The Block Universe and The Flow of Time

Discussions on classical and modern physics, quantum mechanics, particle physics, thermodynamics, general and special relativity, etc.

Re: The Block Universe and The Flow of Time

Postby davidm on May 18th, 2020, 10:54 am 

The tenses of time, past, present, and future, are relative to the observer and not to a universal time.


Right, I agree! Presentism says that they are relative to a universal time! What do you think I have been arguing for, in this thread? That is what this thought experiment shows — no universal time, no objectively agreed upon Now. This supports eternalism but not presentism.

his example shows the existence of events does not depend on human awareness.
There is an abundance of evidence of events occurring before human existence. We are seeing images of those events today, but the image is not the event.


I agree with the above, and have explicitly stated so. What has this got to do with anything?
Further reading here.

From the above:
Presentism is the metaphysical view that “only presently existing things exist” (Hinchliff, 2000, p.S576). This view is really only coherent if we assume that space and time are Newtonian in character. As soon as we adopt Einstein’s Theory of Special Relativity and move to a relativistic spacetime, presentism faces some serious challenges. In this paper, I will briefly outline the special theory and its important consequence for presentist metaphysics. From there, I will address some of the specific problems that this consequence creates for presentism, as well as some of the proposed solutions to these problems. Ultimately, though, I believe it will be impossible for us to coherently adopt both the physical theory of special relativity and the metaphysical theory of presentism; and of these two, I believe that it is presentism that we should give up.
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Re: The Block Universe and The Flow of Time

Postby davidm on May 18th, 2020, 11:09 am 

Since rajnz00 doesn’t like to read anything, Here is the Cliff Notes version, from Wikipedia via Science Daily
In the philosophy of time, presentism is the belief that neither the future nor the past exists.
The opposite of presentism is 'eternalism', which is a belief in things that are past and things that are yet to come exist eternally.

One other view (that has not been held by very many philosophers) is sometimes called the growing block theory of time, which is a theory that takes the past and present to exist but the future to be nonexistent.

Presentism is compatible with Galilean relativity, in which time is independent of space but is probably incompatible with Lorentzian/Einsteinian relativity.


Bold by me.

I have already discussed the “probably” modifier quoted above upthread. The papers I have linked that rajnz refuses to read discuss this in greater detail.
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Re: The Block Universe and The Flow of Time

Postby phyti on May 18th, 2020, 1:19 pm 

davidm;

[Only addressing this to you because it appears in your post and not assuming you are promoting it. I long ago ignored packaged philosophies and labels/classifications. Human thought prefers simplicity and discovers reality is more complicated!]

SR, however, is completely consistent with eternalism — the eternalist simply notes that infinite planes of simultaneity are infinite different slices of an existent 4D block universe.


[An axis or plane of simultaneity has to be established using light, and only works for inertial frames, and short/local distances. As such they aren't a factor in distant events.
They are part of an ideal, 'what if' world.
There are zillions of distant events, and only a minuscule amount will ever be observed.]

In fact, proponents of this strategy insist, what SR does prohibit is only that any such absolute simultaneity could not be detected in principle and would hence remain empirically completely inaccessible. Thus, SR does not preclude the existence of an absolute, non-empirical S. Since such an S does exist, though undetectably so, there is no problem in identifying the spatially distant events which are co-present with the here-now.


[Universal simultaneity would require a universal time. Experimental evidence shows time varies for inertial frames. SR predicts the same outcome as LET, but without the ether. The ether is therefore redundant.]

[I still see the confusion in the block universe concept as caused by failure to distinguish between an event occurring, resulting in images dispersed throughout space, and an observer detecting and recording those images. The initial occurrence a, and the detection b, define the ends of the photon life line.]

[In the world of individual perception, the past contains events that have been detected, and thus have occurred, the present contains new events being detected and recorded, and the future is unknown. Any statement about the future is conditional. It's based on history and the assumption that nothing new or different from normal will happen.

Regarding his future, a student may respond he will graduate next year. He may drop out of school, die from a drug overdose, etc. All sequences of events are not considered in predictions, and some are unknown. The future is only partly predetermined based on the consistency of the laws that regulate behavoir of the universe, seasons, eclipses, 'Old Faithful', animal migration, etc. That allows humans to exercise free will, and makes them responsible for their actions/decisions.]
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phyti Explained

Postby rajnz00 on May 18th, 2020, 3:10 pm 

An explanation of phyti’s post

Forgive me phyti, what you said was perfectly clear, but this is for those who still may not have got it, and replied to your thread without looking at your diagram.

