Defining Time: Our Everyday Mystery

[Pilot7]

Indeed time has to do with change but then what is change? An object as long as it isn't in the absolute zero will always have thermal motion so internally it continously changes. But change is always thermal motion or motion in general?of course not for example when a particle and an antiparticle anihhilate, mass is converted(changed) to energy (although this process still involves motion of the particles). I guess the notion of change is elementary and cannot further be explained.

Indeed - but is change elementary? Currently not in any physical theory I know of.

One of the difficulties in talking about 'change' is that we currently lack a specific or concrete way of talking about it. THis was the direction of my own work: develop a logic that makes 'change' explicit.

If you think through this a bit and take a look around, you will find that (almost) all attempts to such reduce the notion of change to a relative frame of reference involving 'time' -- ahhh, but what was time? I thought we had defined 'time' in terms of 'change'!

Round and round we go...

However, if you try to define 'change' without reference to time, you find you get into theoretical deep water very quickly. The problem is to develop a *consistent* logic that does this, and it may indeed be impossible.

If there is a way to formulate a consistent logic to speak of change, it is going to require a radical rethink of the way we identify reality: one has to move to a system of perspectival moments instead of socially acknowledged absolute events (which are the foundation of the physical and scientific enterprise -- we need all to be able to refer to specific experiments and agree on the outcome...)

Another alternative is the development of what are called 'para-consistent' logics: Here you provide for limited inconsistency in the theoretical expressions referring to the phenomenological world.

If this is sounding like Greek, let me put it this way:

You want to find a way to speak about say a glass of wine on a table in one moment and the *same* glass of wine on the floor in another moment, and you want to find a way of speaking about this 'change' without referencing 'time'. If you say the *same* glass of wine is both on the floor AND on the table, there is an intrinsic inconsistency.

Most logics (including the 'languages' we call physics and mathematics) are not formulated in a way to allow even a single inconsistency.

This seems to be the rub of the problem on the theoretical side.

 

[K^2]

There are three entirely different and only somewhat related things that are meant by people when they say "time".

1) Time is a parameter in Quantum Mechanics. It has absolutely none of the typical connotations. It's an arbitrary quantity by which the system's state is parametrized. An infinitesimal change in time-parameter results in infinitesimal change in state. A differential equation relating two infinitesimal changes can be found.

2) Time is a dimension in General Relativity. Very straight forward. It's just a distance in a fairly arbitrary direction in 4-space. There are restrictions on which direction you can pick, but there are still infinitely many possibilities. Two coordinate systems with different choices of time direction are moving relative to each other.

There is a relationship between time in Quantum Mechanics and time in General Relativity, in that if you measure change in GR time along particle's own world-line (Proper Time), it agrees with change in time-parameter in particle's equation of state. This has many useful consequences. For example, it let's us build clocks.

3) Time is the ordering of states in Statistical Mechanics. This one is probably the most interesting one. It's the one that tells you why you remember yesterday, but cannot remember tomorrow, even though in both QM and GR the two directions in time are absolutely identical. Entropy of a closed system cannot decrease. Second Law of Thermodynamics. Another way to read this law is that the state with higher entropy must come after the state with lower entropy. This is very important, because process of storing information requires an increase of entropy in the surrounding. That means that information is always available only about events on one side of time axis from moment in question. That's what let's you recall yourself recalling something else, and gives the entire effect of time flow.

 

[Pilot7]

There are three entirely different and only somewhat related things that are meant by people when they say "time".

1) Time is a parameter in Quantum Mechanics. It has absolutely none of the typical connotations. It's an arbitrary quantity by which the system's state is parametrized. An infinitesimal change in time-parameter results in infinitesimal change in state. A differential equation relating two infinitesimal changes can be found.

2) Time is a dimension in General Relativity. Very straight forward. It's just a distance in a fairly arbitrary direction in 4-space. There are restrictions on which direction you can pick, but there are still infinitely many possibilities. Two coordinate systems with different choices of time direction are moving relative to each other.

There is a relationship between time in Quantum Mechanics and time in General Relativity, in that if you measure change in GR time along particle's own world-line (Proper Time), it agrees with change in time-parameter in particle's equation of state. This has many useful consequences. For example, it let's us build clocks.

3) Time is the ordering of states in Statistical Mechanics. This one is probably the most interesting one. It's the one that tells you why you remember yesterday, but cannot remember tomorrow, even though in both QM and GR the two directions in time are absolutely identical. Entropy of a closed system cannot decrease. Second Law of Thermodynamics. Another way to read this law is that the state with higher entropy must come after the state with lower entropy. This is very important, because process of storing information requires an increase of entropy in the surrounding. That means that information is always available only about events on one side of time axis from moment in question. That's what let's you recall yourself recalling something else, and gives the entire effect of time flow.

Yes in the rought. However there is more to be said and a few minor corrections and a major conceptual issue to addres and one paradox in a pear tree...

QM - there is an asymmetry in one case: some kind of muon (I forget which - kaon? Pion?)

However, yes, it is a theoretical parameter with complex value. However, even how this parameter is computed specifically varies in certain contexts (this is what I meant earlier about the.. seven times of quantum theory - btw, there was a nice book a few years ago with a title along those lines - can look it up if you are interested)

GR time is fairly straightforward (bad pun!) provided you stick to classical worldlines only. And no revolving universes (Goedel universes). If you allow the latter, you get backwards time travel, which is not necessarily a problem in itself... unless you think there is something to freewill. In which case you just got in hot water for a number of reasons.

There is also a minor issue that has been proposed in the so called hole argument, but I don't think it amounts to anything personally (sure, let that one be a pun intended).

If however you mix up QT and GR you have issues per the EPR paradox for example. This is very troubling if you are the sort of physical thinker who likes to create problems. A lot of fundamental ontological questions get asked, including the fundamental nature of time (as some kind of parameter on some kind of states, whether QT or classical).

