Time and such
Whatever time may be, it seems to involve duration and simultaneity, neither of which are arbitrary ramblings, but would have to be accounted for by (or included in) any theory of time:
People sure have come up with a few ideas about time over the years (pun intended):
An aggregate of duration and simultaneity, an entropy gradient, an irreducible or basic aspect of the universe, that we wish to quantify with clocks, subject to relativity, …? Whether time is fundamental or not, duration and simultaneity will have to be taken into account.
For context, let’s just briefly examine non-spatiotemporality (like abstracts perhaps):
Causation is roughly uni-directional interaction, or uni-directional aspects thereof — what we find as related, temporally ordered events. Causes and effects are events, and events are subsets of changes — they occur (in context).
Suppose we were to reduce time/temporality to something else, then how do we account for that something else? There’s an analogy to be found in the diallelus, regarding ontological reduction. Can there be answers that do not admit further questions, even in principle? Doesn’t really seem like it, in which case we just find ourselves on some indefinite path of inquiry. [sup]wikipedia, iep[/sup]
It may be possible to argue that “time does not pass” for a free photon, or that a photon does not age, in some sense, by moving at light speed. Indeed, photons are thought to not decay. They can still interact, however, which can be a drastic change in reference frame. Does this lend credence to Shoemaker’s odd thought experiment?
There’s also a linguistic oddity related to time. Time versus existence: Did/does time exist or was/is existence temporal? Expressing temporality in tensed language can be challenging. The term “to exist” also has past tense — our language can express things existing tensed — did exist, do exist, may yet come to exist. What, then, about time itself? Something’s fishy. Well, at least some things exist for some duration only, like processes, like dawn to dusk. But time itself would perhaps have to be referenced, or characterized, tense-less. Either way, we shouldn’t let our linguistic practices bewitch us (cf Wittgenstein). We have (possibly confusing) double-temporal proposition like “it is true now, that it rained the other day”. Contemporary cosmology supposes that time is an aspect of the universe, among others. The past was, the present is, and a future may yet come to be. The past already “solidified”, the future has not, and the present divides them.
Presentism and the A-series may lead to, or express, a form of idealism (philosophical, not political), and seems kind of inadequate. Process philosophy has more going for it.
On the other hand, eternalism and the B-theory seem to lack what we experience indexically, and so is incomplete in some sense. There’s no privileged “right now” included, at least not without adding it to the model. But once I’m gone, I could be characterized, in part, as a 4 dimensional “blob” (in lack of a better term), my connected spatiotemporal locales.
The growing block universe has a kind of intuitive appeal, and is a move from the block universe towards accounting more closely for a privileged now, albeit subject to some critique (like much else). Does the growing block already presuppose time, and hence cannot be used for setting out a model or definition thereof? Maybe, maybe not.
Relativity is apparently compatible with eternalism and the B-theory, which may be inherent in how such theories are formed. It’s intended that no particular “now” is all that’s modeled; the descriptive power is exactly the independence of a special “now”. Relativity is commonly said to describe a non-Euclidean geometry of 4 dimensional spacetime, and operates on something akin to a block universe, but that seems inherent in how no particular “location” (like the indexical “here-now”) has a special status.
[quote=https://plato.stanford.edu/entries/time/#McTArg](An odd but seldom noticed consequence of McTaggart's characterization of the A series and the B series is that, on that characterization, the A series is identical to the B series. For the items that make up the B series (namely, moments of time) are the same items that make up the A series, and the order of the items in the B series is the same as the order of the items in the A series; but there is nothing more to a series than some specific items in a particular order.)[/quote]
Sometimes there’s a (possibly subtle) misunderstanding of eternalism, or a block universe, in that the universe is said to be frozen, static, something like that. This is inaccurate, however, since change already is modeled along the temporal axis. On eternalism, or the block universe, there “is” still time (— by the way, notice the present tense “is” here — it’s misleading due to our language). Claiming that the past exists now is incoherent. Should a future come to pass, then that’s what the block model is supposed to have (thereby also separating ontology and epistemology). Time is one of the dimensions, and the (rest of the) universe is not static, since it changes along the temporal axis. The part that’s “incomplete” (in lack of a better word) is just that no particular “now” is privileged. Rather, the model includes any “now” on equal footing, if you will, and so does not privilege our current, indexical, experienced, present now (without the quotes). And that makes perfect sense for models like relativity, where we want descriptions that hold for any “now”.
