Relative Time... again
Relative time: how do you understand it? Defining it negatively, it means time is not something objects pass through. Time is a dimension. It's an aspect of an object.
This came to me again today while I was listening to a Cure cover of a Jimi Hendrix song. It took me back to my childhood when the door to the future seemed like the gate on oblivion. There was a lot of pessimism about there being any future for the human race.
But what is the future exactly? If in some sense it already exists (Brian Greene said), then are we not all facing oblivion at this moment? Because that future you is not the present you. Or maybe you will be there in the future as something implied (as the outer shell of the nautilus implies the inner chambers.)
This came to me again today while I was listening to a Cure cover of a Jimi Hendrix song. It took me back to my childhood when the door to the future seemed like the gate on oblivion. There was a lot of pessimism about there being any future for the human race.
But what is the future exactly? If in some sense it already exists (Brian Greene said), then are we not all facing oblivion at this moment? Because that future you is not the present you. Or maybe you will be there in the future as something implied (as the outer shell of the nautilus implies the inner chambers.)
Comments (57)
Scientifically speaking, time is that which a chronometer measures. There is such and such a tension placed upon a visual apparatus with a slightly lesser tension, and the first tension changes the apparatus at what appears to us to be regular intervals.
I do not understand time at all, except in common parlance. I know that I must clock in 2 days from now 5 minutes prior to 7 am (central standard). But to define what seems to be something wider and more general in terms of my life now doesn't seem quite right.
I rather like Heidegger's take when he says that we are time. But, at the same time, I am not certain what it means. It just strikes me "right", in comparison to the alternatives.
Time is either going to be a global dimension through which things move or it is instead a measure of local change. And as usual when faced with a compelling dichotomy, the answer is going to be you need to combine both to get a full answer.
So time is clearly about a local potential for change - what could happen in the future of some object or substance in terms of its degrees of freedom. How could what is currently the same become something different.
And time is just as clearly about a global constraint on all that. Time has a universal direction in which the past represents an accumulation of all the ways the present has become historically limited. And that leaves then the localised degrees of freedoms - the possible future of all those existing objects or substances.
So time measures change against some notion of stasis. It measures the differences that make a difference. When we say an object moves through time, we mean that it doesn't change while the history all around it is changing - eliminating degrees of freedom in many other locations. And then there comes the moment where the object does itself change - becomes further historically marked in some way we consider different enough to make a difference. Now it is the changing object being seen against a static backdrop.
So it is all about flux vs stasis. And we can read that off the world either as local flux seen against generalised stasis, or local stasis against generalised (cooling and expanding, thermal arrow of time) flux. It's all relative, as relativity says.
I don't either. Leibniz's demonstration of the relativity of space is pretty simple. I don't remember if he addressed time with it as well, but this is how it would go:
Leibniz on relativity of space: If time is absolute (therefore a container for objects and present in a void), then God would be able to move the whole universe 50 miles to the west. We can see that even in principle no movement would be observable and by Leibniz's law, no movement took place. Space can't be absolute.
Same argument to address time: If time is absolute (and so something objects pass through and present in a void), then God would be able to turn the universal clock back by 4 hours. We can see that even in principle, no time change would be detectable, so blah blah blah.. no change in time took place. Time can't be absolute.
Criticisms? So.. Kant.
I like their Stone Free cover.
The concept of the object is a the construction that takes place in time,
until its got the rhythm "to ride the breeze" of your imagination,
Stone free, yeah, to do what I[you] please
Similar to a music you can anticipate future beat.
Modern physics changes things by bringing change directly into the picture as action or energy. Nothing has substantial being - neither massive objects nor the massless space they occupy. It is all just shapes given to energy transactions. So it becomes natural - if not formally expressed in that fashion - to measure time in terms of energy units.
The greater the momentum, the slower the local clock runs. The speeding particle gains "more time" because it takes longer to decay. Or conversely, you can say it loses the potential for change and becomes more the changeless object. Like the photon that goes so fast it never really exists so far as it is concerned.
By contrast, a static mass is in a least energetic state and so experiences the actuality of global temporal dimensionality the most fully. It can actually fail to change in knowing itself to remain in the same location while everything else has moved. And then know that is itself moving as mostly everything else is staying the same now.
So the picture of time is completely changed by including energy or action as part of the co-ordinate system. It may still sound a spatialised description - as when we count the revolutions of a clock hand making its exactly repeating round trips (a way to watch something move, but not let it run away out of sight). But the clock has to be wound up. So the spatialised trickery is still the measurement of some energy potential. Which we soon discover when accelerating the clock in a rocket.