As for CP (Classical Physics) and entropy (whatever that is exactly) - I was never satisfied by the definition of time based on this. There are several reasons why, but to highlight a few points:

Remember, the 2nd law of thermodynamics speaks in terms of time in the first place. However, if you grant that, it is sometimes interpreted as explaining directionality, and this is really a big mistake. At best you get asymmetry, not directionality, which is a more subtle concept that invokes intentionality (philosopher's term - but basically the idea of meaning or semantics). It is worth adding that even the asymmetry aspect breaks down in certain borderline cases as I believe Penrose demonstrated.

Anyhow, it is a very big jump to suppose that the 2nd law of entropy is responsible for inability to remember the future and only the past. To say this has not be proven or demonstrated in any sense by anyone is no far fetched claim. That is just one of the dogmas of the religion of scientism (ie it is not at all science...)

Cheers!
Pilot

 

[Pilot7]

right, and forgot to add most importantly...

In QT, there is a big difference that arguably results from treating wave collapse as ontological. If you do that, then it begs a time frame for successive quantum states. That is not the only way of course to treat quantum events. Note my reference previously to the EPR paradox in this respect.

K - going to step away from this can of worms now and do some work.

 

[Delta2]

However, if you try to define 'change' without reference to time, you find you get into theoretical deep water very quickly. The problem is to develop a *consistent* logic that does this, and it may indeed be impossible.

If there is a way to formulate a consistent logic to speak of change, it is going to require a radical rethink of the way we identify reality: one has to move to a system of perspectival moments instead of socially acknowledged absolute events (which are the foundation of the physical and scientific enterprise -- we need all to be able to refer to specific experiments and agree on the outcome...)

Another alternative is the development of what are called 'para-consistent' logics: Here you provide for limited inconsistency in the theoretical expressions referring to the phenomenological world.

If this is sounding like Greek, let me put it this way:

You want to find a way to speak about say a glass of wine on a table in one moment and the *same* glass of wine on the floor in another moment, and you want to find a way of speaking about this 'change' without referencing 'time'. If you say the *same* glass of wine is both on the floor AND on the table, there is an intrinsic inconsistency.

Most logics (including the 'languages' we call physics and mathematics) are not formulated in a way to allow even a single inconsistency.

This seems to be the rub of the problem on the theoretical side.

First all i am greek myself ) some of it sounded not greek but chinese i would say (hehe both greek and chinese are civilizations with big history anyway). I still don't see it as a problem of consistency/inconsistency/partial or limited inconsistency, rather i see it as a problem to express something which seems to be elementary in other more trully elementary concepts.

There are three entirely different and only somewhat related things that are meant by people when they say "time".

1) Time is a parameter in Quantum Mechanics. It has absolutely none of the typical connotations. It's an arbitrary quantity by which the system's state is parametrized. An infinitesimal change in time-parameter results in infinitesimal change in state. A differential equation relating two infinitesimal changes can be found.

2) Time is a dimension in General Relativity. Very straight forward. It's just a distance in a fairly arbitrary direction in 4-space. There are restrictions on which direction you can pick, but there are still infinitely many possibilities. Two coordinate systems with different choices of time direction are moving relative to each other.

There is a relationship between time in Quantum Mechanics and time in General Relativity, in that if you measure change in GR time along particle's own world-line (Proper Time), it agrees with change in time-parameter in particle's equation of state. This has many useful consequences. For example, it let's us build clocks.

3) Time is the ordering of states in Statistical Mechanics. This one is probably the most interesting one. It's the one that tells you why you remember yesterday, but cannot remember tomorrow, even though in both QM and GR the two directions in time are absolutely identical. Entropy of a closed system cannot decrease. Second Law of Thermodynamics. Another way to read this law is that the state with higher entropy must come after the state with lower entropy. This is very important, because process of storing information requires an increase of entropy in the surrounding. That means that information is always available only about events on one side of time axis from moment in question. That's what let's you recall yourself recalling something else, and gives the entire effect of time flow.

1 and 2 are very mathematical ways of looking at time, it might be convenient to look it that way for QM or GR . However how can we say that the two directions in time ( i suppose u mean backward and forward) are identical since entropy increases as time increases and if we could go backwards in time we could have a decrease in total entropy.

 

[Pilot7]

First all i am greek myself ) some of it sounded not greek but chinese i would say (hehe both greek and chinese are civilizations with big history anyway). I still don't see it as a problem of consistency/inconsistency/partial or limited inconsistency, rather i see it as a problem to express something which seems to be elementary in other more trully elementary concepts.

1 and 2 are very mathematical ways of looking at time, it might be convenient to look it that way for QM or GR . However how can we say that the two directions in time ( i suppose u mean backward and forward) are identical since entropy increases as time increases and if we could go backwards in time we could have a decrease in total entropy.

Well Yahsu! Or Nee Hao Ma!

Yes, so we have an apparent elementary quality and maybe there is something more elementary we can use to define/characterize/address it. Maybe.

Here was my approach: First, tease out all the features that bundled together with what we mean by time. There are quite a few... for example,

1. There are several structural layers. It is one dimensional or two (noting complex case in QT). It has a metric, a topology, etc. etc. Ultimately, all of these structural features boil down to a set theoretic expression defining:

i. a set
ii. with a topology
iii. with a metric
iv. asymmetrical structure

and so on. Doing this actually helps to clarify the rather significant differences evident in different physcial characterizations of time. Okay, this was the 'easy' part of the problem. Now to the hard part...

i. it has direction
ii. it has 'flow'
iii. it has a magical locus called a 'now'

There are two ways to go. Either we say all this other stuff is 'psychological' and leave it to the psychologists to sort out (personally, not an approach I recommend!) or we rethink what we mean by physical properties.