[quote=Delmore Schwartz, Calmly We Walk Through This April’s Day (1938)]Time is the fire in which we burn.[/quote]
[quote=Tolian Soran, Star Trek: Generations (1994)]They say time is the fire in which we burn.[/quote]
________
- duration: it takes time to get to work in the morning
- simultaneity: we get to work about the same time in the morning, as agreed prior
People sure have come up with a few ideas about time over the years (pun intended):
- Zeno: motion is illusory
- Aristotle, Hume: no change implies no time (an empirical perspective)
- Kant: time and space are a priori (pre)conditions for all experience
- McTaggart: bah, smoke and mirrors, nothing but illusion and humbug
- Robb: time is a causal dimension of the world
- Shoemaker: time without change is conceivable (and logically consistent)
- A scientific approach: time is a (measurable) quantity of any kind of change
An aggregate of duration and simultaneity, an entropy gradient, an irreducible or basic aspect of the universe, that we wish to quantify with clocks, subject to relativity, …? Whether time is fundamental or not, duration and simultaneity will have to be taken into account.
For context, let’s just briefly examine non-spatiotemporality (like abstracts perhaps):
- Suppose x is defined as not spatial, “outside of space”. Well, then obviously x is nowhere to be found. And x cannot have any extent, volume, area, length, or the likes, not even zero-dimensional (like a mathematical singularity).
- Suppose x is defined as atemporal, “outside of time”. Well, then there can be no time at which x exists. And there can be no duration involved, x cannot change, or be subject to causation, cannot interact, and would be rather inert.
Causation is roughly uni-directional interaction, or uni-directional aspects thereof — what we find as related, temporally ordered events. Causes and effects are events, and events are subsets of changes — they occur (in context).
Suppose we were to reduce time/temporality to something else, then how do we account for that something else? There’s an analogy to be found in the diallelus, regarding ontological reduction. Can there be answers that do not admit further questions, even in principle? Doesn’t really seem like it, in which case we just find ourselves on some indefinite path of inquiry. [sup]wikipedia, iep[/sup]
It may be possible to argue that “time does not pass” for a free photon, or that a photon does not age, in some sense, by moving at light speed. Indeed, photons are thought to not decay. They can still interact, however, which can be a drastic change in reference frame. Does this lend credence to Shoemaker’s odd thought experiment?
There’s also a linguistic oddity related to time. Time versus existence: Did/does time exist or was/is existence temporal? Expressing temporality in tensed language can be challenging. The term “to exist” also has past tense — our language can express things existing tensed — did exist, do exist, may yet come to exist. What, then, about time itself? Something’s fishy. Well, at least some things exist for some duration only, like processes, like dawn to dusk. But time itself would perhaps have to be referenced, or characterized, tense-less. Either way, we shouldn’t let our linguistic practices bewitch us (cf Wittgenstein). We have (possibly confusing) double-temporal proposition like “it is true now, that it rained the other day”. Contemporary cosmology supposes that time is an aspect of the universe, among others. The past was, the present is, and a future may yet come to be. The past already “solidified”, the future has not, and the present divides them.
Presentism and the A-series may lead to, or express, a form of idealism (philosophical, not political), and seems kind of inadequate. Process philosophy has more going for it.
On the other hand, eternalism and the B-theory seem to lack what we experience indexically, and so is incomplete in some sense. There’s no privileged “right now” included, at least not without adding it to the model. But once I’m gone, I could be characterized, in part, as a 4 dimensional “blob” (in lack of a better term), my connected spatiotemporal locales.
The growing block universe has a kind of intuitive appeal, and is a move from the block universe towards accounting more closely for a privileged now, albeit subject to some critique (like much else). Does the growing block already presuppose time, and hence cannot be used for setting out a model or definition thereof? Maybe, maybe not.
Relativity is apparently compatible with eternalism and the B-theory, which may be inherent in how such theories are formed. It’s intended that no particular “now” is all that’s modeled; the descriptive power is exactly the independence of a special “now”. Relativity is commonly said to describe a non-Euclidean geometry of 4 dimensional spacetime, and operates on something akin to a block universe, but that seems inherent in how no particular “location” (like the indexical “here-now”) has a special status.
[quote=https://plato.stanford.edu/entries/time/#McTArg](An odd but seldom noticed consequence of McTaggart's characterization of the A series and the B series is that, on that characterization, the A series is identical to the B series. For the items that make up the B series (namely, moments of time) are the same items that make up the A series, and the order of the items in the B series is the same as the order of the items in the A series; but there is nothing more to a series than some specific items in a particular order.)[/quote]
Sometimes there’s a (possibly subtle) misunderstanding of eternalism, or a block universe, in that the universe is said to be frozen, static, something like that. This is inaccurate, however, since change already is modeled along the temporal axis. On eternalism, or the block universe, there “is” still time (— by the way, notice the present tense “is” here — it’s misleading due to our language). Claiming that the past exists now is incoherent. Should a future come to pass, then that’s what the block model is supposed to have (thereby also separating ontology and epistemology). Time is one of the dimensions, and the (rest of the) universe is not static, since it changes along the temporal axis. The part that’s “incomplete” (in lack of a better word) is just that no particular “now” is privileged. Rather, the model includes any “now” on equal footing, if you will, and so does not privilege our current, indexical, experienced, present now (without the quotes). And that makes perfect sense for models like relativity, where we want descriptions that hold for any “now”.
