On Tue, Feb 11, 2014 at 1:06 PM, Edgar L. Owen <edgaro...@att.net> wrote:
> Jesse, > > The point to understand here is the very fact that relativity describes > different frames that are BOTH simultaneously true from different > relativistic perspectives requires that there actually is a background > independent of any PARTICULAR frame that all frames are true within.. > In a sense I agree, because I think there is a geometric background involving coordinate-independent truths about path lengths and when paths meet at the "same point in spacetime". I just don't agree that the fact that different frames disagree about which events are assigned the same t-coordinate means there must be a coordinate-independent analogue to t-simultaneity. As always, you haven't addressed my question about whether you think any of the facts you point to in order to make an argument for coordinate-independent simultaneity (without assuming it from the start) fail to have direct analogues in spatial facts about the measuring tape setup. One can assign coordinates to points on the tapes using different coordinate systems that are BOTH equally valid, and yet the coordinate systems disagree about which pairs of points on the tapes are assigned the same y-coordinate, but you DON'T believe this implies there must be a coordinate-independent analogue to y-matching. So there must be something wrong with the structure of your argument about spacetime and simultaneity if there's an argument about space and y-matching that has a perfectly identical structure, yet leads to conclusions you yourself would agree are in error. The only way out of this would be to show the spatial argument *doesn't* have a perfectly identical structure, because if you laid out the argument as a series of steps, there would be some step where we couldn't come up with an analogous step in a spatial argument. Jesse -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To post to this group, send email to everything-list@googlegroups.com. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/groups/opt_out.