If we go the second way, it may well be that there are more 'fundamental' ways to speak about time - in fact, that is my own personal 'religious' intuition on the issue - but whatever the 'truth' of the matter may be, we need to find a way to even speak about it.

In this sense, we need to be able to speak about something like 'change' or 'now' or 'direction' or 'flow' (as a 'quale' or phenomenological qualityity) in terms that a hard nosed physicist can actually smell it so to speak. That is not easy in some cases.

Sure, we can define 'now' as a perspective - that is relatively unproblematic. But direction has no meaning in the physical lingo nor does flow or change...

So without this, how can we ever hope to find the real elementary parts upon which what we called time is built/structured/made? For even if we epiphony our way to an answer, we still do not have the language or semantic tools to speak about these things...

 

[K^2]

1 and 2 are very mathematical ways of looking at time, it might be convenient to look it that way for QM or GR . However how can we say that the two directions in time ( i suppose u mean backward and forward) are identical since entropy increases as time increases and if we could go backwards in time we could have a decrease in total entropy.

Yeah, the directions themselves are symmetrical, so it must be something about the states in the two direction that result in the "arrow of time".

If you allow me a bit of speculation here, because there are a few shaky points in what follows, I can try to suggest a solution. If we take GR as our starting point for looking at the universe, the entire universe as a whole just is. It's not really expanding, or evolving, or doing anything else. It's a 4-manifold with some fields in it. For whatever reason, it happens to be "larger" on one "end" of what we call time than the other. Specifics aren't important. What's important is that if our notion of entropy as applied to a closed volume still applies to the entire space, we must conclude that the total equilibrium entropy is higher where the time-section of the universe is larger. This is one of these shaky points, because we are now dealing with stat-mech, which relies on QM, in context of GR, and GR and QM don't agree. We really need Quantum Gravity here. Now, this is equilibrium entropy, and we are dealing with non-equilibrium system. So something else must be going on. It seems like it should work out in Many-Worlds, but again, can't do Many-Worlds and GR at the same time without Quantum Gravity.

Short version - We really need Quantum Gravity to properly describe time, but expansion seems to be responsible for the arrow of time.

Edit: Pilot7, you can't treat time as a purely mathematical entity. It's related to entropy, we know that, so you aren't going to be able to describe time without keeping stat-mech in mind.

 

[Delta2]

Short version - We really need Quantum Gravity to properly describe time, but expansion seems to be responsible for the arrow of time.

Suppose time occasionally goes backward in this universe, if that is happening in the universe as a whole (as expansion is happening on global scale ) how could we ever observe it? Since our brains are living in the universe when time goes backward, it goes backward for our brains too and all of the neurobiochemical processes of our brain which are responsible for the storing of info are reversed too and this is info is just removed from our minds. It is like growing old and then with time reversal becoming baby again but once you become baby all of your memory is removed and you won't remember that you had grown old.

The only way to observe time reversal is if it is happening on confined region of the universe and the observers are out of this confined region.

 

[MJA]

Tic Toc

Historically time was a manmade mathematical tool designed to measure the motion of the stars. Today we use it not only to measure everything including ourselves, we also use it to control ourselves. Unfortunately time is as uncertain as any other of our manmade measures of nature, and Heisenberg's Uncertainty Principle truly only the tip of the berg.
Time is as all of our measures only theoretically quantum mechanical at best.
And beyond our current best measurements is the absolute truth.
God doesn't play dice, but we do.

=

Need proof?
What time do you have?

 

[Pilot7]

Yeah, the directions themselves are symmetrical, so it must be something about the states in the two direction that result in the "arrow of time".

If you allow me a bit of speculation here, because there are a few shaky points in what follows, I can try to suggest a solution. If we take GR as our starting point for looking at the universe, the entire universe as a whole just is. It's not really expanding, or evolving, or doing anything else. It's a 4-manifold with some fields in it. For whatever reason, it happens to be "larger" on one "end" of what we call time than the other. Specifics aren't important. What's important is that if our notion of entropy as applied to a closed volume still applies to the entire space, we must conclude that the total equilibrium entropy is higher where the time-section of the universe is larger. This is one of these shaky points, because we are now dealing with stat-mech, which relies on QM, in context of GR, and GR and QM don't agree. We really need Quantum Gravity here. Now, this is equilibrium entropy, and we are dealing with non-equilibrium system. So something else must be going on. It seems like it should work out in Many-Worlds, but again, can't do Many-Worlds and GR at the same time without Quantum Gravity.

Short version - We really need Quantum Gravity to properly describe time, but expansion seems to be responsible for the arrow of time.

Edit: Pilot7, you can't treat time as a purely mathematical entity. It's related to entropy, we know that, so you aren't going to be able to describe time without keeping stat-mech in mind.

@K^2

I like the model - I think this is roughly the way one has to go in thinking about this if one takes going theories as they currently are.

I should probably clarify some of what I said before not to be misunderstood. I don't think time actually is just a mathematical construct, nor do I think this approach in itself is helpful. What is helpful is separate out its constituent qualities as we try to understand it, and in this sense, we want to in a way isolate all of its mathematical properties on one side so to speak.

Yes, of course entropy is clearly a very important part of whatever is actually going on, and statistical mech (as founded on QT) is a very important part of the equation so to speak. And while I do not think all of 'psychological time' will reduce to SM as is sometimes advocated by a certain subsection of the faithful who pray at the alter of scientism, that doesn't mean it is still not clearly a very important part... In other words, entropy is arguably an essential or necessary aspect of our temporal experience, but it is not a sufficient foundation in itself.