[quote=Delmore Schwartz, Calmly We Walk Through This April’s Day (1938)]Time is the fire in which we burn.[/quote]
[quote=Tolian Soran, Star Trek: Generations (1994)]They say time is the fire in which we burn.[/quote]
________
- Heraclitus (Wikipedia article), “panta rhei”, “no one ever steps in the same river twice”
- Parmenides (Wikipedia article), timeless existence
- Time (Wikipedia article)
- Time (Internet Encyclopedia of Philosophy article)
- Time (Stanford Encyclopedia of Philosophy article)
- Temporal logic (Wikipedia article)
- Arrow of time (Wikipedia article)
Comments (116)
Comments welcome.
It seems to me that for there to be no change the universe would have to be completely empty - always and everywhere, so no quantum particles popping in and out of existence. If it contains even one photon or particle then there is change, since matter is energy is waves, and waves involve vibration, which is change.
If time without change is only possible in an empty universe, what could it mean to say that time 'exists' in such a universe? It seems an empty notion, which is kind of appropriate.
I thought it had more to do with entropy? Our universe starts out in an extremely low entropy state for some reason, and is headed toward maximum entropy a long time from now. Once it reaches the maximum, the system can't be said to be changing in any meaningful way. The laws of physics are time-reversal, so anything popping in and out or waving has no direction.
That's my limited understanding of the directionality of time.
What does the "is" mean then, if not that it exists in the present tense? Either something is, was, or will exist so in what other way is the block universe said to "exist"?
Quoting jorndoe
Yep, that is certainly logically impossible, but that may just be the wrong way to say it. What if we instead say that the "Big Bang exists now" or "Napoleon exists now"? Instead of saying that these events and objects exist "in the past" and that the past currently exists, we just cut out the middleman. IMO, there is no conceptual incoherency in saying that.
I'll offer my opinion. Physical change without time is not logically possible, but time without physical change is.
Imagine that we divide time into shorter and shorter durations. At some point we reach a duration of time which is as short as is possible due to the limitations of physical change. This is the shortest possible duration of time in which physical change can occur. However, we can still imagine a shorter period of time simply by dividing that shortest period of time, within our minds.
But is this shorter than the shortest period of time (according to physical limitations) imaginary or real? Suppose that a physical change occurs which takes the shortest possible period of time according to the physical limitation. This time duration is t1 to t2, and during this time the change occurs. The change itself cannot be divided, it is the quickest possible change. So at t1 Y exists, and at t2 Z exists, and this is described as a quantum of change.
Now, something necessarily exists as a medium between Y and Z, to account for the difference between them. We cannot say that there is a physical activity such as a motion, which is Y changing to Z, because this motion would be itself divisible into parts. The physical activity is already described as one moment there is Y and the next moment Z, and an intermediate motion is not possible. Therefore we can conclude that the only thing which happens between Y and Z is that time passes. Y and Z are different states with no motion or physical activity intermediary between them. Yet there must be something intermediary to account for the difference between Y and Z. This intermediary is time itself. Therefore it is not only possible that time passes without physical change, but it is a necessary conclusion.
This might be true. But it might also be possible that the intermediary to account for the difference in time is the change from Y to Z so is this a valid argument?
If you are considering that possibility, then you have misunderstood the argument. I realized that this could be a problem, and tried to word it to avoid that problem. Think of it this way. Imagine that the change is a motion, an object moves from location Y to location Z. Because it has been stipulated that this is the shortest possible change, it is impossible that the object traverses a mid way point, say X, because this would imply that the object traverse YX then XZ, and the possibility of this this has been denied. There cannot be a describable intermediary between Y and Z without contradicted the premise that the change from Y to Z is the smallest possible.
So what we have here is a unit of change, a quantum, which is indivisible. However, from one state to the next, from Y to Z, time passes. There is nothing which is changing while this time is passing, or else we'd be able to describe that shorter change, occurring between Y and Z, but the change from Y to Z has already been designated as the shortest.. There is position Y, then there is position Z, which are two distinct positions. There is no physical change between these two, only time.