Yep, it's Purple Haze (which contains the line: "Tomorrow is the end of time."
Concepts are timeless though, aren't they?
Leibniz argued directly against absolute space (which is associated with Newton). Why do you think he was operating in a Newtonian reference frame?
I don't see how this argument makes sense. If time were absolute then God could turn back the time by 4 hours. But no time change would be detectable to us. So how do we know that God didn't turn the clock back 4 hours, and a change in time which was undetectable to us didn't take place?
I mean do you think his arguments work against the relativistic view and its particular features, like the Einstein hole argument?
They can sound similar, but then they may be quite opposite in fact...
Pure concepts of the understand (timeless) vs empirical concepts (constructed in time) temporal time series ... "Time is a dimension. It's an aspect of an object"
It's not "undetectable to us." It's undetectable even in principle. Then apply Leibniz's Law.
How does Einstein's hole argument relate to relative time?
You're saying that a proposition is constructed in time? You mean one word at a time?
Yes, but the sentence and the thought aren't the same thing. The same thought can be expressed by different sentences.
I'm asking how it relates.
Coursing through the flesh
And flesh itself is magic
Dancing on a clock
And time itself
The magic length of God
Leonard Cohen
No, don't know what time is, or what time it is.
We might say relativity is absolute. God can "turn the clock back," destroy the present states and reorder the world in a way similar to what was four hours ago. But what does this mean? It doesn't undo what has already happened. All it does is wipe out certain states (or viewpoints) in favour of others.
The presence of an objective state means relativity: this state rather than any other, here rather than over there, the present rather than the future, etc. To even think or speak: "the world as four hours ago (past) rather than as it is now (present)" is relativistic in its definition-- viewpoints in relation to each other.
So for instance you were imagining Leibniz running a relativistic argument against Newtonian time by God turning back the universal clock by four hours and seeing no difference.
Well great. Newtonian mechanics is reversible like that. It does have that time symmetry. That is why time seems like a dimension one can freely time travel in.
But once you admit energy into the picture - global time as entropically-directional change - then going back in time is actually going to break a symmetry. If you go back four hours, the whole universe is now four hours hotter ... as well as four hours smaller. There are actual consequences that a thermometer would reveal.
So Einsteinian relativity tries to recover some of the good old Newtonian scale indifference. It gives you a formula for handling "energetic Lorenzian boosts" - the symmetry-breaking effects of going at some other speed less than c.
So on the one hand, we still seem to have backdrop time - and quantum mechanics says thank goodness for that.
But then next up on the batting plate is quantum gravity theory and now we really have to rethink our notion of time so that it does align with a thermal view - uni-directional emergent energetic change.
Talk about time is tricky because really it is about relative rates of change - change overall in a cooling/expanding universe versus change locally due to relative energy scale. And each is the backdrop against which we read off the other - that is the lightspeed view (of a thermalising bath of cosmic background radiation) vs the restmass view (of these lumpy, sluggish particles of "mass" that can "move through time" just by, relatively speaking, not moving at all).
Again, I have no idea whether you have a concrete thesis or any actual interest in the science involved. But a thermometer would tell you if you have wound the Universe's clock backwards (just hold it up in deep space and measure the temperature of the CMB).
But there is no clock, and 4hrs ago is still there, according to science anyway.
So you thought I was conflating Leibniz and Einstein. OK. That wasn't my intention.
Quoting apokrisis
You're thinking that when God turns the universal clock back, that NOW is moved backward. The universe isn't a point in time. It's all of time. So God is moving all of time back four hours. See? You've got to stop thinking of time as a river that things flow through. That is Newtonian time.
Propositions and sentences?
Actually, scientifically speaking, clocks don't measure time.
According to quantum mechanics (and general relativity) the universe as a whole is at rest. That is, that the universe is in an eigenstate of its Hamiltonian - i.e. the Schrödinger equation gives a universal wavefunction that is independent of time. This means that physical quantities do not depend on time.
So, whatever physical quantity is used to tell the time, the universe is not in an eigenstate of that physical quantity - i.e. the universe is not in an eigenstate of the positions of the hands of a clock. Rather, the universe is in a superposition of such states!
Thus, quantities "changing with time" has nothing to do with t-dependence, it is a correlation phenomenon.
Sounds legit.
That would seem to be the same problem afflicting the idea of displacing the whole of space. You can shift a house 100 feet to the North. Can you move the whole of space in the same direction? What would such a hypothetical displacement be relative to?
There is no need for God to wind the clock back, because there is no clock. The state of the universe that correlates with the clock position of 4hrs ago, is still there.