One of the very, very important aspects to keep in mind here is what we mean by the 'arrow of time' which has really created a mess in the literature. Because there are different sorts of qualities that need to be distinguished clearly (asymmetery, anisotropy, direction, etc.) and part of why I try to avoid using the arrow of time metaphor.

Anyhow, following through on your model - so we have a big hyper-dimensional blob that models the universe GT style. And for the most part (except at the edges) it behaves like a good differential manifold (I think I am getting terms right - I'm a bit rusty on some of this). Now we want to identify 'entropy' in our big puzzle board - so we say it is a relative measure of organization of parts of fields in different regions of our blob.

Based on this, can we show or dot in a time dimension that is 'perpendicular' so to speak of the gradient of entropy regions? Or are there many such entropy time lines?

But this approach partly begs the question of what we mean specifically by entropy, which can be treated differently in different contexts. I will admit that I feel like I have tended to play a little fast and loose with entropy here and not done my home work to get very clear about what it means or how to represent it, in the sort of model you have sketched out for example.

Ok - defintely feel like I am rambling now, so will stop...

 

[Pilot7]

Suppose time occasionally goes backward in this universe, if that is happening in the universe as a whole (as expansion is happening on global scale ) how could we ever observe it? Since our brains are living in the universe when time goes backward, it goes backward for our brains too and all of the neurobiochemical processes of our brain which are responsible for the storing of info are reversed too and this is info is just removed from our minds. It is like growing old and then with time reversal becoming baby again but once you become baby all of your memory is removed and you won't remember that you had grown old.

The only way to observe time reversal is if it is happening on confined region of the universe and the observers are out of this confined region.

Careful - you really need to be clear on what 'time going backwards' means... do you mean the universe is infused with an ether of 'causal arrows' of some kind? Do you mean that local conscious experience has rearranged its successive states of awareness and the 'intentionality arrows' between phenomena are reversed? Important to be clear on what going backwards (or forwards) actually means...

 

[Delta2]

Careful - you really need to be clear on what 'time going backwards' means... do you mean the universe is infused with an ether of 'causal arrows' of some kind? Do you mean that local conscious experience has rearranged its successive states of awareness and the 'intentionality arrows' between phenomena are reversed? Important to be clear on what going backwards (or forwards) actually means...

I can't possible know how a time reversal could be initiated and further analyzed but in a time reversal as i see it, the effect becomes the cause and the cause becomes the effect. Everything goes like someone pressed the reverse playback button on a video player. Not sure what will happen to the local conscious experience but i guess if with time going forward we gain experience, with time going backwards we lose experience. So if we indeed lose experience when a time reversal happens we could never realize that it has happened. Perhaps all that remains is a deja vu feeling but then again this means that the time reversal was not ideal.

 

[K^2]

If you COMPLETELY reverse time, nobody would notice anything. You only perceive time because of your ability to remember things, and if your memories run "backwards" along with everything else, you still perceive time in the original "direction".

The more interesting question is what happens in localized time-reversal. There have been experiments where dynamics of a system is locally reversed. That is equivalent to local time reversal. However, there is a problem. There is no way to interact with a time-reversed state without altering it, and if you alter the state, you ruin time-reversal. So while we can run time "backwards" in a small closed system, we cannot use it to send information, and so it's useless for any practical purpose.

 

[Pilot7]

Backwards time 'travel' --

Here is the thing - first before we can talk about 'backwards' time travel, we need to understand 'forward' time travel. And that requires us to be clear by what we mean by 'travel' altogether! And looking more closely at that, we need to understand or define identity, as in 'bob travels' - what do we mean by 'bob'?

So I invite you all to consider very carefully what is identity – as in why is YOU the same YOU that was yesterday/tomorrow? Think of it this way, we are here now. And we have clones in the past and future. And we thing those clones are US – and happily our clones feel similarly, identifying with us through memory and expectation – not unlike the Borg actually...

Can we then transpose this sort of identity onto objects putatively without an inner sense or consciousness of identity? Can we say that electron is a clone of that electron that was fired out of that cathode ray tube?

If we can get clear on what we mean by identity, then we talk about travel. If we can get clear about travel, then we can get clear about interaction and causality. If we can do that, we can begin to speculate about what direction might mean. If we can do that, we can make sense of forward. If we can do that, sorting out backwardness will follow easily...

So on that, your local philosopher friend leaves off with a warning: Beware my physicist friends, pay attention to your fundamental assumptions :-)clone Pilot7-555 signing out

 

[Selraybob]

I've been reading through a bunch of these posts, and I can't get it out of my craw that Time is just a count. There are all of these complicated, mathematical theories that make Time into a fourth dimension or some theoretical math thing, but it's just a count. All we've ever been doing is counting things that happen, counting and marking them on the wall.

 

[Pilot7]

I've been reading through a bunch of these posts, and I can't get it out of my craw that Time is just a count. There are all of these complicated, mathematical theories that make Time into a fourth dimension or some theoretical math thing, but it's just a count. All we've ever been doing is counting things that happen, counting and marking them on the wall.

Suppose we were to analyze the metabolic system of New York's finest and discovered it was all down to counting donuts. Would you be willing to say that it is just counting in that case? Why not? What else is there to donuts besides their number? If there really is nothing besides the count, then presumably we could replace the donut part of the equation with, say, vacuum or hot air, just keeping the number the same...

If there really is nothing to time but count, then we should be able to replace this with anything else that lacks 'substance' -- for example, units of zero dimensional distance or something.

Insofar as the laws of physics bear on reality truly, time is a remarkable mystery...

 

[Selraybob]

PILOT7,
I'm not used to writing on things like this. My friend Herm got me to do it. But you're right about the donuts. All the counting has to be of things that happen. If we're counting the number of donuts sitting on shelf, I wouldn't call that time. But if we're calculating the number of donuts coming off a Crispy Creme conveyer, then that would be the Time kind of counting. It's better for talking and planning to count things that are regular, like the sunups and sundown. The sun comes up in the morning and we mark an x on the calendar, then we count them up. Same goes for counting the electrons spit off of an atom. it's all counting.