Try this. Let's say that when change occurs, object A changes to become object B. Something happens in between, and this is "the change". We could say that during the change, object A becomes C then becomes B. But then we have a change between A and C, as well as between C and B. To account for these changes, we could place D between A and C, and E between C and B. As you can see, in this way we would face infinite regress.
So we can make the assumption that there is a smallest possible change, to put an end to the infinite regress. This is supported by the limitations of material existence. So if that smallest possible change is denoted as the change of A to B, then we cannot assume any describable material existence between A and B, and all we are left with between A and B, is time passing. And time is necessarily passing to account for the fact that at one moment A is the case, and the next moment, B is the case. But no material change has occurred until B is the case.
A lifetime studying quantum mechanics has convinced Bernard d'Espagnat that the world we perceive is merely a shadow of the ultimate reality
Sounds like Plato. But Plato didn't need quantum mechanics to come to this conclusion, he just analyzed all the other sophistry going on.
This is not necessary. Time could be discrete, like the integers, or like popes.
Change can exist as purely mental events without space it seems to me, that is, it's certainly logically possible.
I think it goes deeper than that. Our concept of time is basically derived from our understanding of change. The fact is, if we did not perceive change in the world then we wouldn't have come up with this notion of a flow of time. Similarly, I don't think we can make sense of space either in a world without any physical objects. So to try, like Shoemaker does, to separate time from change and isolate one from the other sounds wrongheaded.
There is a problem with assuming a discrete time though. This is because we experience a continuous time, so we have nothing but arbitrary points in time according to our experience. If we want to understand a discrete time it requires that there are points of division within time itself. So the problem is to find something real which differentiates one quantum of time from another.
So suppose we have our units of change, Y and Z, and each one indicates a quantum of time. Time passes within Y, and within Z, and no time passes between Y and Z. This is opposed to the scenario I described, in which Y and Z were particular states and time passes in between these different states. Now under your proposed scenario, physical change is occurring at Y and at Z, but there is a necessary division between Y and Z, which separates one quantum of time from another. How could this be possible, and what could it look like? If it is a point when no time passes, what could that mean? Y and Z would necessarily be contiguous, but what could separate them? We can't represent it as a stoppage in physical activity, because this would mean that time passes here with no activity. So all we have is physical activity at Y and at Z with an arbitrary boundary between them.
The boundary between two discrete units of time would necessarily be arbitrary and therefore the discreteness of time would just be an arbitrary assumption. The problem is that we do not know of anything which could act as the boundary, or divisor, between one unit of time and another. If you posit a period of time which is designated non-time, to divide time into units, then what is that non-time other than time passing with no change occurring? Then we are back to the other position, of time passing with no change occurring. So once you start to talk about reality existing as quanta, it is necessary to assume time passing with no physical change occurring. And if quanta are real, then it is necessary to assume time passing without any physical change occurring, because this is a necessary condition for real quanta. The other way, discrete time, ends up with arbitrary divisions, and not real quanta.
Is there a difference between saying that change cannot be isolated from time and time cannot be isolated from change? It seems they express the same thing, that we cannot have one without the other, no?
As I explained, when you analyze this proposition there is nothing to make the boundaries between one frame and the next. So any such experience of time would need to consist of still frames of spatial (material) existence. But that just brings us back to my original description, in which Y and Z are the still frames of material existence, and time passes between them.
If Y and Z consist of active frames within which there is a quantum of time, then there is nothing to separate Y from Z. We can't posit a time with no time because this is contradictory. So Y and Z must be described as contiguous units of time, with a point of separation. But that point of separation is just posited by us, as an arbitrary point in time. It is not a real separation, because we can't posit a "non-time" to make a real separation. Then Y and Z just are two parts of a continuous time, arbitrarily divided. The quanta are not real. To produce a model with real quanta, and a real experience of existence as a movie, we need to consider material still frames with time passing in between each frame. This implies time passing without any material change, in this intermediary period..
Although the physics of time includes the idea of space, that is, time is a dimension of space, I don't think space is a necessary feature of time. For example, we experience time or change in dreams, but there is no spacial component. One could also imagine a mind or minds existing quite apart from space, and yet we could still experience a change in thoughts or experiences within the mind.
Yeah, that was how I read your "Change is analytic to time". That was what I'm saying essentially, but it seemed like you were inclined to disagree for some reason which is why I asked.
What about time simply being a measurement of change? That is what "duration" is - a measurement of change using other simultaneous change to compare it to. The time, or duration, it takes to get to work is the amount of change that happens on the face of a clock, simultaneously. The little hand moves from the 8 to the 9 (about 1 hour) while you are driving to work and sitting in traffic. You can't measure change, if the other change (the measuring stick) isn't happening simultaneously with the change you are measuring.