I have made some changes, Wherever you have written flash2 and Flash1, I have changed to Event2 and Event1 for greater clarity

phyti » May 17th, 2020, 1:09 pm wrote:davidm;
It exists, because a record of it exists at Mary’s eyes in her present. It does not exist, because the light at Amy’s eyes is in Amy’s future, but the presentist says the future does not exist and so the flash at the back of the train for Mary and then somewhat later at Amy’s eyes cannot exist. So it both exists, and does not exist, according to the presentist line of reasoning, even if the presentist does not notice this obvious contradiction.

......
https://app.box.com/s/a8pt8x4wj1i5tl1crtdzwuq51pg8i9a6

Events* 1 and 2 are flashes of light originating at the front and back of the train.

(Event 1 – Flash at the front of the train

Event 2 – Flash at the back of the train)

Events 1 and 2 exist (when they happen), but Amy and Mary are not aware of them ([b]when they happen)[/b].


Amy at the midpoint of the train becomes aware of Event 2 at event 3.


(Event3 is when the light from Event2 reaches her retina)

Mary on the platform, becomes aware of Events 1 and 2 at event 4.


(Event4 is when the light from Events 1 and 2 reach her retina)

Amy becomes aware of Event 1 at event 5.


(Event5 is when the light from Event1 reaches her retina)

This example shows the existence of events does not depend on human awareness.


In general that statement is true, and specifically, in this case, the existence of Events1 and 2 do not depend on the awareness of Amy and Mary of these Events 1 and 2, which occurred later, at events 5, 4 and 3

There is an abundance of evidence of events occurring before human existence.


Events such as supermassive black holes accreting matter to give rise to Quasars. These events occurred, many thousands of millions of years ago, or even earlier, before humans existed

We are seeing images of those events today, but the image is not the event.


Similarly, Events 3, 4 and 5 are images of events 1 and 2, and they are not events 1 and 2.

Thus any claim made that Events 3, 4 and 5, (the times when Amy and Mary become aware of events 1 and 2), are actually events 1 and 2, and thus pose any dilemma to the presentist who says that events 1 and 2 cease to exist after they occur, is False.

*In physics, and in particular relativity, an event is the instantaneous physical situation or occurrence associated with a point in spacetime (that is, a specific place and time). For example, a glass breaking on the floor is an event; it occurs at a unique place and a unique time.[1] Strictly speaking, the notion of an event is an idealization, in the sense that it specifies a definite time and place, whereas any actual event is bound to have a finite extent, both in time and in space.[2][3]

https://en.wikipedia.org/wiki/Event_(relativity)
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Re: Map Quest

Postby Faradave on May 18th, 2020, 11:54 pm 

rajnz00 wrote:Thus any claim made that Events 3, 4 and 5, (the times when Amy and Mary become aware of events 1 and 2), are actually events 1 and 2, and thus pose any dilemma to the presentist who says that events 1 and 2 cease to exist after they occur, is False.
Nice effort! Only I (& possibly bangstrom) made such an assertion. Appreciate the diagram. But spacetime diagrams give a false impression of being Euclidean (all coordinate axes geometrically independent - i.e. truly orthogonal). The fact that it's impossible for anything to move through space without also going to the future proves that space and time are not independent. We can't trust a spacetime map as if it were a Cartesian plane.

Thus, a reminder from a respected author...
"… the best we can do for figures in Minkowski space is to map them onto Euclidean space, as did Mercator with his flat map of the curved surface of the earth. Such maps necessarily distort metric relations and one has to compensate for this distortion." – Rindler p.90

Image

Unless you're willing to accept my Euclidean interval-time coordinates, the only recourse is to follow the math which indicates zero interval separation along any lightlike path.
Or you can ignore me ... lot's of people do...
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Re: The Block Universe and The Flow of Time

Postby Positor on May 19th, 2020, 12:53 am 

I believe that science should take experience as its starting point, and seek to explain that. One may in some cases regard experience as an illusion, but then one needs to explain the 'illusion', so it is preferable to apply Ockham's Razor and regard experience as real in the first place. A dream, a mirage, etc are real experiences.

