Why is time special?

[mdwh]

I'd say that we perceive time as having an arrow due to the way that our memories fill up - if my consciousness suddenly lept back in time 10 years ago, I would not experience that, because my brain would then only have the memories from 10 years ago, and not today.

Why do we move through space as the clock ticks constantly, instead of moving through time as the meter-rule slides?

It doesn't though - according to relativity, the clock slows as an object moves faster.

Even though we may not be able to travel back in time, it seems that time is some actual property of the universe, and not some "background" thing that events take place in.

 

[Kyriakos]

Apart from a very basic mathematical concept (it is only a variable there), and a more important concept in physics, time is a hugely important concept philosophically.

Consciousness has already been mentioned in the thread. Everyone can sense that one hour before this moment it was the past, and although if that past was not very different from the present we can still view it as part of the same 'period' (which could be even nameless if not so significant/nothing much going on) still we can immediately identify it as a different point in time than the present.
Do not that 'living in the present' is not a common experience. Some people do not live much in the present, that is they are in deep thought about the past, and have only a smaller impression about the 'here and now'. The 'here and now' is also a state of moment however, mostly characterised by lack of thoughts, and an increase of sensory perception. Ofcourse even so, sensory perception doesnt mean that the state of consciousness is a 'present' anymore than it could be a 'past', since what is more important is the individual's sense of the 'present'.
Definately the 'present' is not experienced in the same way by any two people. In this way the notion of it is specific to each individual, and it is built on top of other mental states particular to him/her.

However what is common is the universality of the 'direction of time'. Time does have a direction, although that direction is hard to conceptualise. As we can immediately identify which direction is to our left or right, similarly we can immediately identify which direction is to the past, however this does not happen as carefully so that we can present the psychological concept of time in detail. But definately any notion which we can immediately identify we can immediately identify due to a lower ground of thought where that concept is very detailed, and it is only the effect of the fact that we are moving in a level of consciousness which is above that lower ground that we only get to sense the ability to identify the notion, but not to describe it.
The mind does the infinitely larger part of its work without immediate consciousness taking care of it. Only a very small fraction of the mind's workings are presented in some detail (not at all in all detail) in the immediate level of consciousness, and yet due to the fact that those lower levels exist we can have access to a wealth of notions and concepts, like set direction (right and left), time, the sense of a future/goals and in general all of the other notions, since there isnt a signle notion that we actually manage to analyse in full detail.

 

[Birdjaguar]

@BJ: You are still missing the point. The point is not that there is a before and after (which is just an ordering issue - we can have before and after in space dimensions too; in the line from here to Saturn's orbit, Mar's orbit comes before Jupiter's orbit), but that in the time dimension the before and after cannot switch places always (they can sometimes) (like in space, draw the line from Saturn to here and Jupiter's orbit comes first). Why am I failing to communicate?

The problem may be because I am thick headed at times and can be quite clueless. Just ask my wife.

I do understand that ordering sequence is not an issue here. I do not question that. We seem to diverge on the time issue. You seem to say that the problem is "Why is there a before and an after?" Or "Why can't we reverse time?" I start with a given: there is change. It is fundamental to the universe.

That is a circular definition. The question is why is there a before and after? You cannot explain the arrow of time while using it in the explanation itself. As for change, you can have change without time. Pressure changes with Volume (independent of time), potential energy changes with position (independent of time), etc. etc. Even when the change is w.r.t time, the problem is not with the change, but with the direction of the change. If all changes were perfectly reversible then also we will not have a arrow of time. So theoriticaly we can have time, change and still have no arrow.

Since all changes are not reversible, doesn't that mean that, at our current level of knowledge, the arrow of time is fixed? If it is fixed, then it is fixed either by chance or for an unknown reason? In theory, anything is possible, even an invisible pink teacup god in a bejeweled heaven.

I'm not sure we agree on what is time. I say it is merely a way to calibrate intervals of change and only exists because there is change. Time is dependent on change and is only meaningful through our ability to recognize and measure intervals of it. Am I correct that you are working off some other definition?

For me the question of reversing the arrow of time is trying to simultaneously reverse every nanosecond of change at every level of physical existence (quark to cosmic) thoughout the entire universe to some exact prior state. Pretty awesome task.

So I think we are, perhaps, talking past one another. You about why we can't go backward and I about how time fits with change. BTW, you never did explain why my previous post on time was circular. I don't see it, but I am not very good at ferreting out such things in my posts.

