Is there such a thing as at rest ?

[JesseM]

Fundamentally, what is your justification for this symbol "time" referring to a "dimension"? An equation can have as many parameters in it as we want, they don't equal dimensions.

I don't know what significance you are imparting to the word "dimension", but for me any parameter can in fact be treated as a dimension in the phase space of a system.

This is not an issue that can be resolved mathematically.

What is not an issue that can be resolved mathematically?

Mathematics deals with useful descriptive models. Time is a useful parameter to humans so we put it in our equations.

And would you not say the same thing about spatial dimensions? If not, why not?

The idea of eternalism is not that "time is a dimension", but that all events throughout space and time have the same ontological status, that there is no unique subset of events that are specially marked out as being in the objective "present". Mathematically you can model the relationship between these events in terms of their relative positions in a 4D pseudo-Riemann manifold, but as you say this is a descriptive model, and this model could be used by a presentist too. The point is that if we can make all the correct predictions about physical events using a model that does not include any notion of objective truths about simultaneity, then philosophically there is no irrefutable argument for believing there must be any absolute truth about simultaneity, even though you are still free to take the presentist position which says there is. Do you think this is wrong? If so, please present whatever irrefutable philosophical argument for absolute simultaneity that you think you have.

 

[Mentz114]

altonhare:

Fundamentally, what is your justification for this symbol "time" referring to a "dimension"? An equation can have as many parameters in it as we want, they don't equal dimensions. This is not an issue that can be resolved mathematically. Mathematics deals with useful descriptive models. Time is a useful parameter to humans so we put it in our equations. When you reduce this down to essential language "time" is no more than relative motion and is, in fact, unnecessary though convenient.

(my emphasis)
Time is essential in doing physics, just as the passage of time is an inescapable fact of existence. This is a physics forum. You are talking something else. The word 'nonsense' comes to mind.

 

[altonhare]

Your diagram is with respect to some reference frame. In another frame, it might look like this:
000000000000000000000
0000000000A0000000000
000000000000000000000
000000000000000000000
000000000000000000000
0000000000B0000000000
000000000000000000000
000000000000000000000
0000000000C0000000000
000000000000000000000

(not the same as the numbers I gave earlier but yeah).
Just because you put a grid onto something does not make it an absolute!

All you did was move the B a little closer to the A and away from the C. You didn't change reference frames, you just inexplicably and unjustifiably moved the objects under study around.

You're going to have to justify to me how, at an instant, one person can measure 5 and another 3. So far you have just stated this and "justified" it by showing A, B, and C at different locations.

In the "grid" I showed, I can sit on the A and walk downward. I count 5. I can sit on the B and walk upward, I get 5.

I don't know what significance you are imparting to the word "dimension", but for me any parameter can in fact be treated as a dimension in the phase space of a system.

Dimension: extent of an entity in a direction mutually perpendicular to every other direction

If instead we're just talking about how many mathematical parameters we can assign in our model, one can make an argument for an arbitrary # of dimensions.

What is not an issue that can be resolved mathematically?

And would you not say the same thing about spatial dimensions? If not, why not?

"What is a dimension?" is not resolved mathematically because you don't prove a definition with a measurement or a mathematical model. You just define the word "dimension".

The idea of eternalism is not that "time is a dimension", but that all events throughout space and time have the same ontological status, that there is no unique subset of events that are specially marked out as being in the objective "present".

Entities only exist in present-mode, i.e. they just have location. They are eternal in this sense, that they have no past or future.

Mathematically you can model the relationship between these events in terms of their relative positions in a 4D pseudo-Riemann manifold, but as you say this is a descriptive model, and this model could be used by a presentist too. The point is that if we can make all the correct predictions about physical events using a model that does not include any notion of objective truths about simultaneity, then philosophically there is no irrefutable argument for believing there must be any absolute truth about simultaneity, even though you are still free to take the presentist position which says there is. Do you think this is wrong? If so, please present whatever irrefutable philosophical argument for absolute simultaneity that you think you have.

There are no ontological contradictions.

altonhare:
(my emphasis)
Time is essential in doing physics, just as the passage of time is an inescapable fact of existence. This is a physics forum. You are talking something else. The word 'nonsense' comes to mind.

Passage of time? Like the passing of a car? The hand on my clock rotated, did time go by me? Time is simply relative motion. We could extract time from our equations and model reality just as accurately, although it would be a bit more tedious. All our equations have to do is to tell us successive locations.

 

[Mentz114]

altonhare:

Time is simply relative motion. We could extract time from our equations and model reality just as accurately, although it would be a bit more tedious. All our equations have to do is to tell us successive locations.

If you have successive locations you are including time. Time is what stopped everything being everywhere at once.

Time is not just relative motion. Does time stop in a universe containing only one distinguishable piece of matter ? Thermodynamical time is certainly not merely relative motion.