Now apply that criterion to the present topic. The reality is that we experience/observe lightlike paths to be extended in time and space. So events along such paths are distinct. Any implication that they are not 'really' distinct (i.e. that they are in 'contact' in some higher reality) is unhelpful from an explanatory point of view, although it may be convenient in a mathematical context. If it is argued that two events can be in contact but nevertheless distinct, I would ask how it is possible for two different things to exist at the same point (in any dimensionality).

The comparison with a Mercator projection is a false one, since we do not experience the South Pole as a line; we do not observe distinct events occurring at different points on such a line. By contrast, we do experience a lightlike path as a line, with distinct events along it.

If two events are co-located in 3D space, they remain co-located in lower dimensions (i.e. on a 2D plane or a 1D line). By analogy, events co-located (i.e. in Faradave's 'contact') in 4D spacetime (in which time is equivalent to a fourth spatial dimension) should remain so in lower dimensions; but we know from our 3D experience that they do not.
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Re: Destination Relation

Postby Faradave on May 19th, 2020, 2:03 am 

Positor wrote:we do experience a lightlike path as a line, with distinct events along it.
You experience light but you do not experience lightspeed. Interval contact is speed c-dependent. This is a consequence of time being one of the dimensions, and spacetime being non-Euclidean.

You already now you can't trust your experience of spatial separation. Path contraction with increasing speed brings any far distant destination arbitrarily close. A light quantum takes it all the way at c.

Have you ever experienced a neutrino? Uncountable trillions just passed through you!
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Re: Ghostly Interaction

Postby rajnz00 on May 19th, 2020, 2:45 am 

Faradave » May 19th, 2020, 2:03 am wrote:...Have you ever experienced a neutrino? ...


Not sure. I did have an unexplained pinprick on my finger once.
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Re: Lost in Maps

Postby rajnz00 on May 19th, 2020, 2:57 am 

“Or you can ignore me”

I won’t ignore you, instead, I’ll point out how some basic maths concepts can resolve what might seem to be a complicated problem. You have to have a feel for maths, and be aware of the axioms and postulates of geometry.

Faradave » May 18th, 2020, 11:54 pm wrote:
rajnz00 wrote:Thus any claim made that Events 3, 4 and 5, (the times when Amy and Mary become aware of events 1 and 2), are actually events 1 and 2, and thus pose any dilemma to the presentist who says that events 1 and 2 cease to exist after they occur, is False.


Nice effort! Only I (& possibly bangstrom) made such an assertion. Appreciate the diagram. But spacetime diagrams give a false impression of being Euclidean (all coordinate axes geometrically independent - i.e. truly orthogonal). The fact that it's impossible for anything to move through space without also going to the future proves that space and time are not independent. We can't trust a spacetime map as if it were a Cartesian plane.

Thus, a reminder from a respected author...
"… the best we can do for figures in Minkowski space is to map them onto Euclidean space, as did Mercator with his flat map of the curved surface of the earth. Such maps necessarily distort metric relations and one has to compensate for this distortion." – Rindler p.90

No matter how much we compensate, we know that the causal order is maintained.

Thus, no matter which frame of reference an observer may be, their observational events Eo1 and Eo2, of E1 and E2, will always be later than E1 and E2, thus my analysis and conclusions are unassailable.
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Re: On the ball

Postby Faradave on May 19th, 2020, 10:41 am 

rajnz00 wrote: the causal order is maintained
I treat time as fundamentally unidirectional. This is why a given event has incoming (from the past) and outgoing (to the future) light cones.
Image

By classical analogy, when a cue ball hits a stationary 8-ball, they make contact which is mutual, yet energy, momentum and information flow forward in time as the 8-ball takes off in space.

Contact of any sort, though mutual (each "touches" the other) always maintains a unidirectional component. An energized electron never emits to the past. Causality is safe.
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Re: The Block Universe and The Flow of Time

Postby phyti on May 19th, 2020, 2:33 pm 

As long as 'time' is considered an independent entity, and human perception is ignored, there will be confusion.
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Re: The Block Universe and The Flow of Time

Postby rajnz00 on May 19th, 2020, 3:30 pm 

The Block Universe – Refuting a Common Argument

I came across another refutation that the Block Universe is mandated by SR or that presentism is ruled out.

