A Challenge to Special Relativity?

[Curious6]

Perhaps this thread should be moved to the philosophy section then?

Our discussion has effectively led us to consider the issue from a metaphysical perspective, given that the example I put forth at the very beginning does not contradict SR, is in partial agreement with it, but also proposes a further point (i.e., that besides relative space there is also absolute space), a point which the SR framework cannot test, as you have aptly pointed out.

but just from a philosophical point of view, I don't see what "reasoning" compels us to believe in such a thing, or to think of space as a "fabric" with identifiable points which persist over time. Do you also believe in an absolute coordinate grid, so that there is an absolute truth about what an object's "real" x-coordinate is at a given moment? If not, what makes the idea of an absolute truth about whether an object is moving or at rest any more compelling?

For the while being, given that I am not convinced by any of the proposed counter-arguments, my reasoning does lead me to believe in an object having a 'real' x-, y-, and z-coordinate. This all follows from the simple observation that we agree on where objects are once we take into account our specific reference frames. I am in no sense an absolutist or have any preference for an absolute space, I am just saying that even taking into account SR we can be led to conclude through the reasoning expounded through my first example that there are absolute space coordinates.

 

[Mentz114]

Yes. Let's stick to Newtonian physics. The location of an object is absolute. The description of where the object is relative.

Let's have 2 objects for convenience. The vector pointing from one object to the other is absolute. But you can represent that vector in many ways. If you fix one set of axes, that vector will be some set of 3 numbers {rx,ry,rz}. If you use a set of axes rotated, the same vector will be described by a different set of 3 numbers {sx,sy,sz}. In Newtonian physics, there is an absolute number called the distance d between the two objects that can be obtained from either one of the relative descriptions:

d=sqrt(rx²+ry²+rz²)=sqrt(sx²+sy²+sz²)

I have to disagree with this. What you have shown is that position is meaningless but length or distance is not. Position can only be described by using a frame of reference, so absolute position implies an absolute frame. But we know that any frame can be chosen to be the absolute frame without changing any physical laws. So why bother ?

Curious6:

I am in no sense an absolutist or have any preference for an absolute space, I am just saying that even taking into account SR we can be led to conclude through the reasoning expounded through my first example that there are absolute space coordinates.

I don't follow your reasoning. "Basically, space is relative until we take into account the position of others, then space ceases to be relative."
What do you mean by 'space' ? Distance ? Or position ? You can't define distance without something to have distance between, and position is just something that some observer marks on a map.

 

[matheinste]

Hello Curious6

Quote:-
---For the while being, given that I am not convinced by any of the proposed counter-arguments, my reasoning does lead me to believe in an object having a 'real' x-, y-, and z-coordinate.------

If you have coordinates they are referred to an origin. So an object in space can be located with reference to this origin. But how do you specify the location of this origin. If you specify its coordinates these must be referred to something else and so on and son on. And of course you cannot specify the first origin as being at coordinates 0,0,0.

Matheinste.

 

[JesseM]

For the while being, given that I am not convinced by any of the proposed counter-arguments, my reasoning does lead me to believe in an object having a 'real' x-, y-, and z-coordinate.

I think you may have misunderstood what I meant--do you really believe that there are three objective universal coordinate axes with objective positions in space, regardless of how humans choose to define their own coordinate systems? And that there is a single unique position in space that is "really" the origin where these three ghostly axes meet?

 

[atyy]

Position can only be described by using a frame of reference, so absolute position implies an absolute frame.

I'm thinking that one could do something like this, where there are absolute objects, and no coordinates (frame): http://www.math.umbc.edu/~campbell/Math306Spr02/Axioms/Hilbert.html

 

[Mentz114]

I'm thinking that one could do something like this, where there are absolute objects, and no coordinates (frame): http://www.math.umbc.edu/~campbell/Math306Spr02/Axioms/Hilbert.html

Atyy,
in Hilbert space only direction of the vectors is significant. So defining a 'position' is tricky if not impossible.