To say, "Time moves slowly" is actually saying that there hasn't been much change happening. Time seems to move slowly when we experience less change, as opposed to more change. This is why it seems like a long time has passed when we experience a lot of change at once, and why it seems like almost no time has passed when we experience little change.
Because our minds function at different levels at different times (when we are sleepy, drugged, aging, etc.) we can't use our minds as measuring sticks of other change. This is why we use consistent, repetitive change as measuring sticks, like the rotation of the Earth.
The concept of boundary only makes sense in a continuum. It makes no sense for elements of a discrete set. If time is discrete there is no continuum, so the concept of boundary is meaningless.
If you find this notion difficult, consider another type of discrete thing like minds. What could be meant by the boundary between my mind and your mind?
Perhaps change is the marker for dimension. Or is it position that changes?
Not only does it make sense, but it is absolutely necessary. What makes the members of a discrete set discrete is the fact that they are isolated from one another. The thing which isolates one from the other is what I called a boundary. If Y and Z are discrete units of time there must be something real in between them, which isolates one from the other, a boundary. If time is discrete, then what would isolate one discrete unit of time from another? We would have to posit a non-time, between each moment of time. But that doesn't make sense because the only thing which could fulfill this condition of "non-time" would be a stoppage of physical activity. But a stoppage requires necessarily, a period of time with no activity. So we end up with the same description, a period of time with no physical activity.
Quoting andrewk
That's a good example. The boundary between my mind and your mind, is the external world. Boundaries are very real in the spatial world. Though we don't seem to understand them well they are what we sense, so we must hand them some reality if we want to give any credence to empirical knowledge. In the case of time though, we arbitrarily posit points as boundaries. The designated "point in time" separates one unit of time from the next. But there is nothing sensed or otherwise indicating any separation, or differentiation, between one moment and the next. If you believe that time might be discrete, what do you think could possibly separate one moment of time from the next? What gives you any inkling of justification for this proposal?
If mind is what brain does, changing you mind is a change in space and time.
If Mind is distinct from brain, then not so.
Not sure what to make of it. As thought experiments go it's interesting enough.
If we were to entertain reified abstracts (à la Platonism), then inert, timeless entities exist, along with our temporal, changing world. (Not really my cup of tea, admittedly.)
Could something changeless coexist with something that changes? A free photon?
Well, if all change ceased entirely, and somehow resumed, then what would the difference be, from not having ceased? Doesn't seem like a difference to me.
Either way, with micro-chaos, the universe can't be quiet.
That's related to duration. Simultaneity is also of relevance.
I thought we both agreed that you can experience change without experiencing time. Change is change. Time is a measurement of change. You can experience change, but how much time has passed? As I said, you can get lost in your thoughts. Your thoughts change from one moment to another but you don't know how much time has passed until you look at the clock to measure how much time you have been lost in your thoughts.
This is not a good description of time. Even the thing which is used as a measure, must itself be capable of being measured, or else the measurement made by that thing is arbitrary and meaningless. As Aristotle indicated, in one way, time is what measures, and in another way time is what is measured. Therefore your conclusion that just because one is not using time to measure something then one is not experiencing time, is not a valid conclusion because you neglect the fact that one could be experiencing time without measuring it. The fact that something like time can be measured does not necessitate the conclusion that it must be measured in order to be experienced. Measurement is just a special type of experience.
I think where I disagree is with your definition of time. Time can exist without any measurement, that is, we can imagine a universe in which there is no intelligent life; and as such, we know that there would be no measuring of time, and yet time would still exist, and as the primary property of time, change would also exist. Moreover, for us to be able to measure change, change would have to exist prior to the measuring. Change doesn't co-exist with the measurement, that is, you wouldn't say that you have no change until you measure it - of course not, we observe the change, and then we produce an arbitrary form of measurement to account for change within our everyday lives.
Two events separated by space, but occurring a the same time. Is that different to two events separated by time, but occurring in the same place?
Playing the game using the grammar of physics seems to me the best approach. In which case simultaneity is incidental.
Yes, I think it's quite obvious that there is a big difference between these two. Prior/posterior is very different from here/there, because the concept of causation is dependent on the former.