I say another argument because, the first argument, (other than mine) that I became aware of, was that of Sabine Hossenfelder, in her blog The Block Universe, in which she unerringly pointed out that Petkov’s paper, which she said she disliked and was in the process of chucking into the rubbish bin, was based his presumptions of existence, whereas SR had nothing to say about existence.

She also said that the Block Universe, was no more than a belief of hers that she personally found plausible and she didn’t think it followed from SR.

The other refutation is from one Peter Donis, The Block Universe – Refuting a Common Argument
https://www.physicsforums.com/insights/ ... -argument/

The “block universe” interpretation of SR has come up repeatedly in threads here on PF. Rather than link to them, I want to summarize a common argument that is made for the “block universe” being necessary, and then summarize the arguments I made in those threads to show why the common argument is not valid. The common argument for the “block universe” comes in several forms, all logically equivalent; the one I’ll use here is the “Andromeda paradox”:
....
we can summarize the Andromeda paradox argument as follows: (1) Relativity of simultaneity + all observers’ 3D worlds are real at every event = block universe (I’ve used the word “real” here because that’s the word that block universe proponents often use; but note that it’s really shorthand for “events to the past of any observer’s 3D world at any event are fixed and certain”.)
….
Most block universe proponents spend no time at all on the second premise, apparently because they think it’s so obvious that it doesn’t need justification or argument.

However, that premise, often unstated and assumed, is patently false. (My words not his)
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Re: Conventional Wisdom

Postby rajnz00 on May 20th, 2020, 3:07 pm 

“Conventional wisdom” are ideas so accepted they go unquestioned.

Conventional wisdom is sometimes spectacularly wrong. For example, once the conventional wisdom was that the Earth was flat, and that the Earth was the centre of the Universe.

Conventional wisdom is held for two main reasons, either that there is compelling evidence for it within everyone’s experience or that most scholars adhere to that view.

Conventional wisdom, or any wisdom, needs a further step from evidence to general acceptance, and that is the interpretation of that evidence.

When the Earth was flat, the evidence was, it looked flat, and the interpretation straight forward, it was flat. Neither the evidence, nor the interpretation was spectacularly wrong, on the scale of human observance from the average height of the eye. However, this yielded to more evidence and better interpretation. Ships masts appearing before the base etc.

The current conventional wisdom of “the relativity of simultaneity”, (shorthand for what simultaneity implies in Special Relativity or what it is supposed to derive, again by “conventional wisdom”), is that, it in and of itself implies the Block Universe and rules out presentism.

This conventional wisdom relies entirely upon the interpretation of Special Relativity, and specifically of the first postulate “In electromagnetism as well as in mechanics, phenomena have no properties corresponding to the concept of absolute rest.” And even more specifically the counterintuitive derivation and evidence that events that appear simultaneous to one observer will not appear simultaneous to another observer, moving at a constant speed with respect to him.

On a very fundamental level, this is all that SR has to say about simultaneity. A person looking at this and not being indoctrinated with anything else would say, okay so there is nothing special about simultaneity, nothing intrinsic about it.

But because it is so counterintuitive, scholars have further derived results, in convoluted ways, that to my mind, are spectacularly wrong. These interpretations, in fact, go against the very fundamental lesson of SR, that there is nothing special about simultaneity, and to say that two events spaced distantly apart are simultaneous is essentially meaningless. They have derived meaning, from something that is meaningless.

They have indulged in the logical equivalent of the Fleamaster, who pulled off the legs of his jumping flea and then concluded that the flea was deaf because he could no longer obey his command to jump. They have interpreted the indisputable evidence, that simultaneous events are not intrinsically simultaneous, to derive spectacularly wrong conclusions.

So indoctrinated are these followers of the conventional wisdom that they refuse to look at straightforward and uncomplicated refutations of their conclusions, refuse to directly address them, and instead fall back on references to authorities with a voluminous treatise that support their claims, and demand that we wade through them and discover the error in their champion’s thesis.

A simpler way of dealing with it is, like Sabine Hossenfelder, take the thesis and toss it into the trash can.
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Re: The Block Universe and The Flow of Time

Postby curiosity on May 20th, 2020, 11:44 pm 

The fact that it's impossible for anything to move through space without also going to the future, proves that space and time are not independent.

