Tuesday, October 25, 2005

Newton's argument against relationism

At the end of class Chris had proposed a spinning disc, like a washer instead of the rope and ball setup as a counter to using the center point as a point of reference. In order to truly eliminate the center point as a point of reference, then the universe itself must consist entirely of the washer and nothing else. I have a couple of arguments against this setup.
First, there's the fact that there are centrifugal forces which push things outward. This would result in the inner surface of the washer moving ever so slightly away from the center. But if this happened then a point on the inner surface would be moving relative to the other points on the inner surface.
The next argument is that if there was nothing else in the universe there would be no way to know that the disc was actually spinning. Given that the washer is the entire universe there would be no "room" for absolute space to exist and things could only be defined in terms of the disc itself which appears to not be moving. If you allow for absolute space to exist somewhere and the disc is moving relative to it, you've expanded the universe and that space could be explained relative to the disc and so relationism 2 is not in trouble.


Blogger frankd23 said...

I have a response to both parts of your argument. Centrifugal forces would be pushing out of the center equally in every direction. So the point in the exact middle would not be moving at all because the centrifugal forces (which are vectors) would all cancel eachother out and be equal to zero. So this would be a non-moving point that can be used as a point of reference. Since this is the case, we do not need another area of space as a point of reference

7:54 PM  
Blogger mparent said...

If you allow the center point to be included we essentially have the situation we described in class with the spinning balls on a rope. In this case the center point is describable relative to the disc itself so it doesn't mean any trouble for relationism 2. Remember the disc is like a washer so there is no center because we've already countered that argument in class as I stated earlier.

11:24 PM  
Blogger Darron said...

Here is an argument based around Newton's argument against relationism:

1. 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.
2. If (1), then absolute acceleration is possible.
3. Therefore, absolute acceleration is possible.
4. If absolute acceleration exists, then absolute space exists as well.
5. Therefore absolute space exists as well

4:17 PM  

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