 

[Birdjaguar]

@varwnos: Can you offer up a definition of time?

 

[warpus]

IIRC, isn't that the starting point for the big bang?

I do understand "not liking" the argument and I am open to other suggestions.

My theory is that time is a dimension - kinda like the dimensions of space - but somehow progressing in one direction only... which is where the real mystery lies: What is the nature of the arrow of time? Is it imaginary, or is it real - and if it's real, what does it imply... and how come none of our equations "pick" a direction?

I would even suggest that there isn't just one dimension of time - and that there might be more - ones we can't detect or experience.. but that's just speculation.

 

[Kyriakos]

BJ: such a small task

Well, i am not prepared, and definately this will not be the final word on it (there are large philosophical books about this btw, like "Being and Time" by M.Heidegger) however i could say that:

The notion of Time is one of the more basic (in regards to the fact that they can in some form be readily identified) variables in how we organise our thought. If you start reading this paragraph you will immediately recognise that when you were reading its first senence it was earlier than when you had reach to this point, and looking at the not yet read words below this part of this sentence you can easily calculate that when you would have read them time would have passed from now once more. However in this way we can see that Time is part of every thought, and infact it is a central variable of its evolution. This is not as much part of the actual evolution of the thought itself, since a thought evolves as a mental movement, and therefore we are walking inside our brain towards another point where the thought guides us to. However the notion of Time continues to affect the ability to form a thought, since had we not had a concept of Time (not an analysed one, just an instinctively understood one) we wouldnt be able to form thought progressions. On the other hand it seems a lot more probable that the actual ability of man to form thought progressions preceded the naming of a concept of time, since one would have to assume that from the time of early prehistoric human-like creatures there were types of basic thought-progressions, but not a concept of Time, and then again it is highly probable that there had been a concept of the direction of Time.
Time and the direction of Time however, in philosophipsychological terms appear to be unseperable, since without a before (ie a movement to one side) a now (a lack of movement) and an after (a movement to the other side) there could be no sense of Time. This tripartite form of Time ofcourse has influenced all sorts of cultural evolutions, for example it is accepted in essay writing that one has to have a Prologue, a central part, and then an epilogue. The Prologue is a movement linking the central part with the already established, which is similar in movement to the past. The central part is linked to the present, since it is the core of the essay, the new thing which we now are reading, in real time. And the epilogue tries to provide the reader with something to keep in mind in the future, from the essay, and inevitably after the epilogue the future begins, both for the essay writer and the essay reader. However the tripartite form of Time reveals an interesting fact about central mental movement types of all sorts, since there are three parts for example also in other fuctions. For example: one can focus on a subject, establish a connection with it, or leave it.
Time exists in every thought, and moreover exists in deeper levels, as for example the way a thought pulsates, expands, twists and turns. One could establish it as a refference point for the observation of other concepts in the world of thought, or alternatively use othe concepts so as to examine Time. The fact that the way our consciousness is organised is not based on its immediate level (where the notion of Time also is to be found as an instinctively understood notion) makes it impossible to examine this notion carefully without first seeking a refference point below it, in the realms of the unconscious, from which all thought formtions reach to us.

ps: i know that i didnt provide a definition of Time afterall

 

[Birdjaguar]

My theory is that time is a dimension - kinda like the dimensions of space - but somehow progressing in one direction only... which is where the real mystery lies: What is the nature of the arrow of time? Is it imaginary, or is it real - and if it's real, what does it imply... and how come none of our equations "pick" a direction?

I would even suggest that there isn't just one dimension of time - and that there might be more - ones we can't detect or experience.. but that's just speculation.

No comment on the Big bang and its dimensionless beginning?

My problem with time as a dimension is that making that assumption doesn't get you anywhere. What does it explain that is not previously explained? Does it answer any question?

Now ask the question "Is there any evidence that there are more than three dimensions?" Yes, but time is not necessarily the next one. In Flatland there are hints of the vertical. In Relativity space is curved, that curve implies some other "space" into which our space goes or is distorted into. A transient bump in the plane of Flatland. Perhaps a fourth physical dimension. We will have to wait and see.

 

[Birdjaguar]

ps: i know that i didnt provide a definition of Time afterall

Interesting, as usual, but yes, not a definition.

