If you think of a time line with a duration of time (instead of an instant) moving with the arrow of time then the backward propagation only exists in the duration....moving backward. — Mark Nyquist

Ok, this makes more sense. That is known as two dimensional time, I call it the breadth of the present. There is no need to call it a backward flow though, only a requirement to understand that somethings move from future into past before other things. "Before" here is determined by the traditional timeline. Activity occurs at the present which divides future from past. Some aspects of reality would cross the divide, therefore be active, prior to others, and would have a special form of causal power because of this.

Try this,

Take a sheet of lined paper and write t1 to t10 down the left side.

Draw a box next to t1. It represents a duration of physical matter during the T1 duration

Draw a box next to t2 shifted to the right by say a third the duration of t1. Same size.

And so on down the page.

Think of the boxes as matter progressing through time in 3D. — Mark Nyquist

Do you men to place the boxes as overlapping?

The time intervals are clock times. Very small.
The point is duration t3 can have an effect on t1.

The point is duration t3 can have an effect on t1. — Mark Nyquist

How, unless the boxes overlap?

Ok. Overlap the boxes.

Why do you not answer my question: By what means do you sever space and time? — ucarr

I answered it. You just missed it.
... Or maybe you weren't there. :grin:

This back propagation idea is speculative.
Another possibility is if some future branching exists then you also have a mechanism for spooky action at a distance. Quantum entanglement.

So I'm looking at it until someone gives me a reason not to.

It may have come up here before but I'm not finding it.

Why do you not answer my question: By what means do you sever space and time? — ucarr

I answered it. You just missed it.
... Or maybe you weren't there. :grin: — Alkis Piskas

Although Minkowski writes about time without gravity in special relativity, in general relativity time is tied to mass through gravity.

In the everyday world, the movement of massive objects is tied to time.

Again, all this has to do with the dilation of time. How mass affects time. Nothing to do with what I maintained.

...time is irrelevant to matter and vice versa. — Alkis Piskas

Is there anything time is connected to?

Actually the concept of "matter" was constructed by Aristotle to account for the reality of temporal continuity. What persists unchanged, as time passes, despite changes to a thing's form, is the thing's matter. So matter provides the basis for a thing's extension in time.

...time is irrelevant to matter and vice versa.
— Alkis Piskas
Is there anything time is connected to? — ucarr

Don't quote a stetement cut off from its immediate context. It's a very bad and unacceptable habit, ucarr. You must quote the whole idea, thought or argument. I quote it for you:
"Time has no mass, neither does it occupy space. So time is irrelevant to matter and vice versa."
The statement that you quoted cut off from the whole, on purpose, is relevant and in respect to the previous one. It does not mean that there is no connection between mass and time.
In doing so, you show that you ignore, also on purpose, the first statement, which is the main and most important idea here.

I have enough with all that, ucarr. You are a bad interlocutor. Please don't bother me again.

Well, this is debetable. Anyway, it refers to a specific theory: the energy wave theory, where it is considered a medium that allows the transfer of energy of its components. But I believe it is used for descriptive purposes, as I mentioned.
In reality, space and time cannot be perceived as physical things, as matter and enery can.
Neither can space or time produce change or movement. Rather the opposite: change and movement produce the notion of space and time. — Alkis Piskas

Spacetime can affect the motion of objects and light. Massive objects can change the curvature of spacetime as well.

Spacetime can affect the motion of objects and light. Massive objects can change the curvature of spacetime as well. — MoK

Spacetime doesn't really exist. It isn't real, in the way matter and energy are. It is theory. It's a mathematical model.
"Spacetime is any mathematical model that fuses the three dimensions of space and the one dimension of time into a single four-dimensional continuum. Spacetime diagrams are useful in visualizing and understanding relativistic effects such as how different observers perceive where and when events occur." (Wikipedia)

Logic does have its limits.

And sometimes those limits are determined by the way in which we choose to assemble the language.

For example, one could just as well say: time is the measure of change rather than a pre-requisite for it. There would be no time in the absence of change. Time is not in the nothing anymore than time is in the something.

And of course we would have a different set of logical implications.

Spacetime doesn't really exist. It isn't real, in the way matter and energy are. It is theory. It's a mathematical model.
"Spacetime is any mathematical model that fuses the three dimensions of space and the one dimension of time into a single four-dimensional continuum. Spacetime diagrams are useful in visualizing and understanding relativistic effects such as how different observers perceive where and when events occur." (Wikipedia) — Alkis Piskas

Unfortunately, the wiki references in some cases are not good enough or may be misleading. You will enjoy this article if you want to get involved in the debate of whether spacetime is a substance or not. I am a physicist and cannot understand the article well since it is very technical.

And sometimes those limits are determined by the way in which we choose to assemble the language.

For example, one could just as well say: time is the measure of change rather than a pre-requisite for it. There would be no time in the absence of change. Time is not in the nothing anymore than time is in the something.

And of course we would have a different set of logical implications. — Arne

Time and space are twisted and are parts of a single manifold called spacetime. This means that you have time if you have space.

...time is irrelevant to matter and vice versa. — Alkis Piskas_ucarr

Is there anything time is connected to? — ucarr

Don't quote a stetement cut off from its immediate context. It's a very bad and unacceptable habit, ucarr. — Alkis Piskas

I have enough with all that, ucarr. You are a bad interlocutor. Please don't bother me again. — Alkis Piskas

You accuse me of intentionally quoting you out of context for the purpose of fatally distorting your intended meaning, all of this towards setting up a misrepresentation of you as a straw man easy to defeat in debate.