• where: left ? right, up ? down, forward ? backward (indexical "here")
• when: past ? present ? future (indexical "now" = present)
• same when, different wheres: simultaneity
• same where, different whens: place
• same when, same where: identity (indexical "here-now")
• different when, different where: motion or non-identity
It's common, everyday stuff:
• it takes time to get to work in the morning (duration)
• work is elsewhere (distance)
• we get to work about the same time in the morning (simultaneity) as agreed prior (past)
• we have meetings at work (place)
Figuring out simultaneity, for example, is a matter of applying the Lorentz transformation (or more complex varieties, depending on acceleration/gravity and such). Figuring out duration, so that we can largely agree at least, is a matter of stable quantification across applications, to which physicists have come up with caesium fountain atomic clocks (so far).
Duration and simultaneity together seems to suggest dimensionality of some sort, which goes well with relativity and other contemporary science. Does that suggest a (growing) block universe?
(Y)
"Truth functional equivalent". What does that mean? I happen to know that equivalent and the same are not the same thing. 2+2 is equivalent to 4, but not the same as four. So if you claim that a spatial separation is equivalent to a temporal separation, "equivalent" does not mean that there is no difference between them.
I found an interesting video here http://highexistence.com/this-will-mindfuck-you-simultaneity-is-relative/
I don't know McTaggart's argument, but I believe that time is real. I base this on the knowledge that there is a real difference between future and past.
However, after applying the Lorentz transformation, they both agree on that (their different observations).
Check Relativity of simultaneity » Einstein's train thought experiment (Wikipedia article).
By physics, simultaneity is meaningful for reference frames, not universal as such, and the Lorentz transformation tells us how it differs among reference frames.
Exactitude is a different problem.
Might be worth noting that retro-causation remains impossible according to relativity:
[quote=https://en.wikipedia.org/wiki/Relativity_of_simultaneity#Explanation]if the two events could be causally connected (i.e. the time between event A and event B is greater than the distance between them divided by the speed of light), the order is preserved (i.e., "event A precedes event B") in all frames of reference[/quote]
I'm thinking it just means that our language can be confusing. We're not accustomed to tense-less chat. So, the block universe = what was, what is, and what may yet come to be.
Quoting Banno
You will also have to ignore the tensed nature of the A-series, so no you cant just index an A-series.
How about the Block = what was, what is, and what will be?
There is no "may" in the Block.
I am not sure what you mean by "tenseless chat". Under the block universe, every time "is" real. What does the "is" mean here? Does it mean that it was or will be, that they ceased to exist or will come to exist? Certainly not, since that means they don't exist. Or perhaps it means just what we normally mean by the term, that they all currently exist in the present tense.
Quoting jorndoe
I think a better way to say it is that the block universe = Every event in the universe's history. This would include things like the Big Bang, the earth at 2017, and the Martian Outposts in 2100. We speak purely in terms of the particular contents instead of using confusing descriptions like "the things that were" or "what will be", which have a particular meaning to them. To me, under the block universe, every one of these events just "is" in the present tense. The events that we normally take to have existed or will exist actually currently exist somewhere in our universe, though of course not in the same 3D timeslice as our own.
I think the lesson from relativity is that time as a dimension functions a lot like space. That is not to say that time is exactly like space, but that time as a dimension designates locations just like space does. Napoleon didn't cease to exist, he just exists "over there" somewhere in the block universe the same way I say that the planet Pluto exists "over there" somewhere in space.
We now know that time is relative. More accurately, change is relative. Time is what we call the measurement of change. Asking things like, "How much time has passed?" is asking for a measurement of change. You're basically asking "How much did the position of the clocks' hands change during the change I experienced?"
No, change can exist without measurement. Time is simply another change. Measurements are comparisons of the same type of thing. We measure length by comparing it to the length of a ruler. We measure change by comparing it to the change of another system. Yes, time is arbitrary. Change isn't. That is the difference.
The unit of time may be arbitrary, but the EM frequency that excites caesium atoms isn't.
The idea that Einstein provides a "better" explanation of time is what is laughable. You define "better" in relation to what, more useful, or more truthful?
Quoting Harry Hindu
Of course we measure time. Do the words "hour", "day", "year", have no meaning to you? These refer to units of time. You can validate that unit of time by referring to a physical change, but this does not mean that the words refer to the physical change rather than the unit of time. And, in referring to those physical changes, you will see that each of those units of time is measured by those physical changes.
We measure change with time, yes, but as a said, any measuring tool must be itself measurable or else it is meaningless. So if we take time, and use it to measure change, as you suggest, we must also be able to measure time or else "time" is just a meaningless word. Then all of our measurements of change, since they are measured with time, are also meaningless.
Sure they mean something to me, just as inches, meters and light-years mean something to me. They are units of measurement. Hours, days, and years are all units of measurement, too, not units of time.
An hour is the change of position of the small hand of clock. Days and years are changes in the position of the Earth.