Although I agree and believe that you are beyond any shadow of doubt correct... I will wish you the best of luck explaining that concept here, as there seems to be a general consensus on this this site that although it is impossible to travel backwards through time, it "is" possible to travel backward through space...

To my mind, being able to revisit a physical location here on earth, or for that matter anywhere in our solar system, doesnt mean you have travelled backwards through space It means you have progressed (kept going forward through space, but in the opposite direction to the one you had previously been heading in. (unless of course you cicumnavigate the globe.) But... when you reach any previously visited co moving location, that location is not actually in either the same spatial or temporal location, it was in when you last visited it, it has actually progressed through both space and time due to the ever onward motion of our planet through "space" and its conjoined twin "time."
But then... What did Einstein and Minkowski know, when they said that space and time can no longer be considered seperate?

How can such a simple concept be so difficult to explain?
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Re: The Block Universe and The Flow of Time

Postby rajnz00 on May 21st, 2020, 2:55 am 

curiosity » May 20th, 2020, 11:44 pm wrote:
The fact that it's impossible for anything to move through space without also going to the future, proves that space and time are not independent.

Although I agree and believe that you are beyond any shadow of doubt correct...

I believe that he, [Faradave], is incorrect. I believe that is also impossible in classical Newtonian mechanics, where time moves relentlessly forward, thus it does not prove that space and time are not independent.

I will wish you the best of luck explaining that concept here, as there seems to be a general consensus on this this site that although it is impossible to travel backwards through time, it "is" possible to travel backward through space...

Poor Faradave, a voice crying in the wilderness, a prophet without honour in his own land.

To my mind, being able to revisit a physical location here on earth, or for that matter anywhere in our solar system, doesnt mean you have travelled backwards through space It means you have progressed (kept going forward through space, but in the opposite direction to the one you had previously been heading in. (unless of course you cicumnavigate the globe.) But... when you reach any previously visited co moving location, that location is not actually in either the same spatial or temporal location, it was in when you last visited it, it has actually progressed through both space and time due to the ever onward motion of our planet through "space" and its conjoined twin "time."

All that you have described is perfectly described by Newtonian mechanics also, where the twins are healthy and far from conjoined.

But then... What did Einstein and Minkowski know, when they said that space and time can no longer be considered seperate?

I believe it was Minkowski who said that. As bangstrom put it “The union of space and time means there is an element of motion through time included in any motion through space. Motion through space is like moving through time zones where you need to set your clock back by one second for every 300,000 km of distance traveled.
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Re: Great Pains to Explain

Postby Faradave on May 21st, 2020, 11:23 am 

rajnz00 wrote:I believe that is also impossible in classical Newtonian mechanics, where time moves relentlessly forward, thus it does not prove that space and time are not independent.

In view of speed limit c, even Newton would have to agree that time and space are not independent. In a Cartesian XY-plane, the X- and Y- coordinates are geometrically independent because it is possible to have a displacement on either axis independent (i.e. without entailing a displacement) on the other.

By contrast, a diagonal line is dependent on both coordinates because displacement on the diagonal always entails displacement on both coordinate axes. Speed limit c means one cannot move through space without also moving through time. Space and time are not geometrically independent.

A bright reader might exclaim, "But being at rest (with respect to the cosmos), one can move through time without moving through space. They are independent!" That can be explained with a curved-space, radial-time model. A curve is not independent of flat coordinates any more than a diagonal line. However, at any given point in space a radial timeline would be normal (orthogonal with its tangent) to space. One could move through time without moving through space but because instantaneous motion is impossible (by limit c), one cannot move through space without moving through time. Q.E.D. (Whoa! Was that a proof?!)

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Re: Great Pains to Explain

Postby rajnz00 on May 21st, 2020, 2:24 pm 

Faradave wrote:Q.E.D. (Whoa! Was that a proof?!)


Not sure. didn't read. What was that supposed to be a proof of?

Remember your claim?

The fact that it's impossible for anything to move through space without also going to the future, proves that space and time are not independent.

Faradave » May 21st, 2020, 11:23 am wrote:
rajnz00 wrote:I believe that is also impossible in classical Newtonian mechanics, where time moves relentlessly forward, thus it does not prove that space and time are not independent.


