The present time

[owl]

In whose reference frame do they occur simultaneously? And why is this particular reference frame "special"?

Please re-read my comments on presentism (and research the topic in general.) Presentism asserts that the present IS now happening everywhere simultaneously. Now, the ongoing present does not depend on frames of reference, as does relativity's assertion that reality depends on the frame of reference from which events are observed.

In fact, presentism posits a universal now without a "frame" around it at all.

[IM Egdall]

Please re-read my comments on presentism (and research the topic in general.) Presentism asserts that the present IS now happening everywhere simultaneously. Now, the ongoing present does not depend on frames of reference, as does relativity's assertion that reality depends on the frame of reference from which events are observed.

In fact, presentism posits a universal now without a "frame" around it at all.

 

 

So if your conjecture is science, not just philosophy, make a testable prediction based on your theory -- a precise prediction for an experiment or measurement that has yet to be performed.

 

When and if your prediction is validated by some one else's observation, and independently verified, then I will stand up for the validity of your theory.

 

If you have no new prediction, then you are only arguing about your opinion, not science.

[Mystery111]

So if your conjecture is science, not just philosophy, make a testable prediction based on your theory -- a precise prediction for an experiment or measurement that has yet to be performed.

 

When and if your prediction is validated by some one else's observation, and independently verified, then I will stand up for the validity of your theory.

 

If you have no new prediction, then you are only arguing about your opinion, not science.

 

 

Presentism is probably the closest interpretation to Einsteins vision of time. It has it's place in science.

[owl]

So if your conjecture is science, not just philosophy, make a testable prediction based on your theory -- a precise prediction for an experiment or measurement that has yet to be performed.

 

When and if your prediction is validated by some one else's observation, and independently verified, then I will stand up for the validity of your theory.

 

If you have no new prediction, then you are only arguing about your opinion, not science.

Presentism is not 'my theory' or 'my opinion.'

I think that you don't appreciate the significance of 'the philosophy of science'* as a tool with which to examine the assumptions of any given scientific theory.

*("...not just philosophy.")

 

On a lighter note (very little humor), I "predict" that (excuse the 'shouting') presentism will prevail: "NOW IS THE ONGOING PRESENT EVERYWHERE"... will eventually debunk the relativity dictum ('dogma' may be too strong...) that reality everywhere depends on the frame of reference from which it is observed... that "everything is relative" (including simultaneity) and that "there is no preferred frame of reference."

Again, imagine that no intelligent life or observers ever evolved. The cosmos would remain as it is, objectively, intrinsically, and independent of from which frames of reference it is observed.

[MigL]

There is no such thing as the 'philosophy of science'. There is only science, and what you are going on about is philosphy, a totally different beast. As IM Egdall has explaned, science poses a theory, makes predictions, and is then tested for validity. If the predictions don't pan out the theory is untrue or unfinished. I and countless others believe SR and GR have been extensively tested and verified. There is no global NOW !!

 

Again, as IM Egdall has stated, why don't you investigate what predictions the notion of a global NOW would imply, and see if any of them hold up logically or experimentally, and wether they contradict known-true or estabilished facts and phenomena.

[michel123456]

There is no such thing as the 'philosophy of science'.(...)

http://en.wikipedia.org/wiki/Philosophy_of_science

[swansont]

!

Moderator Note

owl, you have been told before in this thread that this is a science discussion; non-science discussion should take place in another thread.

[owl]

!

Moderator Note

owl, you have been told before in this thread that this is a science discussion; non-science discussion should take place in another thread.

Umm... This thread is "The present time" and my last post was on presentism. ???

Is it forbidden in a science discussion to examine fundamental assumptions about the nature of time, like "What is it?"

 

Anyway, in an attempt to avoid being banned I will hereafter keep all my comments about time in my Ontology of time thread.

[swansont]

Umm... This thread is "The present time" and my last post was on presentism. ???

Is it forbidden in a science discussion to examine fundamental assumptions about the nature of time, like "What is it?"

