlr Wrote:  
(29-04-2014 07:19 AM)living thing Wrote:  Which is probably why electron spin can be measured in half integers of the reduced Planck constant which, as its common name suggests, is smaller than the Planck constant.

The Planck "constant" - with many others - is simply a ratio between pre-existing units of measurement.

In this case between units of energy and units of frequency.

(reduced meaning merely the addition of a 1/2π factor)
I thank you for your clarifications, although Hafnof seemed to be considering the Planck constant as somehow the smallest thing, and I was simply trying to point out how even smaller notions such as half the reduced Planck constant can be meaningful.

(29-04-2014 03:51 PM)cjlr Wrote:  
(29-04-2014 07:19 AM)living thing Wrote:  I cannot fully freeze anything because there is no way to extract all of an object’s kinetic energy in a finite number of steps. In order for heat to flow from the object I am attempting to fully freeze to a different structure, my different structure needs to be colder than the object I am attempting to fully freeze; otherwise, heat will flow from my different structure to the object I am attempting to fully freeze. In order to achieve full freezing of an object, I need a fully frozen object to begin with.

You may have heard of a thing called zero-point energy.

A quantum oscillator has non-zero ground energy. This means that it is not possible to remove all its energy. As an idealised experimental apparatus we can conceive of an infinitely capable heat reservoir and refrigerator. That doesn't matter.

Because such a system can't have zero energy, it can't "stop" moving, even in the zero-temperature limit.
Of course any kind of oscillator has non-zero ground energy; if it had no energy, it wouldn’t be an oscillator.

So I think we basically agree; I can neither fully freeze an object nor stop the universe from changing. Although I don't agree with calling it zero-temperature limit if the system cannot have zero energy. The system cannot stop moving during any interval of time chosen, but that does not mean that motion occurs during an instant. Motion during a zero-duration instant would involve infinite velocities.

(29-04-2014 03:51 PM)cjlr Wrote:  
(29-04-2014 07:19 AM)living thing Wrote:  Are you sure you are not confusing time with space?

Space is the context in which material structures appear; time is the context in which change appears. Both are contexts in which information appears, so we can consider spacetime as the context in which things exist and events happen, but that does not mean that space is time, or that time is space. Space reflects matter’s ability to move (things can move if there is empty space around them) whereas time reflects the fact that matter is constantly moving (things are constantly changing locations and orientations in relation to most other things).

That's... not quite valid either. Most interactions are - at least in some ways - symmetric in space and time coordinates. This is a necessary consequence of the general-relativistic viewpoint.
What does that symmetry in space and time coordinates mean, and how have I questioned it? Then again, I try not to take any notion as a given truth, so if I turn out to be questioning the general-relativistic viewpoint, so be it, I don’t mind. I don’t think there are unquestionable truths.

It may well be that I am simply too stupid to understand the general-relativistic viewpoint, of course, but one problem I have often encountered when reading about it is that books are not interactive containers of knowledge; you can ask a book for clarifications, but it won’t answer. People are interactive containers of knowledge, but when I’ve spoken about the subject with people, I have often found that they resorted to reading the books out loud, which didn’t help. I understand that your time is probably limited, and I’d hate asking you to spend it on my education, so I’ll simply suggest something you can do if you find it worth the effort. Since you obviously know a lot about it, and for the benefit of everyone reading this online forum, you could begin a series of interactive threads explaining the general-relativistic viewpoint; a series of threads where the rest of us can ask you questions until we understand it.

If you spend any time even considering the idea, I already thank you for it.

(29-04-2014 03:51 PM)cjlr Wrote:  
(29-04-2014 07:19 AM)living thing Wrote:  I have read and heard many claims that matter is made of energy but I don’t take that notion as a truth because it doesn’t make sense in my mind.

That's never a good way to start.
Tongue
Are you really suggesting that the good way to start is taking notions as truths, even if they don’t make sense? And why shouldn’t I believe in gods, then? They don't make sense, but following your advice...

(29-04-2014 03:51 PM)cjlr Wrote:  
(29-04-2014 07:19 AM)living thing Wrote:  The notion of an object’s ability to exert a force on another object over a distance relies on the existence of both objects; if you have no objects, you have no ability to exert anything. I can understand existence without motion, but I cannot understand motion without existence.

That's really a false dichotomy.

E=MC2, after all.
Yes, but you are probably aware that the M in E=MC2 does not stand for “matter”, it stands for “mass”, aren't you? Mass is not matter; mass is another abstract implication conveyed by the existence of matter.

I presume that you are describing my last sentence as a false dichotomy (“I can understand existence without motion, but I cannot understand motion without existence”). And seeing how you bring E=MC2 as an additional possibility, thus breaking the dichotomy, I guess that the third option is that existence can somehow transform into motion and vice versa. If that is not what you mean, I kindly ask you to please rephrase your objection so that I can properly understand it. Meanwhile, I can rephrase what I meant; maybe I chose a poor way to express it.

I can find meaning in existence by itself, without considering anything but material structures occupying non-zero volumes of space, each located at some distance and in some direction from each other. Things may interact over time as a result of their location in space, but their interaction is not a requirement in order for them to be somewhere in relation to each other.

I can find meaning in change when I view it in terms of matter; change happens when material structures move and rotate in relation to one another. But I cannot find meaning in change if I consider matter to disappear; if material structures are not there, what changes in relation to what? What is motion if not something's change in location or orientation? In order for something to move, there first needs to be something. If I remove the notion of matter from my mental model, the notion of energy disappears too.

But I don’t have any conceptual problem removing the notion of energy from my mental model. If I had two balls… hold on, I do have two balls. If I had two perfectly rigid spherical material structures with no electrical charge, in contact so that their gravitational potential energy were zero, and with no kinetic energy either, they would just not move. Ok, I can understand that.

I don’t know. As I’ve said a few times already, I cannot say I truly know. My view may be terribly naïve, and I may just be an ignorant trying but failing to understand the complex universe around me; I don’t want you to believe anything that I’ve said. I do thank you for pointing out fallacies in my arguments, even though I still don’t quite understand how my arguments are fallacious. But I hope that you will be kind enough to explain how they are in a language that I can comprehend.

Thanks again for your valuable contribution, cjlr. It is a pleasure to see your nickname in this thread.

Have a great time!

(Edit: fixed typo)
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