You have to prove that you can move though space in Newtonian mechanics without moving into the future.

The relevant equation is: s = ut + ½ at2

This is Newton, where space and time are independent

Remember that time ticks away independently in Newtonian mechanics. So if you move through space, you go forward in time.

So the mere fact that you cannot move through space without going forward in time does not prove space and time are not independent.

PS where did you learn basic maths? You can describe the angle of a line by its length? Amazing! PS don’t bother with the proof. Just publish it.
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Re: Can you hear me now?

Postby Faradave on May 21st, 2020, 3:28 pm 

rajnz00 wrote:Not sure. didn't read. What was that supposed to be a proof of?
I just sent by smoke signals. Hope that helps.

rajnz00 wrote:You have to prove that you can move though space in Newtonian mechanics without moving into the future.
No! That would support their independence. Wait, ... I'll go yell that out my front door.

rajnz00 wrote:if you move through space, you go forward in time.
That suggests dependence

rajnz00 wrote:You can describe the angle of a line by its length?
I never said exactly that. Here, I wrote that the slope (or angle) can be expressed "in terms of its length", which I demonstrated.
e.g. sinθ = opposite/hypotenuse, where hypotenuse is the magnitude (typically length) of the diagonal. So, θ = arcsin(opposite/hypotenuse).
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Re: Can you hear me now?

Postby rajnz00 on May 21st, 2020, 3:48 pm 

Faradave » May 21st, 2020, 3:28 pm wrote:
rajnz00 wrote:You can describe the angle of a line by its length?

I never said exactly that.


I don't think you know what exactly is

I wrote that the slope (or angle) can be expressed "in terms of its length", which I demonstrated.
e.g. sinθ = opposite/hypotenuse, where hypotenuse is the magnitude (typically length) of the diagonal.

Go back to primary school. Find out what sinθ is.

No time for the rest of your rubbish
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Re: Termination Elation

Postby Faradave on May 21st, 2020, 11:01 pm 

Faradave wrote:sinθ = opposite/hypotenuse, where hypotenuse is the magnitude (typically length) of the diagonal


rajnz00 wrote:Go back to primary school. Find out what sinθ is.

I leave it to anyone to check my reference. Sometimes I do get mixed up but I don't see it here.
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rajnz00 wrote:No time for the rest of your rubbish
Good! You've finally taken my advice.
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Re: The Block Universe and The Flow of Time

Postby BurtJordaan on May 22nd, 2020, 12:28 am 

Faradave wrote:I wrote that the slope (or angle) can be expressed "in terms of its length", which I demonstrated.
e.g. sinθ = opposite/hypotenuse, where hypotenuse is the magnitude (typically length) of the diagonal.

I think rajnz00 had it against your sloppy statement.
Slope is obviously tan(θ), which is opposite/adjacent. And it is not expressed in terms of a length, but rather a ratio.

Sloppy writing occurs very often on forums, and it would benefit everybody if pointed out and corrected in an amicable way.
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Re: Confusion Illusion

Postby Faradave on May 22nd, 2020, 1:25 am 

If that's true, I think rajnz00 has a sloppy way of saying it.
rajnz00 wrote:Go back to primary school. Find out what sinθ is.

Each side of a triangle carries as much information about its angles as any other. As you note, we're all taught slope = rise/run. But the magnitudes of the legs of a right triangle may not always be available. It's nice to be aware of alternatives. The hypotenuse is certainly one of them.
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Re: Rubbish removal

Postby rajnz00 on May 22nd, 2020, 1:42 am 

Faradave » May 21st, 2020, 11:01 pm wrote:Sometimes I do get mixed up but I don't see it here.

It took you 8 hours of painful searching and checking before you could come up with that? Well I’m glad you did, because your elementary knowledge of maths is woefully lacking, so keep it up.

I was rushing off to work and as BurtJordaan pointed out I meant slope of course. Every school kid who has taken maths knows you use tan to find a slope, and “that the slope (or angle) can be expressed "in terms of its length"” is completely senseless! The slope is a ratio.

No one uses sine to find the slope. You would have to be particularly brilliant to do that, because you have to first calculate the hypotenuse or derive it from.. guess what? tan!

rajnz00 wrote:No time for the rest of your rubbish


No time, as I was rushing off to work. My weekend starts now, so I’ll spare a little time to deal with the rest of your rubbish. I have reserved this weekend for rubbish clearing anyway, so I’ll start with you.