 

[Pilot7]

PILOT7,
I'm not used to writing on things like this. My friend Herm got me to do it. But you're right about the donuts. All the counting has to be of things that happen. If we're counting the number of donuts sitting on shelf, I wouldn't call that time. But if we're calculating the number of donuts coming off a Crispy Creme conveyer, then that would be the Time kind of counting. It's better for talking and planning to count things that are regular, like the sunups and sundown. The sun comes up in the morning and we mark an x on the calendar, then we count them up. Same goes for counting the electrons spit off of an atom. it's all counting.

Hi Selraybob

I think maybe I did a poor job of making my point. It is just that with a lot of things, we don't conflate the counting of X from the X itself (Aristotle's point actually). With time, there is a view sometimes forwarded that there is nothing as such there beyond the counting (or measuring). I'm of a different mind on that for the sort of reasons noted--point being that because we count it ergo it does exist. The question then is WHAT IS IT? One counterargument is that it ONLY exists in virtue that we count it... which then begs the question of whether time ceases to exist when we stop counting it per se... Thus it may be contended that time does exist and can be counted--whatever its eventual real or ultimate nature might be...

I spent a lot of thinking hours on the metaphysics of time (PhD thesis in philosophy of science/physics as it happens). Ultimately I concluded that there are structural qualities time has (not just counting, but metrics, geometries, topologies, etc.) which themselves vary from context to context AND there is something qualitative beyond these structural aspects. What you ask?

1. 'flowing-ness'
2. Direction (not to be confused with asymmetry)

Both of these are QUALITATIVE features, not quantitative. The first is the quality that we count when we count time, the second is a qualitative feature about HOW we do that counting.

I did some further work to get around the basic problems of talking sensibly about time, but will stop here. But anyhow the point here is just that time has to be something beyond the counting and it remains deeply enigmatic.

Cheers!
Pilot

 

[geoffleonard]

could time not just be how we perceive the clockworks of the universe, i know for continuity something has to be 'ticking' the rate of the universe, but maybe time itself is only here because we observed rates and changes. but, does activity depend on time, or does time depend on activity? I believe time exists as a fundamental entity in space such as gravity and mass, but I think it is determined as an entity that exists only because the universe is expanding. if it stopped would time stop, and if time did or didn't stop, would activity stop? Until we witness one or the other i doubt we will ever truly understand time. we will just measure it.

 

[Pilot7]

could time not just be how we perceive the clockworks of the universe...

Yea, maybe. My primary thesis in my dissertation work was that, whatever time is, and whatever 'perspective' IS (in the sense of consciousness or awareness or intentionality or a bunch of other similar philosophical notions), and whatever causality is, they are the SAME at root. In other words, however you choose to view the one will require that you look at the two other kinds of things, metaphysically speaking. Or in yet other analogical words: We don't know what color time, causality and consciousness are, but whatever colour they are, they are all the same colour if you get my drift.

...i know for continuity something has to be 'ticking' the rate of the universe, but maybe time itself is only here because we observed rates and changes. but, does activity depend on time, or does time depend on activity? I believe time exists as a fundamental entity in space such as gravity and mass,...

Not sure what you mean by continuity here--it can mean more than one thing. If time is only here because we observe it (ie rates and changes) the it suggests that it is nothing other than our consciousness or intentionality itself.

Like you say, if time can only exist with activity, they would seem to be intrinsically related as two sides of a three-sided coin (the third being, I argued above, consciousness).

But if it is like you then say that time is a fundamental, I would argue the two views are almost inonsistent. In other words, either time is a REAL THING, or it is a PERSPECTIVE, or perhaps BOTH, but than has serious implications for physics (ie 'consciousness' as a real thing).

...but I think it is determined as an entity that exists only because the universe is expanding. if it stopped would time stop, and if time did or didn't stop, would activity stop? Until we witness one or the other i doubt we will ever truly understand time. we will just measure it.

Not sure why you think the expansion of the universe should have anything to do with time... There is no reason to believe that time 'goes' backwards around a black hole (the equivalent to the big crunch). Time (mostly) seems to correlate well with the entropy gradient--why should entropy follow the universes expansion/contraction? See Roger Penrose on that one. Not sure why our understanding of time is dependent or helped by this knowledge...

Cheers
Pilot

 

[Selraybob]

I read some more posts since I was here before, and the last ones about keeping the minds closed to what's currently accepted. It sounds like Einstein the patent clerk would've been knocked off this site as soon as his fourth dimension quackery hit the page. I sure hope I don't get deleted for saying Time's a count. Aristotle even got that, even though he went off with his own crackpottery with the Now stuff. (I went back and read Physics, so I'd know.) So what I did, because I still haven't read any reasonable theories about why Time's anything but a count, and because I already knew there are people holding tight to the 4th dimension, was put it down in an ebook on Amazon. https://www.amazon.com/dp/B0054EU0IE/?tag=pfamazon01-20. It's 99 cents. I wanted it to be free for now, but my buddy Herm couldn't figure out how to do that on Amazon.

Basically, all the math and all the philosophy and all the research can't make Time anything but a count.

 

[jeebs]

heh, it's been ages since I made this thread, what a can of worms it's turned out to be.

I already knew there are people holding tight to the 4th dimension

I am a bit out of my depth in this discussion, but I've been trying to get into my head a picture of what is really meant when people call time a fourth dimension. It's just something I've blindly accepted to allow myself to do calculations and pass exams. However, I have got a rough sort of semi-idea and wondered if it was an accurate way to imagine it, or if it
really is any use at all:

It's easy to think of what is meant by 3 spatial dimensions, we've got up/down, left/right and forwards/backwards. We get a sense of where we are in space because we can look along all of those axes. However, what if we were blinded to the up/down and left/right axes, so that we were confined to looking only along an infinitely narrow tube? We wouldn't even be able to distinguish our location or which direction we were looking along it - because in "real life" we require points of reference away from the straight line we are looking along to judge where we are when we move along it.