Quoting Metaphysician Undercover
Sure, we can measure a meter by using inches and measure light-years by using kilometers. Again, all we are doing is comparing things of the same type (length, distance, or change). Measuring time is comparing different changes. You never measure time. You measure change.
OK then, what does a metre, or an inch, mean to you if it is not the length of some thing? And what does an hour mean to you if it's not the length of some thing?
Quoting Harry Hindu
But we do not measure using inches, we measure using a measuring instrument with one inch increments marked on it.
Quoting Harry Hindu
That's not true at all. For example, the rotation of the earth is my measuring stick, it provides me with one day increments. I count the rotations, one, two, three, four, five, and conclude that five days have passed. I have measured time, five days. I am not comparing different changes. I am observing one particular change which I assume to be constant, and I am using that change to measure time. To verify or falsify my assumption that the change is constant I may compare it to other changes. This validates the accuracy of my measurement, but it has nothing to do with the question of whether or not I am measuring time, it relates to whether or not my measurements are accurate.
Not Einstein, the evidence. Relativity is the most accurate description to date within this domain.
How so? How is relativity a description? What does it describe, and why do you claim that it is the most accurate description of that thing?
Relativity certainly isn't controversial, but it is problematic. To be a bit more precise, Relativity and Quantum Mechanics render each other problematic.
I know the special theory of relativity quite well. Your claim is that "relativity is the most accurate description to date within this domain". Which domain is that? If you think that it is the most accurate description in the domain of time, then I think that this is quite clearly a false statement. Within the domain of time, we describe things as past, present, and future. The present is understood as the point of division between the past and the future. Special relativity asserts that there is ambiguity with respect to this division between past and future. Any description which introduces ambiguity to a point which was previously clear, cannot be considered to be more accurate. Therefore relativity is not the most accurate description in this domain.
So, if you or @Metaphysician Undercover think there is something captured by the A-series but not by the B-series, set it out; but if all you have to say is "you lose the tense", then you have nothing to say.
How can you ask such questions? Again, it seems you do not understand physics.
Perhaps you have not followed McTaggart's argument? The A-series claims there are objective, changing properties of events: they go from future, become present, and then drift into the past. In the A-series, true statements about the future, may become false statements.
I don't general discuss time in these terms, A-series, and B-series. I think "series" already implies an unjustified assumption, as we seem to experience time as continuous, not as a series. I find that past present and future are much more useful descriptive terms when discussing time.
Quoting Banno
A description implies that there is something real which is being described. Jorndoe stated that relativity provided the most accurate description in "this domain". I understand that most physicists do not believe that time is something real, so I was asking jorndoe what is the thing, "in this domain" which is being described by relativity.
Do you? How odd.
Do I really have to cut and paste from the many articles that explain the difference between A-series and B-series?
The A-series is tensed and ordered. The B-series is un-tensed and ordered. The C-series is un-tensed and unordered.
Do you even know what McTaggart was arguing towards?
Oh, yes.
Give me an example of an A-series, true statements about the future, that becomes false.
Yes, I've read that in quite a number of different places. I thought it was odd too when I first came across this. Why do you think that it is odd?
Give me a statement that demonstrates you know what McTaggart was arguing towards.
[quote=https://plato.stanford.edu/entries/time/#McTArg](An odd but seldom noticed consequence of McTaggart's characterization of the A series and the B series is that, on that characterization, the A series is identical to the B series. For the items that make up the B series (namely, moments of time) are the same items that make up the A series, and the order of the items in the B series is the same as the order of the items in the A series; but there is nothing more to a series than some specific items in a particular order.)[/quote]
OK, so back to my questions then. What is it within the macro-domain, which relativity is supposed to provide the most accurate description of?
Quoting jorndoe
Um, the whole point of A-Theory vs B-Theory is that the series are the same. "Odd but seldom noticed"? I don't think so.
Here’s how the conversation should have gone: you say “the cat was on the mat yesterday”. I say that is exactly the same as “the cat was on the mat on sunday 26th”. Then you explain why they are different.
The (macro) evidence is what relativity describes most accurately to date. Samples:
Tests of general relativity » Perihelion precession of Mercury
Gravitational lens
Global Positioning System » History
Error analysis for the Global Positioning System » Relativity
Quoting Metaphysician Undercover
Here's more, has references: Theory of relativity
Quoting jorndoe
(If possible, I'd prefer this thread not to go full metal anti-science.)
Check: Twin paradox
Time dilation has been verified, and is in use.
It is difficult for me to understand this paradox but as you say it is verified with tests.