I could be parsimonious and sum up your 25-word statement,
"The fact that it's impossible for anything to move through space without also going to the future, proves that space and time are not independent."
with one elegant, succinct and sufficient word – Rubbish.

But of course this will probably not be immediately obvious to you, as it was to me, so I will wade through with a painfully detailed explanation, in my next post, so that you may join me in labelling your statement in like fashion, and clear it from your head. Good time for rubbish removal
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Re: What er yer smokin?

Postby rajnz00 on May 22nd, 2020, 2:19 am 

Faradave » May 21st, 2020, 3:28 pm wrote:
rajnz00 wrote:I just sent by smoke signals.


I am concerned for you. Smoke inhalation is bad, specially if you are burning marijuana leaves.

rajnz00 wrote:You have to prove that you can move though space in Newtonian mechanics without moving into the future.

No! That would support their independence.

It is as I feared. The smoke has got to you.

If you can't prove in Newtonian mechanics that you can move through space without moving forward in time, them your statement is wrong.

Wait, ... I'll go yell that out my front door.


Did the dogs in your neighbourhood respond to your yelling? Please take it easy, this is not a contest, and they have evolution on their side. Take a few deep breaths, that will help calm your nerves.

rajnz00 wrote:if you move through space, you go forward in time.

That suggests dependence

I thought I'd get that one past you, but you are quite bright. Maybe I shouldn't have given you the equation.

Yes you are right. There is dependence between moving through space and time. Even Newton couldn't do without that.

I wonder if you even realise what you are saying? I wouldn't be surprised if you didn't. So let me spend a little time in explaining what you are saying. (Though really you should be spending the time doing that. And if you did, would probably realise the absurdity of what you are saying)

The fact that it's impossible for anything to move through space without also going to the future, proves that space and time are not independent.


In Newtonian mechanics Space and Time are independent. But you cannot move through space without going forward in time.

Thus the fact that it's impossible to move through space without going to the future does NOT prove that space and time are not independent.
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Re: The Block Universe and The Flow of Time

Postby phyti on May 22nd, 2020, 10:58 am 

Wikipedia: Eternalism, the present.

In this way time is said to pass, with a distinct present moment "moving" forward into the future and leaving the past behind.


[The writer is using someone's preconceived notions. 'Time' is not a 'place'. Events don't move.]

Both ends of the bar pass through the ring simultaneously in the rest frame of the ring (left), but the ends of the bar pass one after the other in the rest frame of the bar (right).


[Incorrect, by using the same ref. frame for both cases, contradicting postulate 1.]

[The remainder of the article is just a continuous stream of authority figures and philosophical labels.]
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Re: The Block Universe and The Flow of Time

Postby davidm on May 22nd, 2020, 11:05 am 

The guy quoted upthread trying to defeat the eternalist interpretation of the Andromeda Paradox appears to be arguing for a thesis called cone presentism, which is discussed here. The author of this paper relates the work of Mark Hinchcliff, who tries to reform presentism to make it compatible with SR in three ways: Point presentism, cone presentism, and surface presentism, the thesis, which I already alluded to earlier in quoting from a different paper, that SR does not rule out a privileged, absolute at-rest frame — it only rules out that this frame can ever be found within SR itself. So unless SR and GR are superseded by, say, a quantum theory of gravity that restores a privileged frame, then the third argument, as I noted, has no scientific content and amounts to an article of faith, like religious belief.

Note that Hinchcliff understands that standard presentism is in direct conflict with SR, and so must be either modified (point or cone presentism), or it must be held metaphysically superior to SR (no way to detect privileged frame from within SR; i.e., not science) or it must be scrapped. He admits that the standard view of presentism — that there is a single universal space in which the only objects that exist are simultaneous for all observers — is applicable only to a Newtonian conception of space and time, and not to SR. He proposes a reformulation of presentism to accommodate space and time together (Minkowski spacetime) rather than space and time separately (Newtonian space and time). Fair enough. Does he succeed?

Well, no, not in my opinion, and not in the opinion of the author of the paper linked above. Those interested in pursuing this discussion can read the paper or not as they see fit; I have a sneaking suspicion it will remain unread.

