Friday, October 07, 2005

Relationism vs Absolutism on Space

I've read this chapter about three times now, and I'm a little confused. Intuitively, I'm trying to figure out how absolutism about space would work. Le Poidevin never answers it well enough, he avoids the issue in my opinion. I think obviously that relationism about space is correct. If you take the example of the planets and the sun. If the sun is stationary and the planets orbit the sun but they all orbit in different lengths. Wouldn't the planets be in relative motion to the sun and the other planets? Even if there was only one planet and the sun, the planet would be in relative motion to the sun because the orbit would cause the planet to be a different distance from the sun at certain times. If you guys can think of a logical way to explain absolutism about space with a simple example that would be greatly appreciated.

6 Comments:

Blogger Nigel said...

If you look on pages 46-48 of Le Poidevin, he gives two clear arguments for absolutism about space. Both of them use centrifugal forces (which i gather arent real forces) to explain why absolutism about space is true. To me these arguments make sense, as does the concept of a fixed point in space. We have vacuums in our universe. How hard is to imagine a fixed point inside that vacuum? Now imagine that same fixed point in the vacuum, except everything else suddenly disappeared. The point would still be there, despite the lack of anything else. Now, if there is such a thing as a fixed point in absolute space, anything which moves in the rest of the universe would be in absolute motion.

1:06 PM  
Blogger frankd23 said...

I honestly think that the debate over absolutism and relationism about space is extremely difficult. I had an extremely hard time coming up with a good argument for this upcoming assignment. I really think its a matter of how u define space which makes absolutism or conventionalism right. For example, lets assume our universe is the only universe. Now, its a given fact that our universe is expanding and in order for it to expand it must be either: (1)creating space as it expands (relationism) or (2) expanding into empty space that already existed before the universe actually expanded into it (absolutism). It really just seems that the definition of space is what will ultimately prove which view is right. I happen to be an absolutist but I can't come up with a very strong argument for it or against relationism. I don't think space can be created just because objects have now entered it. Thats my biggest problem with relationism.

1:14 PM  
Blogger Significant Digits said...

I think the problem in fighting relationism or absolutism, playing off what frankd23 said, is that we aren't sure what the definition of space is, but that's basically the pivotal point of each argument. I think we need to assume that there would be a difference between a vacuum and between space, as weird as that seems. A vacuum could have existed before universal expansion, but "space" wasn't created until their were objects in the universe, in which case Relationism would be correct. I doubt there's really any anatomical difference between a vacuum and space, but rather, their definitions.

8:50 AM  
Blogger mparent said...

I think there's a major problem with LePoidevin's argument for absolutism using centrifugal forces, (page 48 I believe). If you consider some system that has centrifugal forces, then the objects inside must be accelerating towards some point. So although the objects may have zero acceleration and velocity relative to each other there is still some point relative to which they are accelerating. Although there is nothing there you can still point at this place as something to which their acceleration is relative.
As an example consider two cars directly opposite each other driving in a perfect circle at exactly the same speed and acceleration. Now, relative to each other the other car is not moving or accelerating. But relative to the center of the circle they are both moving and accelerating towards the center of the circle.

8:19 PM  
Blogger Kermit said...

I don't really see how relationism about space has any argument at all. If you picture a square room that has points marked along the wall, floor, and ceiling like a 3-dimensional coordinate plane, any of the points can exist in space. Even if the room is empty, the points still exist. Relationists might say that space is the distance between two objects, but what about the distance between two objects that do not yet exist? There still must be space there for them to come into.

1:57 PM  
Blogger Darron said...

Absolutism about space is defined as space being independent of all other objects. In other words, according to absolutism about space, space does not require any object, living or non-living, to exist in the world. Here is a slightly complicated example of using absolute acceleration to say that absolutism about space is true.

1. An object’s acceleration is either absolute or relative.
2. An object’s acceleration within the system can be present in the absence of any objects outside the system, and so in the absence of any relative motion.
3. Therefore, absolute acceleration is possible.
4. If (3), absolute space exists as well.
5. Therefore, absolutism about space is true.

12:16 AM  

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