 

The thread is posted in the physics section; if the originator wishes to discuss philosophy or speculation, s/he is free to post a question in the appropriate subforum. If you contend you are discussing physics, perhaps you can point me towards "presentism" in physics texts, and re-evaluate your justification in light of your note that your position "contradicts relativity's claim that simultaneity is relative to the velocity".

 

Anyway, in an attempt to avoid being banned I will hereafter keep all my comments about time in my Ontology of time thread.

 

Yes. See that you do.

[PeterJ]

As I see it, if the past and future do not exist then the present 'instant' cannot have a duration. Same problem as for infinitessimals ('ghosts of departed quantities' etc). Hence one physicist argues against Zeno by citing the impossibility of 'instants'.

 

So I don't really understand how is possible to have an experience of the present, and wonder whether in fact we do, or whether what seems to be an experience of the present is in fact a mixture of short-term memory and anticipation. Iow, our present experience in the world of change is some sort of fantasy. This chimes with the experience of those who study psychological time, which seems to be that when awareness becomes sufficiently, 'focused' or 'single-pointed' then time ceases to pass and is seen as a psychological phenomenon. Ditto space. Thus for the sage (so they say) there would be 'no other time than the time he is in.' Such a view would require a double-aspect approach to the universe, conceptually a little like the classical/quantum dualism, giving us a theory of 'two worlds' or 'two truths'.

 

If such Buddhistic thoughts are unwelcome here just say so. I am not proselytising. But it does seem to me like we need some new ideas and this would be a source of a few. The Abbhidamma literature speaks extensively about the nature of time, but it is rarely honoured by any proper analysis by physicists. Maybe, just maybe, it would stand up to such an analysis. Davies has had a few mentions here and he speculates much the same, so while this may be a distasteful speculation it is probably not crackpottery.

 

The 'mystical' view, by which I mean that derived for from what you guys generally take to be 'navel-gazing', would be, I think, that the reason why we cannot understand time and space is that we insist on reifying phenomena that have no true existence. Once we've done that we are inevitably unable to make sense of their existence or nature. Our initial axioms would be impossible to reconcile with the data.

 

Just shooting the breeze...

Edited November 5, 2011 by PeterJ

[owl]

As I see it, if the past and future do not exist then the present 'instant' cannot have a duration.

See my reply in the Ontology of Time thread.

[PeterJ]

Okay. Let's hope I can find it. Or could you copy it over?

[owl]

Okay. Let's hope I can find it. Or could you copy it over?

Speculations section:

http://www.scienceforums.net/topic/54529-ontology-of-time/page__pid__636795__st__300#entry636795

[swansont]

Speculations section:

http://www.scienceforums.net/topic/54529-ontology-of-time/page__pid__636795__st__300#entry636795

 

!

Moderator Note

Rule 5: you shouldn't use scientific threads to advertise your own personal theory

 

You kept your promise for a whole day.

[DrRocket]

Please re-read my comments on presentism (and research the topic in general.) Presentism asserts that the present IS now happening everywhere simultaneously. Now, the ongoing present does not depend on frames of reference, as does relativity's assertion that reality depends on the frame of reference from which events are observed.

In fact, presentism posits a universal now without a "frame" around it at all.

 

Thank you. That makes the situation quite clear.

 

The ample evidence supporting relativity show that "presentism" is utter rubbish, with no basis whatever in science.

[PeterJ]

Hmm. That surprises me, given the widespread support for presentism. I would have thought it was consistent with the data.

 

 

 

 

[Mystery111]

Hmm. That surprises me, given the widespread support for presentism. I would have thought it was consistent with the data.

 

 

 

 

 

I wasn't so surprised to read Dr Rockets analysis on the situation. When I first came here, I began to teach time in accordance to (but not fully) presentism. I don't support all the views held by it, but what I did understand was there could only be an eternal present. This is true to physics and what is a relative fact is that past and future ceased to exist. Time as we knew it began to vanish from the theory and did completely vanish when taken to scales of the universe - this is the way it is because of a known constraint of the universe Hamiltonian called the Wheeler de Witt equation. It succesfully describes a non-changing universe, where time no longer can describe moving clocks.