Of course I respect your demand I no longer attempt to dialogue with you. However, I have a right to rebut your accusation. My defense herein is for the public record; it's not an example of my ignorance of your demand.

Let's begin by noting the ellipsis: the three dots at the beginning of my abridged quotation of your words. An ellipsis is a public announcement to all readers the quotation is abridged. It's a notification to everyone words have been omitted from the quotation. When someone seeks to quote another person out of context for the purpose of distortion and misrepresentation of that person, including an ellipsis contradicts that purpose.

Moreover, here at TPF, what value is gained by misquoting someone when the public record makes it easy for everyone to examine the original statement? Since it's easy for the supposedly misquoted person to copy and repost their original statement and then juxtapose it to the abridged version for public inspection -- something you've done here without causing me a smidgen of difficulty in mounting my defense -- it's clear only a fool would bother with making the attempt.

Actually the concept of "matter" was constructed by Aristotle to account for the reality of temporal continuity. What persists unchanged, as time passes, despite changes to a thing's form, is the thing's matter. So matter provides the basis for a thing's extension in time. — Metaphysician Undercover

I presume the above quote from Metaphysician Undercover is the cause of your contempt over my abridgment of your quote. Indeed, I think it a strong rebuttal to your statement.

The question here is whether Metaphysician Undercover's rebuttal loses strength when applied to the complete version of your statement:

Time has no mass, neither does it occupy space. So time is irrelevant to matter and vice versa. — Alkis Piskas

In this particular conversation, I haven't been disputing your claim time possesses neither mass nor material dimensions.

I've underlined your conjunction in the second sentence of your statement. I'm presuming you're arguing the conjunction puts restrictions upon how your claim should be interpreted. I'm further presuming you believe Metaphysician Undercover's rebuttal doesn't apply to your claim without these restrictions.

In my opinion, separating time from mass and material dimensions is central to your claim of its irrelevance to same.

...What persists unchanged, as time passes, despite changes to a thing's form, is the thing's matter. So matter provides the basis for a thing's extension in time. — Metaphysician Undercover

According to my interpretation, Metaphysician Undercover's quotation of Aristotle carries the message time, mass and matter are married, the exact opposite of your claim.

As I see it, the conclusion of your claim -- as based upon the premise time has no connection to matter -- that time is irrelevant to matter and vice versa, still gets authoritatively contradicted by Metaphysician Undercover.

Replacing the words I removed merely shows more explicitly what Metaphysician Undercover's quote contradicts. The added words do not give your claim defense against the rebuttal. On the contrary, they make the truth of the rebuttal more apparent.

Let me further say this: A thing's extension in time ⟺ Time's extension in a thing.

All of this is to argue my abridgment of your statement -- regardless of my intentions -- does not weaken it.

Unfortunately, the wiki references in some cases are not good enough or may be misleading. You will enjoy this article if you want to get involved in the debate of whether spacetime is a substance or not. I am a physicist and cannot understand the article well since it is very technical. — MoK

My position on the subject is certainly not based in any way on what Wikipedia says. I just brought up this ref for the occasion. It was just handy ...

This is a subject I have discussed a lot and in lengths, in here and elsewhere, where I have described the non-physical nature --in fact, the non-reality-- of time. I could do it with you too, but it will take too long.

Now, I gave you and short example. You give me a huuuge article to study! (You are not the only one who does that.) So, thanks but no thanks. :smile:

Here what I came up with to explain back propagation through time.

t0 to t3
t1 to t4
t2 to t5
t3 to t6
t4 to t7
t5 to t8
t6 to t9
t7 to t10
t8 to t11
t9 to t12

These are ranges of clock time at quantum scale.
A range of time has physical events that coexist in the time range.

A physical event at t3 could effect t0 because they coexist.

A physical event at t12 can not directly effect t0.

However, if a signal can form a chain of physical matter that can transmit a signal, it may be possible to back propagate between t12 and t0.

In theory, a signal back propagating in matter could, as time progressed from the big bang, have been back propagating from a future state to the big bang era.

So retro causality could be involved in the big bang era.

A signal needs a physical carrier so the carrier would be things that exist at the quantum scale.

If energy is involved, that too could propagate opposite the arrow of time.

I suspect that is the case given the logic of the problem.

Time and space are twisted and are parts of a single manifold called spacetime. This means that you have time if you have space. — MoK

Thank you.

I already know that.

And nothing I said is inconsistent with it.

You mentioned that time does not exist if change does not exist.

That a thing, time in this case, does not occupy space, does not imply that it is not related to space. So if time does not occupy space, as stated, this does not mean that time is irrelevant to space. Nor can we say that time is irrelevant to things which occupy space, massive things, which the concept of "matter" applies to. So the premises required to conclude that time is irrelevant to matter, are not there.

:up: :100:

My thanks to you for this persuasive argument.

yes I did.

But time exists if space exists independent of whether change exists or not.

But time exists if space exists independent of whether change exists or not. — MoK

you are putting the cart before the horse. The greatest change in the history of the universe is the Big Bang. There would be no space/time without the Big Bang. Ergo, there would be no space/time without change.