As an example, imagine some point object on this axis our observation is confined to, and it is emitting light in a uniform, regular manner. The only light we ever see from this emitter is the light that travels perfectly along our axis. The photons would "look" exactly the same regardless of our distance from its source; we would need at least 2 spatial dimensions and be able to detect multiple photons to judge the source's intensity - think trigonometry. (we could infact judge our direction motion from red/blue shifts here, but let's ignore this).

Let's move away from photons now to just some arbitrary stationary point objects on this axis that we can only percieve when our location exactly matches theirs. We could move along the axis towards them, but we could never predict when we were about to hit one, because this would require us needing observation of them emitting light (or anything else that conveys their presence) in more than 1 spatial dimension. All we are aware of is that in any "instant" we are either aware of one or we are not.

Wouldn't this be like moving in an extra dimension we call time in that we don't experience "sideways" or "up/down" directions in time, we've only got this one axis we can percieve or sequence of events that we experience?
We can't judge our position on just one single time axis, and find difficulty in imagining our motion along it because for any motion we must first be able to see an initial and final position (hence the whole "time is a manmade construct" school of thought, which I think is a lazy side-step / massive cop-out)?
Does this line of reasoning mean we can literally imagine time as an extra spatial dimension that we move in?

Reading this back I'm not sure I've fully explained what I mean here but this is the best I can express what I'm trying to think of. Maybe I've conveyed enough to be understandable.

 

[MJA]

Time is a tool of human construct to measure the motion of nature.
Unfortunately nature (not only at the micro level but every level) is truly immeasurable.
Physics 101

=
MJA

 

[guillefix]

I think that the idea of time as the forth dimension is the one I like the most. For me the universe is a huge four dimensional object with a certain shape. For some reason this object has some simetries along certain axes and this leads to the laws of physics which describes how points in three of the dimensions "change" along the fourth one. I also think that consciounes is a result of this "changes", causes and effects, thoughts leading to other thoughts, etc. Therefore our consciounes is confined to three dimensions becacuse the points in the fourth dimensional manifold are not "changing", and therefore consciouness of the four dimensions is impossible. Also the feeling o direction of time is caused by the assimetries that this four dimensional object has. Anyway, this is just GR and a bit of phylosophy and I can't claim it is the way the universe really is, I am sure misteries will never end, but I don't fear them.

 

[Pilot7]

Time is a tool of human construct to measure the motion of nature.
Unfortunately nature (not only at the micro level but every level) is truly immeasurable. =MJA

I guess it is true in this age especially that there is such arrogance in many circles to presume all of nature will bow before microscope and telescope, but what still surprises me is that nature does in fact, sometimes at least, let herself be consistently and fairly reliably measured and dressed in theory. Remarkable!

Yes, in a way time is a human construct, but which of our thoughts, ideas, conjectures, descriptions, etc. is not? We create clothing for the universe to wear, and sometimes it fits, at least for some occasions. Amazing!

 

[Pilot7]

Dimension

Just a note on dimension:

Dimension, at its deeper roots, is a topological construct, meaning it is an aspect of a set (usually infinite). When we say a "space" has n dimensions, we are really saying something about the space's underlying topology.

For those unfamiliar with "topology" and "set theory", you can think of it as the structure that is more basic than that part we quantitatively measure. For example, a balloon and a beach ball and a cube all have quite different measures, but all have identical topology. On the other hand, all these differ from a popped balloon, or a piece of paper or square shape, again all three of which have different geometries, but the same topology. Donuts and a torus again are yet another common topological classes differing from the aforementioned. Dimension in this sense is a topological property with obvious implications for geometry and measure (ie we measure things according to their topological dimensions usually, for example width, height, breadth, but also temperature, mass, charge,... and of course *time*)

So what is going on when we say space is 3-D or 4-D (space-time) is that we are judging from experience a smallest number of dimensions consistently to explain some (but not all) physical data. Some people of course contend with various theories that have required 5 dimensions in the universe, or 9 or even 11 (as I believe is in some string theories for example). And if we count mass a primary quality, that certain would be another dimension.

Now this begs whether these dimensions as such "actually exist" or are they simply intellectual constructs used to explain relationships between data? This was in fact famously debated by Leibniz and Newton and remains an unresolved issue to this day with at least three distinct positions one can take on it.

Of course, we may well wish to elevate certain dimensions (those spatial), since not only does this sort of theoretical construct work remarkably well to predict the way cannon balls and maybe space ships to fly, but it also *seems* to our consciousness to be how the world is. We don't directly perceive mass, we infer that, but distance has a kind of immediate quality to our senses.

It is worth noting here, that the kind of space we perceive is pretty well Euclidean--meaning specifically we intuit using the parallel axiom. However, if Einstein is right, our intuitions are of course wrong, but we can only infer this, we do not directly perceive it as the case. The significance of relativity is not (necessarily) a dimensional change to the universe or our best theories thereof, but to an inversion of one of four dimensions so far as measure is concerned. (I guess there are some GTR models that really do change the topology, like Goedel Universes, but even these do not change the basic set of dimensions).

Now with time, we don't have this exactly, though we have some kind of sense of past experience being variously far past and near past or perhaps near future. Whether one wants to ascribe this a dimension in the same way as space is, I suppose, a matter of taste and convention a la the Newton / Leibniz debates. However, in our experience, we not only distinguish between events separated by measurable distances and times, we also experience their immediate alteration/change.