 

Dr. Rocket said ''utter nonsense'' in response, and I said to him he was entitled to his own opinion on the subject, but it wasn't taken any further. So as much as you were surprised, I knew he didn't like presentism or an eternal present at all.

Edited November 6, 2011 by Mystery111

[md65536]

Hmm. That surprises me, given the widespread support for presentism. I would have thought it was consistent with the data.

I don't see how it is not. http://en.wikipedia.org/wiki/Presentism_(philosophy_of_time)

 

A word of caution: No one's right all the time and worse, certain members like to use their own definitions of whatever words and concepts they choose, without bothering to tell anyone that they're using their personal definitions. I don't think the accepted use of presentism includes that "the present is universal and identical for all observers".

 

As far as I know, presentism is not inherently incompatible with relativity.

 

However, I believe that an instantaneous universal "now" is incompatible with relativity.

Relativity of simultaneity implies that what is simultaneous for one won't be simultaneous for all.

Thus, anything simultaneous with a hypothetical "universal now" according to one observer will not be simultaneous for all observers.

If "now" includes events that aren't simultaneous, then it contradicts the "time is not extended" meaning of presentism.

[Mystery111]

I don't see how it is not. http://en.wikipedia....osophy_of_time)

 

A word of caution: No one's right all the time and worse, certain members like to use their own definitions of whatever words and concepts they choose, without bothering to tell anyone that they're using their personal definitions. I don't think the accepted use of presentism includes that "the present is universal and identical for all observers".

 

As far as I know, presentism is not inherently incompatible with relativity.

 

However, I believe that an instantaneous universal "now" is incompatible with relativity.

Relativity of simultaneity implies that what is simultaneous for one won't be simultaneous for all.

Thus, anything simultaneous with a hypothetical "universal now" according to one observer will not be simultaneous for all observers.

If "now" includes events that aren't simultaneous, then it contradicts the "time is not extended" meaning of presentism.

 

I know this was directed at another poster... I'd like to say I agree. There can be no universal now... But keeping that aside, presentism is still very compatible with every other idea of relativity. And the incompatibility could not be on a worse subject. Time is frought with controversy, and relativity itself makes a lot of controversial claims itself on time, many of those statements are in complete agreement with presentism.

[Iggy]

...Dr. Rocket said ''utter nonsense'' in response... I knew he didn't like presentism or an eternal present at all.

Are all events simultaneous in an "eternal present"? If so, it isn't an eternity. If not, it isn't a present. Either way, I can't personally make sense of "eternal present".

[Mystery111]

Are all events simultaneous in an "eternal present"? If so, it isn't an eternity. If not, it isn't a present. Either way, I can't personally make sense of "eternal present".

 

An eternal present simply means, the present time is all that is ever in existence. The universe may end in the future, in which case obviously time is not as eternal as we might like to think...

 

The difference with the way I view the eternal present (the time which is asymototically experienced by any observer) to the way presentism believes the present time, is that presentism believes the past and future are happening ''right now''. I don't believe this is the case at all, or atleast it is greately misunderstood. In some sense, relativity would have to permit that the past was happening now, due to allowing time travel to be a possibility. If you could travel to the past, in this theory you would end up in the past (in it's present time sphere). But as far as anyone is concerned in the past, our future is yet to happen, and this is true.

 

There are some truths to presentism; Time may be viewed as one large timescape where only the present moment happens. This is as close to nature as we can test. It is true every moment we experience is simply the present time, no such distinction as a past or future really exist in physics. For a past to be happening ''now'' goes against the idea that a past does not exist alongside our own existence. I think the present moment is very much an issue of frame depency.

Edited November 7, 2011 by Mystery111

[Iggy]

A word of caution: No one's right all the time and worse, certain members like to use their own definitions of whatever words and concepts they choose, without bothering to tell anyone that they're using their personal definitions. I don't think the accepted use of presentism includes that "the present is universal and identical for all observers".

 

As far as I know, presentism is not inherently incompatible with relativity.

Yes, I couldn't agree more. Literally.

 

Presentism is so vague...

 

Presentism is the view that only present objects exist. More precisely, it is the view that, necessarily, it is always true that only present objects exist.