 

[warpus]

My problem with time as a dimension is that making that assumption doesn't get you anywhere. What does it explain that is not previously explained? Does it answer any question?

Introducing time as a dimension makes the math make sense - a lot more than the math without it.

 

[Birdjaguar]

So the highest and best use for time is as a math variable? Math is a useful tool created by humans to figure stuff out. Adding a variable called time indeed does help solve math problems, but that role is little different than my allocation of it to a calibration system ticking off the changes going on all around. So does this mean we are in agreement?

 

[Bill3000]

They would have to be stopped too. I used absolute zero for convenience sake. I'm not sure we know if quantum activity stops there. If there happens to be a sub quantum level of "stuff" that makes up quarks and leptons, then all of that would have to stop too. My contention is that time is dependent upon the most fundamental and basic "activity" (which is change) of the universe whatever that is.

No, absolute zero means the level in which there is no energy to take away from the system. There is still energy left in a system whose temperature is absolute zero, and this is absolutely true in quantum mechanics. It is most certainly not stopped.

 

[Birdjaguar]

No, absolute zero means the level in which there is no energy to take away from the system. There is still energy left in a system whose temperature is absolute zero, and this is absolutely true in quantum mechanics. It is most certainly not stopped.

Thank you for that correction. Is there a level of "cold" at which we know electrons stop spinning or other sub atomic particles stop moving at all?

 

[Mise]

Thank you for that correction. Is there a level of "cold" at which we know electrons stop spinning or other sub atomic particles stop moving at all?

No, although technically, electrons are point particles (i.e. they have no physical extent), and hence don't really "spin" (spin is an intrinsic property of a particle, like charge or rest-mass). We also know that a particle can, fundamentally, never be stationary at a definite position, due to the uncertainty principle (i.e. if we know it to have zero velocity, we have absolutely no idea where it is, and "is" everywhere simultaneously). If we then find out where it is, it must have a finite non-zero velocity.

 

[warpus]

So the highest and best use for time is as a math variable? Math is a useful tool created by humans to figure stuff out. Adding a variable called time indeed does help solve math problems, but that role is little different than my allocation of it to a calibration system ticking off the changes going on all around. So does this mean we are in agreement?

I'm talking about the equations we've devised to model the Universe with. They work incredibly well - implying that they must be good approximations of reality. Time is a variable in all of these equations. If we extrapolate from the equations it is implied that time is an actual dimension and not just something we invented to measure the passage of .. time with.

 

[Bozo Erectus]

This looks like as good a place as any for this question: Without Time, there can be no Space, but can there be Time without Space?

 

[warpus]

Without Time, there can be no Space

Why do you say that?

 

[Ayatollah So]

@Mise: As you point out there are three known arrows of time (totally unrelated). The thermodynamic arrow of time (increasing entropy), the cosmological arrow (expanding universe), and the so-called psychological arrow (we remember the past).

Curiously, the first two point in the same direction. Currently, there is no known law of physics which would require them to do so. The best explanation why they do is probably a anthropic explanation.

I'd prefer no explanation.

Here's an analogy. Say I toss a fair coin two times. And say that it comes up the same both times. And now some fool demands an explanation of that fact. Why is it that the two "arrows of the coin" both point in the same direction? Why, why, why?

But why should anyone feel compelled to answer that question, other than by saying, Why Not? After all, if the two coins had landed oppositely, the fool would have demanded an explanation of that fact.

 

[Souron]

No, absolute zero means the level in which there is no energy to take away from the system. There is still energy left in a system whose temperature is absolute zero, and this is absolutely true in quantum mechanics. It is most certainly not stopped.

Not quite. Absolute zero is what it is: No motion or energy in the system.

Quantum macanics simply mandates that no point in space can be at absolute zero. The uncertainty principle prevents it.*

*though not in the way you might think.

 

[BCLG100]

because you never have enough time when you want it but always too much time when you dont...

 

[Birdjaguar]

No, although technically, electrons are point particles (i.e. they have no physical extent), and hence don't really "spin" (spin is an intrinsic property of a particle, like charge or rest-mass). We also know that a particle can, fundamentally, never be stationary at a definite position, due to the uncertainty principle (i.e. if we know it to have zero velocity, we have absolutely no idea where it is, and "is" everywhere simultaneously). If we then find out where it is, it must have a finite non-zero velocity.

So we have conflicting pov on absolute zero, what it means and if it has any effect on quantum particles.