[owl]

michel123456, on 26 October 2011 - 08:28 PM, said:

But you must know that true present is not observable. What we believe is present is in fact the past.

As I said:

Quote

In presentism there are no local boundaries around "now" even though it 'takes time' for one location to "see what's happening now" in another location.

As a psychologist having studied the physiology of perception, I well know that, even with an event happening right in front of our faces, "it takes time" for a visual image of 'what IS happening' to reach the visual cortex and be "experienced" as "now happening."
In that sense, I agree. Our experience of "now" always has a signal delay factor between the "now happening" event and our "now experiencing" that event.

Same principle holds for longer distances between event and perception of event, but that does not deny that the universal present is now happening everywhere.
My favorite example is that a flare on the Sun happening now will take 8+ minutes to be seen on Earth, but that does not deny that "the present" IS now, simultaneously happening both here and there. This, of course, contradicts relativity's claim that simultaneity is relative to the velocity, etc. of all different frames of reference... (that all "reality" depends on the frames of reference from which events are observed.)

[md65536]

owl, on 27 October 2011 - 06:15 PM, said:

As a psychologist

What certification, degree, or license do you have? I ask this as it would back up your claim of expertise.

[owl]

md65536, on 27 October 2011 - 07:02 PM, said:

What certification, degree, or license do you have? I ask this as it would back up your claim of expertise.

None of your business. I value my privacy and a good bit of anonymity for good reasons of my own. That's why I didn't share any biographical info when I joined this forum. I always tell the truth (as I know it, of course), and I don't care a whit whether or not you believe me.

[michel123456]

Mystery111, on 27 October 2011 - 03:12 PM, said:

Real physical events only happen within the sphere of the present moment: that would be in your abstraction, the black horizontal line.

But the black line has a very peculiar property:
since no interaction can happen in zero time, no interaction can happen between the elements of the black line. The black line is a "dead body", meaning that there can be no direct bindings beween its elements.

[IM Egdall]

owl, on 27 October 2011 - 06:15 PM, said:

As I said:

As a psychologist having studied the physiology of perception, I well know that, even with an event happening right in front of our faces, "it takes time" for a visual image of 'what IS happening' to reach the visual cortex and be "experienced" as "now happening."
In that sense, I agree. Our experience of "now" always has a signal delay factor between the "now happening" event and our "now experiencing" that event.

Same principle holds for longer distances between event and perception of event, but that does not deny that the universal present is now happening everywhere.
My favorite example is that a flare on the Sun happening now will take 8+ minutes to be seen on Earth, but that does not deny that "the present" IS now, simultaneously happening both here and there. This, of course, contradicts relativity's claim that simultaneity is relative to the velocity, etc. of all different frames of reference... (that all "reality" depends on the frames of reference from which events are observed.)

Oy! The fact that it takes 8+ minutes for light from the Sun to reach the Earth does NOT contradict the relativity of simultaneity. Why do you claim it does?

[md65536]

michel123456, on 29 October 2011 - 09:00 AM, said:

But the black line has a very peculiar property:
since no interaction can happen in zero time, no interaction can happen between the elements of the black line. The black line is a "dead body", meaning that there can be no direct bindings beween its elements.

But its elements are simply events. The "no direct binding" simply means there's no (instantaneous) information transfer between events at different places on the black line, which means there can be no causal relations between such events. The "direct binding" is essentially a causal connection. Having a mutual "direct binding" between two events would mean that it's possible to have each event cause the other event, which of course is paradoxical.

It's already been established that the light cone (blue lines) represents the immediately perceived "now", which is also the immediate causative now (providing your "direct binding" between an observer and a distant object).

In SR I think the interpretation would be:
- Nothing can interact instantly (including the 'now' instant) over non-zero distance.
- Any influence an object has on an observer (a "binding"?) involves information from a past state of the object.

In your interpretation it might be:
- There is no immediate causal connection between distant objects. Objects are interactively connected only through past events.