 

http://plato.stanford.edu/entries/time/#PreEteGroUniThe

So what? Abraham Lincoln doesn't exist in the present. Fine. I think relativity can live with that.

 

An eternal present simply means, the present time is all that is ever in existence. The universe may end in the future, in which case obviously time is not as eternal as we might like to think...

 

The difference with the way I view the eternal present (the time which is asymototically experienced by any observer) to the way presentism believes the present time, is that presentism believes the past and future are happening ''right now''. I don't believe this is the case at all, or atleast it is greately misunderstood. In some sense, relativity would have to permit that the past was happening now, due to allowing time travel to be a possibility. If you could travel to the past, in this theory you would end up in the past (in it's present time sphere). But as far as anyone is concerned in the past, our future is yet to happen, and this is true.

 

There are some truths to presentism; Time may be viewed as one large timescape where only the present moment happens. This is as close to nature as we can test. It is true every moment we experience is simply the present time, no such distinction as a past or future really exist in physics. For a past to be happening ''now'' goes against the idea that a past does not exist alongside our own existence. I think the present moment is very much an issue of frame depency.

I am positive of only 2 things. 1) you didn't follow what I meant. 2) I have no idea what you mean.

 

"Eternal" is a very long time. "Present" is a very short time (you can see the first paragraph of the latest link given by md65536 in this thread to see why this is necessarily true). So, putting "eternal" and "present" together would seem to be nonsensical. It's like "dry rain" or "dense vacuum".

 

I would need specifics to understand -- not generalizations. That is why I asked if all events are simultaneous in the "eternal present". That question, if you could answer it, might explain better what you mean.

[Mystery111]

Yes, it may seem like an oxymoronic term.... nothing oxymoronic though, just an expansion of imagination required!

 

Eternal may be something which repeats itself, or something which extends into infinity. In theory, you can have an infinity of present moments all existing but not preceeding or proceeding any other moment... for instance, suppose we quantized time in such a way that all of existence was just frame after frame of tiny stops and starts which equalled the Planck Time. You'd have a fantastically large collection of present moments, an eternal collection of them perhaps.

 

Do all these moments exist simultaneously...? I don't think so. But just because a series of present moments do not exist simultaneously should not mean there is any easy chronological arrow which we can use.

Edited November 7, 2011 by Mystery111

[Greg Boyles]

Mystery111,

 

 

You seem to not understand what I meant very well. I think you and I are in closer agreement than you think.

You say:

 

 

I agree that "there IS only the present." But It makes no sense (to me) to say, "It is not that the future is not yet present and the past is not still present." (my bold)

 

The Einstein quote said that ..."...the distinction between past, present, and future is only a stubbornly persistent illusion." The distinction is that "future is not yet present and the past is not still present"... and in between them IS the ongoing present.

He did not, of course, believe that time is an entity, and with that we both agree. He once said that if all matter disappeared, time and space would also disappear. Of course, moving matter requires "elapsed time", without making it an entity. (I dispute that space would disappear. It would just become empty space.)

 

 

 

Huh? Everything in the cosmos IS in motion, with our without clocks.

(Of course, in the general sense, everything moving IS a "clock.)

 

 

 

How so? Or maybe this post clarifies what I meant.(?)

 

 

If the universe retainied its present size but all matter and energy vanished, then how could we say with certainty that time would cease to exist. Granted there is no easy way to discern events moving across the ruler of time with not matter and energy, but that does not necessarily mean that time is still not there.

 

The only way that time could disappear would surely be if the universe entered contraction back to a singularity.

[Mystery111]

But I would like to add... Whilst the past is not happening right now, the past does have a now that is happening.

 

If the universe retainied its present size but all matter and energy vanished, then how could we say with certainty that time would cease to exist. Granted there is no easy way to discern events moving across the ruler of time with not matter and energy, but that does not necessarily mean that time is still not there.

 

The only way that time could disappear would surely be if the universe entered contraction back to a singularity.

 

Without two bits of matter, you have no acting clocks. In a universe devoid of matter, where are your clocks so you can make measurements?

 

It's all about relativity.