This change appears to be a primary quality of the universe. The measure of such change might be secondary, for example according to the kind of theory we use to calculate such (GTR, STR or classical). But change in and of itself is not (as far as I have been able to see in my research) reducible to any other primary qualities through any going theory of physics, and it really does seem to be there.

Actually, some interpretations of quantum theory do provide for a foundation of change as a *real* collapse of the wave function--and while I personally favour this sort of theory, it does open a number of serious cans of worms relating to the nature of consciousness in the physical universe and so on.

Final note. One of the features of "psychological time" or change is its apparent direction. One of the great errors of even some quite famously clever physicists (like Hawking) is to conflate *direction* with *asymmetry*. Consider the "arrow" below:

------>

The shape is asymmetric, that is to say, one side differs form the other. But is there any intrinsic direction in the shape? If you say it is "pointing" to the right, consider why. Is this not merely the convention we have associated with the shape? Could not a different culture, for example, associate the opposite direction with such a symbol? Or none at all? The moral here is that direction and asymmetry are different beasts, and while all things that have "direction" as a quality arguably also have asymmetry, it does NOT follow that all things with asymmetry have direction...

Hope my post was not inappropriately pedantic or boring or longwinded... :-)

 

[guillefix]

True the asymetries we find in our universe doesn't directly favour one direction or the other, but may be the nature of our consciouness is related to for example the entropy of our brain, may be the bigger the entropy the more information that our brain has about its cause (the past, when the entropy was lower) than its future, say. We know too little about what consciounes is and how our brain works to know the exact mechanism, but I think what Hawkins means is that we can't have direction without assymetry, now which direction depends on other things (in other cultures, other laws of nature for example).

 

[Pilot7]

...may be the nature of our consciouness is related to for example the entropy of our brain, may be the bigger the entropy the more information that our brain has about its cause (the past, when the entropy was lower) than its future, say. We know too little about what consciounes is and how our brain works to know the exact mechanism, but I think what Hawkins means is that we can't have direction without assymetry, now which direction depends on other things (in other cultures, other laws of nature for example).

Yea, this is the question. But while entropy has a funny relationship with information (I guess the latter has been curiously defined as the inverse of the former in certain engineering circles--a definition with a very ironic origin actually), information is not consciousness, or to be more precise, it is not "intentionality" to use one technical term. Interestingly, this term comes from the latin "intendere" (roughly) meaning to "point at". I don't see how entropy or its gradients could, *even in principle*, fully explain what is going on with consciousness or memory or psychological time. True there is much we do not know, but even if we did not know the process by which beer is fermented, we might still reasonably infer that it does not come from an enchanted river upstream... The first part of getting to know about something mysterious is often getting clear on what it cannot be. In this way, IMHO, looking to entropy, and its apparent temporal asymmetry, is very much barking up the wrong tree.

On Hawking, I could dig it up, but actually he is quite confused on certain topics, consciousness and psychological time being one of them. Look up "Hew Price" and "Hawking" and "arrow of time" or some such, there is sufficient literature on it. I know criticizing Hawking is something of a holy cow, but I have been astonished how little weight he gives to consciousness (or philosophy)--he is really an old school positivist in many respects. But that scientific program has some real problems, not just consciousness, but many others. Anyhow, I am (unsurprisingly) not a positivist :-)

 

[sophiecentaur]

You could look upon time in the same way as you can look at Mathematics. They could both just be constructs of our brains to help to explain what we experience. By introducing time into our perception of the World, we have a small chance of feeling that we may 'Understand' a little bit about what is going on (and there, unfortunately) I have had to use an implied 'time' in my explanation. But we have no option. There are forms of Art that portray some processes with the various states presented in the same picture and we can sometimes remember temporal experiences as one entity - for instance, we remember some films and plays as a single entity and it's only when we run over them in our minds or try to describe them that we actually introduce time. Also, we draw graphs with time along one axis but we don't have to wait to see the variables changing - the graph shows them over a range of times all at once.

 

[sophiecentaur]

And, talking of time - didya notice that this is my 3000th post? And it seems only a day or two since my first.. . .
Must crack upen a bottle of fizzy water tarrraaa .

 

[Pilot7]

You could look upon time in the same way as you can look at Mathematics. They could both just be constructs of our brains... There are forms of Art that portray some processes with the various states presented in the same picture and we can sometimes remember temporal experiences as one entity...

Yes, could be... BUT, roughly in the words of Lotze, either we need to explain the nature and origin of an illusion or accept that it is more than illusion. Yes, the raw experience of process and change might well be due to our curious perspectives as human beings, but this remarkable illusion itself cries out for explanation. For example, the color of red has no direct correlate in the physical world, beyond its tentative association with a certain frequency of EMR, which upon closer analysis is quite superfluous to the experience itself (all one needs to do is excite certain cones in one's retina to produce the experience of red). In the same way, our explanations are quite lacking until we can find some kind of theory to account for this phenomenon.

Process itself is a very atomistic notion often overlooked. If indeed it is not a fundamental feature of the cosmos, which is to say that the cosmos is in itself static, I find myself troubled indeed to explain how such could even in principle be derived from any set of static components whatsoever.

Kant came closest to giving time a basis in reason in some ways, which is roughly what you are suggesting, that the phenomenal empirical world does indeed appear to be temporal, mostly because of a faculty he called the "intuition". And like you, Kant suggests that the noumenal, real world, which mostly lies outside of our intuitive faculty to discern, is... somehow perfect, Platonic, and unchanging. However, it is a part of his reasoning that definitely depends on a "miracle", for whether one tries ontologically to reduce consciousness to a static cosmos, or if one tries, like him, to explain epistemically how the universe must be to account for our experience, process itself is like a big hot coal that one can neither swollow away nor spit out.