"Binding" is a misleading word because you're really only speaking of information transfer and interaction. Two particles can be connected in other ways, such as through quantum entanglement, and be "bound" in that way to each other at 2 different points on your black line. But there is no possible way to transfer information between the particles at those points. They are connected, but not in the essential way that we're talking about here; they're not causally connected.

[owl]

IM Egdall, on 29 October 2011 - 03:31 PM, said:

Oy! The fact that it takes 8+ minutes for light from the Sun to reach the Earth does NOT contradict the relativity of simultaneity. Why do you claim it does?

I am familiar with the aspect of relativity called the relativity of simultaneity.
From Wikipedia:

Quote

In physics, the relativity of simultaneity is the concept that simultaneity–whether two events occur at the same time–is not absolute, but depends on the observer's reference frame. According to the special theory of relativity, it is impossible to say in an absolute sense whether two events occur at the same time if those events are separated in space.

As an advocate of presentism, I dispute the above. Now IS now, both here and on the Sun, even though they are separated in space. All reality does NOT depend on " the observers framer of reference,"... so presentism also disputes the assertion (Wiki, continued):

Quote

“Events A, B, and C occur in different order depending on the motion of the observer. “

They are observed in different order even though they occursimultaneously.

My comments were in reply to michel123456's 10/26 post:

Quote

But you must know that true present is not observable. What we believe is present is in fact the past.

I said:

Quote

In presentism there are no local boundaries around "now" even though it 'takes time' for one location to "see what's happening now" in another location.

My further comments were responding in agreement with michel that there is always a delay between events happening now and our present perception/experience of those events, whether right in front of our faces or at greater distances.

This post has been edited by owl: 29 October 2011 - 07:03 PM

[IM Egdall]

owl, on 29 October 2011 - 06:57 PM, said:

They are observed in different order even though they occursimultaneously.

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

[michel123456]

md65536, on 29 October 2011 - 06:21 PM, said:

But its elements are simply events. The "no direct binding" simply means there's no (instantaneous) information transfer between events at different places on the black line, which means there can be no causal relations between such events. The "direct binding" is essentially a causal connection. Having a mutual "direct binding" between two events would mean that it's possible to have each event cause the other event, which of course is paradoxical.

It's already been established that the light cone (blue lines) represents the immediately perceived "now", which is also the immediate causative now (providing your "direct binding" between an observer and a distant object).

In SR I think the interpretation would be:
- Nothing can interact instantly (including the 'now' instant) over non-zero distance.
- Any influence an object has on an observer (a "binding"?) involves information from a past state of the object.

In your interpretation it might be:
- There is no immediate causal connection between distant objects. Objects are interactively connected only through past events.





"Binding" is a misleading word because you're really only speaking of information transfer and interaction. Two particles can be connected in other ways, such as through quantum entanglement, and be "bound" in that way to each other at 2 different points on your black line. But there is no possible way to transfer information between the particles at those points. They are connected, but not in the essential way that we're talking about here; they're not causally connected.

Exactly. I agree 100%

[Mystery111]

md65536, on 27 October 2011 - 04:52 PM, said:

That line in 2D is a hyperplane in 4D, not a sphere.

Do you wish to continue being pedantic, or are you interested in a serious discussion?

[owl]

IM Egdall, on 29 October 2011 - 07:30 PM, said:

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]

owl, on 1 November 2011 - 06:47 PM, said:

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]

IM Egdall, on 1 November 2011 - 08:10 PM, said:

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]

IM Egdall, on 1 November 2011 - 08:10 PM, said:

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]

MigL, on 2 November 2011 - 07:11 PM, said:

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

http://en.wikipedia....ophy_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]

swansont, on 4 November 2011 - 09:23 AM, said:

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

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]

owl, on 4 November 2011 - 05:43 PM, said:

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".

owl, on 4 November 2011 - 05:43 PM, said:

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...

This post has been edited by PeterJ: 5 November 2011 - 12:32 PM