This experiment demonstrates what god sees:
https://medium.com/the-physics-arxiv-blog/quantum-experiment-shows-how-time-emerges-from-entanglement-d5d3dc850933
If God moves time back, then God knows that time is moved back. If God knows this, then it is in principle "detectable". We need to allow for the possibility of things which are undetectable to us, but are detectable by means which are not available to us. This would not negate the absoluteness of time, because we allow for absolutes within different categories, just like different infinities. So time would be absolute, but not the absolute absolute because we've allowed God into this scenario, and God takes that place.
Right. Leibniz shows the problem of absolute space by imagining the universe is finite and sitting in a void. Assuming absolute space, the void is empty space waiting to contain something. We might imagine xyz axes expanding out from the center of the universe and continuing on beyond it.
It's only when we imagine the universe moving within the void that the logic of it breaks down. We have proposed motion that even in principle can't be observed.
Einstein also takes us to a void in special relativity. Again, we're looking at the meaninglessness of trying to travel around in a void.
Trying to adapt the thought experiment to address time is a little confusing to me.
Which is not what the universe is like. It's infinite.
Can't you ask essentially the same question about time? Anything that occurs (e.g. the construction of a house) could have occurred four years earlier (or later). But could everything that is occurring (and occurred, and will occur) in the whole universe occur four years earlier? Relative to what event would everything have occurred four years earlier?
The entropy of the visible universe for example.
Well, I was assuming all the micro-physical "events" to be shifted as well, not just the macroscopic ones. Since the entropy of a physical system supervenes on its micro-physical state, then the entropy of all the systems (including local cosmic background radiation) would be shifted back in time by the same amount.
The change is relative to God. That's the issue, the proposition assumes a God to carry out this act, so we cannot just dismiss God now, to claim that the change is not relative to anything. Now God is understood as an immaterial being, so the change is relative to an immaterial existence. The change is undetectable to us, because we gauge time by judging material changes, but now we've assumed an immaterial existence, and this immaterial existence must have some other means of gauging time.
The possibility that time and space are limitless is confusing me. But is that a problem? Can the thought experiment just say that for every E, E happens 4 hours earlier? And not address whether time is finite or infinite?
It's a reductio ad absurdum argument. God's decision to move the universe is not a premise, it's the object of analysis. Does it make sense for God to move the universe?
Could be.
The same question arises. Relative to what is everything happening four hours earlier? You have to imagine some undetectable framework of time (rather in the way one might want to picture empty space, metaphorically, as an empty stage) relative to which events are dated extrinsically. But if that's the case, then there would have occurred a shift in the time of occurrence of all the empirical events, all right. But time itself would not have shifted since it would have been externalized, as it were, to this inobservable framework.
Let us get back to the space analogy. We could imagine "space itself" being externalized in a manner somewhat analogous to the luminiferous aether of pre-relativistic physics; with the proviso that such an aether would be physically undetectable in principle. Can then everything in the universe be conceivably shifted 100 feet in one determinate direction? This can be conceived. But you still would not have shifted space itself, since on that account, space would have been externalized. It has been identified with the absolute spatial "positions" of the aether "stage". And this aether still would not have moved. If you were to imagine that the aether (space itself) also moved, then that must be a movement relative to some external spatial framework. You need another aether to identify "space itself" with. You are led to an infinite regress.
If you believe in God, yes. If you do not, no. God is an immaterial existence, so if time is relative to God, then a change in time does not necessitate a change in material existence. But if you do not believe in God, then there cannot be a change in time without a change in material existence.
You asked what time could be reversed relative to. Total entropy is one measure.
Anyway, not even God cand wind back something that doesn't exist. All she needs to do to observe the state of the universe that correlates with my clock 4hrs ago, is index the space-time.
Maybe someone else, not me. I didn't touch on the issue of the arrow of time. I was only considering the intelligibility of the idea of shifting the temporal scale (or all events) four hours in the past (or in the future), in analogy with the idea of a uniform translation of space itself.
If it's a "scale" it just needs renaming.
That would be the word of God? Could we trust God's word, that it really happened?
You use a clock.
Yes, if what is being denied under the label "relative time" is the intelligibility of the idea of an absolute positioning of events in time, then the argument against the idea of an absolute positioning of events in space works just the same for time, it seems to me.
I don't know; I'm not familiar enough with Leibniz's metaphysics.
I wouldn't go as far as saying that picking a point in time is actually picking an event. (I assume you mean "event" to refer to something more substantive than what physicists call events: i.e. mere space-time points). But it does require there being a substantive framework (e.g. an actual set or rulers and clocks) relative to which temporal (as well as spatial) locations are defined.
If you put a clock in a void, you will have injected time into it. True?