This and this are almost entirely maths free descriptions of special relativity's use of the speed of light as 'cosmic speed limit' and how it has a consequence of time dilation. This is a series of videos that culminate in a calculation of 'what speed do the photons in a torchlight on a moving cart travel at?' intended for entirely lay audiences.
Quoting MyttenarWho is wrong? The guy who labelled as a paradox the twin-experiment? It is indeed not a paradox. But you're also labelling it a perceptual problem, so again, who's perceptual problem?
Quoting MyttenarOK, you think one of the twins has a perceptual problem. Not so. He sees his clock ticking at normal pace, and he's right. If you assert that he is wrong about this, then please don't explain this stuff to vesko.
Quoting veskoThere isn't one. Everybody is correct about their ages and the durations of their experience. The only problem is the presumption of absolute time, which is something no instrument can measure, and hence has no evidence of existence.
As for A and B series being the same, yes, but both work for a place, even one that moves around. For any place (say where this ping-pong ball is), events are ordered the same way for both series. There is no difference. For two locations (say here and planet Zog), events are ambiguously ordered, both in A and B series. Either way, there is no difference between the series. Neither is an assertion of a metaphysical stance and hence neither is right or wrong. It's just two different ways of referencing the same things.
To say there is no absolute time is to say there is no detectable actual time of the universe. It is meaningless to say exactly when some supernova occurred in Andromeda galaxy for instance. An arbitrary frame of reference must be presumed to do that. Pretty much any statement without a specified reference frame presumes absolute time and/or space. Absolute time would imply that all events anywhere are objectively ordered and that there is a correct frame, but again, no way to determine that frame if light speed is the same in all frames.
Light speed being the same in all frames is the only empirical evidence that led to relativity. Myttenar's picture of things (somebody is wrong) can be falsified by lightspeed measurements.
Read a good tutorial on relativity, especially some of the initial thought experiments that led to the SR parts, and not just the articles that teach the conclusions. The thinking behind it helps so much, and helps one to drop the ingrained presumption of absolute time.
With the twins, the travelling twin's time is dilated in the Earth frame, but in the space ship frames, it is the Earth twin whose time is dilated and exhibits less duration.
The video series I linked titled 'Gamma' from Sixty Symbols on Youtube has a worked example on how to deal with the relativity of simultaneity
Because there's other interpretations, such as a doppler frequency shift due to velocity between us, which looks a bit odd in the face of light-speed is always the same in every frame of reference. Particularly when those measurements suggest a speed of closure or departure between them and us greater than c.
And it also looks peculiar when placed in the immediate vicinity of the Expanding Universe theory, where distance is said to change. Sorta makes one wonder what exactly is meant by velocity = distance/time
Doppler shift, yes. Light is the same speed in any frame. It is not the same frequency or wavelength. Those are frame dependent measurements.
A photon has no objective wavelength or frequency, but a full spectrum beam of light bears the fingerprint of the frame of the source of the light. Hence the speed of some distant star can be assessed by the measurable shift of the light frequency.
If I understand correctly, the activity which results from the expanding universe does not qualify as "motion". So the "distance" between objects may be increasing, but this is not properly called a motion.
If distance loses it's meaning of 1 lightyear = 1 lightyear the fraction distance/time becomes meaningless as well.
Does that look like science or fiction?
Speed and velocity are not absolute properties of objects. They are relations between things.
It is still distance, but Meta's post above is correct. Distance is a local measurement that begins to alter meaning for significantly separated things.
Which, together with the mentioned empirical perspective (no change implies no time), intrinsically relates time and change.
Was it Aristotle that noted they're not the same thing, though?
Change and motion and such could be many things, whereas time is more specific (e.g. concurrent duration).
Change takes time, that is self-evident, but why does no change imply no time? Don't you think that it is possible that time could be passing while things are staying the same?
In other words if there is no change/movement in universe ,than there will be no time category.
Human beings make categories. Without a human being there is no time category. I'm asking if you think that there could be time without change. Or is the time category just an empty category?
certainly ,no change means no time ,. And also no humans means that nobody can realise the time ,including we in this forum ?
Why do you say "certainly, no change means no time". Humans realize time through change. The principle used is simple, If change occurs, then there is time. How can you invert this to say "if there is time, then there is change", to make your statement with certainty?
In other words, we know that time is necessary for change, because we abstract time from change. Therefore we know all instances of change involve time or else this abstraction would be invalid. But we do not ever proceed from the observance of time, to conclude that change has occurred. We cannot make this abstraction. Therefore we cannot know with any certainty that all instances of time involve change.
You have committed a fallacy of false equivalence, thinking that because all change involves time therefore all time involves change, as if time and change are equivalent.
Yes I do. and time itself is a change