Before commenting directly on the paper, I want to emphasize the following: rajnz00 is NOT arguing the same way as Sabine. Not even close. I’ve pointed this out before, but it bears repeating.

Sabine is not a presentist. She is an eternalist. She thinks we live in a block universe. So if Raj were arguing the same way as Sabine, then he, too, would be an eternalist. But he says he is not. So his argument is not the same as Sabine’s, QED.

Sabine’s only point of disagreement with Petkov, who like her is an eternalist, is that she does not think, unlike Petkov, that SR, by itself, entails a block universe. She is correct — one can adopt the metaphysical, unscientific view, noted above in this post and also further upthread, that SR entails only that we cannot detect a privileged frame from within SR, not that there isn’t one. Again, this is faith-based metaphysics and has nothing to do with science.

I reiterate again that since rajnz00 has explicitly rejected standard presentism when I showed it to him, it must be that he is either a point presentist, a cone presentist, or a surface (metaphysical) presentist who rejects SR for the reason given above. If he is something else, I don’t know what it is. I suspect he doesn’t either, because I don’t think he has ever unpacked the metaphysical implications of what he believes. I’ll comment on point and cone presentism in a later post.

Hinchcliff’s papers are online, but so far none I have found are freely available.
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Re: The Block Universe and The Flow of Time

Postby BurtJordaan on May 22nd, 2020, 11:11 am 

phyti » 22 May 2020, 16:58 wrote:Wikipedia: Eternalism, the present.
Both ends of the bar pass through the ring simultaneously in the rest frame of the ring (left), but the ends of the bar pass one after the other in the rest frame of the bar (right).

[Incorrect, by using the same ref. frame for both cases, contradicting postulate 1.]

If you wrote the statement in the [brackets], it is you that are incorrect - the quoted piece is standard SR.

The article is about philosophy of science though, not science per se.
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Re: Wheat from the Chaff

Postby Faradave on May 22nd, 2020, 2:18 pm 

rajnz00 wrote:In Newtonian mechanics Space and Time are independent. But you cannot move through space without going forward in time.
That's a contradiction. Newton had no understanding of invariant speed limit c, many people still don't (...even some smart ones)!

rajnz00 wrote:Yes you are right. There is dependence between moving through space and time.
That's correct. Good!

"Generalized coordinates are usually selected to provide the minimum number of independent coordinates that define the configuration of a system, ..."

It's a mistake to consider space and time as independent Cartesian coordinates precisely because nothing moves through space independent of moving through time. That's why spacetime coordinates are described as "non-Euclidean".

P.S. As I've indicated before, job has priority over replies as far as I'm concerned. I don't mind waiting (even several days) to be insulted (really).
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Re: Wheat from the Chaff

Postby rajnz00 on May 22nd, 2020, 8:13 pm 

Faradave » May 22nd, 2020, 2:18 pm wrote:
rajnz00 wrote:In Newtonian mechanics Space and Time are independent. But you cannot move through space without going forward in time.
..... Newton had no understanding of invariant speed limit c, many people still don't (...even some smart ones)!


That only proves that you are smarter than Newton, but sadly not that Space and Time are not independent, by the mere fact that when you travel through space you go forward in time.

When you travelled through space, from your couch to the front door to yell outside it, it probably took you a few seconds, made you few seconds older. Did you clap your hand to your forehead and say - Aha, this proves space and time are not independent?

rajnz00 wrote:Yes you are right. There is dependence between moving through space and time.


There is a difference in moving through space and Space itself. Newton's equation describes the distance travelled while moving through space and the time taken to move this distance.

Space itself and Time itself are independent in Newtonian mechanics.

When you travel to another town you travel forward in time. You do not arrive before you started. Similarly, when a rocket is fired to the Moon or Mars, it arrives after it is launched.

Hope that helps
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Re: Instant Results

Postby Faradave on May 22nd, 2020, 11:53 pm 

There is a difference in moving through space and Space itself.
I understand what your saying. A simultaneous space can be defined for any inertial observer at a given moment. By why can't that observer move through it (instantly)? Because time and space are not independent.

Newton had no idea of a universal speed limit. Through most of his work in optics light was thought to transmit instantly. If instantaneous motion were possible then space and time would be independent. But it's not. I don't have anything more to say on this. Have a good weekend.
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