But yes, for God, perhaps in His/Her perfection beyond the celestial sphere, time and process as we know it have no meaning... But how He/She gave rise to the cosmos... replete with process? Miraculous, indeed!

(BTW I am waxing poetically here with strong metaphors)

It might be added that if, on the other hand, one does regard process as essential, even to God, then we are really going to have to rework how some of our best physical theories work. On the other hand, given the incongruence between our best two theories (QM and GTR), perhaps we haven't lost so much as we thought anyways!

 

[sophiecentaur]

"Perfect, Platonic and unchanging" are terms which I feel to be a bit loaded and angled to shoot dead any serious arguments along my lines before they are started. I do have a problem with quoted ideas from Philosophers from hundreds of years ago. With the best will in the world, these guys were not aware of a lot of evidence that has emerged long after their deaths. Whilst I totally respect their intellect, I can't always understand how their ideas are so often used out of the context of 'their' worlds.

If the expression ''relationship between quantities" is used as a substitute for 'process' then time (a very elastic quantity in any case, now that we use Relativity) may not, in fact be regarded as any more than a construct. But, there again, perhaps we could say that about a lot of other ideas too.
Time I went to bed now!

 

[Pilot7]

Well it looks like my response got eaten by the entropy deamons in the void...

"Perfect, Platonic and unchanging" are terms which I feel to be a bit loaded and angled to shoot dead any serious arguments... Whilst I totally respect their intellect, I can't always understand how their ideas are so often used out of the context of 'their' worlds.

Such admittedly extreme terms are not intended as straw men, rather the opposite. I am quite open to looking at another term, a more relaxed sort of theoretical proposition of some sort. I ask myself then: How does this term differ from the sort of extreme paradigm above? If a difference can be shown or even suggested, then I look further there, because that is likely going to be the source of new and better understanding.

I think there may be something of a culture gap here (philosophy/physics)--often certain schools of thought or some idea is associated with its founder, who might well actually have had quite a different view on the matter. For example Plato and what we have since come to associate with Platonism, which itself means quite different things in various contexts (eg mathematics, physics, ethics, etc.). But this is also done in physics, though less often since most of the best physicists also happen to be relatively recent. But by example, consider the expression "Newtonian Physics" or "Newtonian space" or "Newtonian time". Yet, were to actually go back and look at Newton's words, we would find a diverse number of ideas that seem quite foreign to what we now normally associate with the above terms. For example Newton says of time:

Absolute, true and mathematical time, of itself, and from its own nature flows equably without regard to anything external, and by another name is called duration: relative, apparent and common time, is some sensible and external (whether accurate or unequable) measure of duration by the means of motion, which is commonly used instead of true time ...

Similarly, we will find other oddities with space and physics itself. His calculus is not even used today (we use Leibniz's notation and arguments). And similar cases will be found with other pre-20th century physicists (eg Galileo, Copernicus,... Archimedes, etc.) Aristotle is usually really tossed under the bus for some of what he said in most freshman physics textbooks, which is a pitty, since his ideas were in many places quite a bit more sophisticated. Anyhow, for sure, we need to bear such context in mind when we read such old sages and when we talk about contemporary views that are associated with whichever figure.

Perhaps the two views of time as we have toying with here are best rendered as the "Heraclitean" and "Parminedean" views, but it is dubious we can say either person really held the views we now associate with them in any detail. (Indeed, how would we know, we have barely more than a page of rather cryptic writing from either of them to tell us!)

If the expression ''relationship between quantities" is used as a substitute for 'process' then time (a very elastic quantity in any case, now that we use Relativity) may not, in fact be regarded as any more than a construct. But, there again, perhaps we could say that about a lot of other ideas too.
Time I went to bed now!

This gets to the heart of the issue as best as I can tell. I am not ready to accept that:

process = relationship between quantities

I am not even ready to accept that

process = a quantity.

I will accept that:

experienced process = a quality

and it may be that:

process (in itself) = a qualitative feature of the cosmos that is static

but I want to know how such an illusion resolves or reduces ontologically speaking. Even in principle, even as a hypothesis or a guess of a shadow of a guess of it might look.

But for sure I cannot see how:

process (in itself) = a quantity (of anything)

that just doesn't even make sense to me.

Perhaps you can elaborate?

For now, I wish you good dreams.

 

[sophiecentaur]

Fair enough on the Philosopher bit. Of course, using their names as a description is fully justifiable. Was I being too prickly? Possibly - but I am going through an "annoyed by Philosophers" phase - a separate issue and my problem entirely!
What I am getting at is, of course, only statable as as an analogy. Our apparent 'motion' through time needs to be no more than 'apparent' and a convenient ruse to help with understanding. My tie-in with Maths applies here because Maths is a very similar thing which can be thought of as external to the real world but which gives us a way of understanding things.

If you plot a graph of the path of a projectile in horizontal and vertical planes, the whole process (/ situation?) is there, in front of you with no reference to time at all. If you want to plot it from the results of the equations of motion, as we know them, then x and y displacements are related to time. but the relationship between them doesn't include time. You could plot a number of trajectories on the same piece of paper but they could be describing different situations at very different (what we call) times. We don't need to know the times at or the order in which which any measurements were made. So time is, in a sense, outside, the description.
Could it be that the only thing that could make time something more than 'just Maths' could be the fact that we all agree on the direction in which we are using it and that all our experiments seem to indicate a single arrow of direction?

I appreciate your struggle with the definitions at the end of your last post. We are approaching the regions of "what do we mean by mean by mean?" (was it Monty Python?).

 

[Demystifier]

All the confusion about time stems from the existence of two different notions of time, only one of which has to do with physics:
http://www.fqxi.org/data/essay-cont...f?phpMyAdmin=0c371ccdae9b5ff3071bae814fb4f9e9