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The GP's statement sounds like a tautology. Is there a substantial difference between "from our point of view" and "as far as we are concerned ... in reality" u

• pdonis 4y ago
  > The GP's statement sounds like a tautology. Maybe it does to you, but it isn't a tautology. It's a false claim. See below. > Is there a substantial difference between "from our point of view" and "as far as we are concerned ... in reality" under the theory of relativity? Yes. A "point of view" in relativity (by which is meant something like a coordinate chart or a reference frame) might not be capable of describing all of reality. So you cannot infer, just from the fact that a "point of view" does not contain some particular event, that that event is not part of reality. Before you can draw that inference, you first have to show that the "point of view" in question is capable of describing all of reality (which in relativity means all of whatever spacetime manifold you are dealing with). The "point of view" the GP is trying to use is not capable of describing all of the spacetime manifold we are dealing with. So it does not justify the claim the GP is making, that any event not described by that point of view cannot be part of the spacetime manifold. > Using the mathematics of a physics theory to deny a tautological(?) statement Is not what I am doing. I am using the mathematics of relativity to correct a wrong claim by someone who (apparently) doesn't understand that mathematics properly. Everything I am saying is basic general relativity and can be found in any GR textbook.
• pdonis 4y ago
  > the very issue that Sabine is raising in the original article. Doesn't have anything to do with the mistake the poster I have been responding to has been making. Sabine is talking about people who understand a given theoretical model but aren't willing to give it up when it either fails a test against experiment, or is shown to be in principle untestable by experiment. The poster I have been responding to does not understand the theoretical model being discussed, so is in a different position from the people Sabine is criticizing. > Alternatively, you're literally arguing that the mathematics of the theory of relativity bears no meaning in reality. I am arguing no such thing. I am simply making clear that, like any physical theory, GR has parts of its math that represent physically meaningful parts of reality, and parts of its math that represent human conventions that make calculations easier but have no physical meaning. Coordinate charts/reference frames, which is what the poster I have been responding to means by "point of view", are in the latter category. But invariants--quantities that are the same regardless of any choice of coordinates or reference frame--are also part of the math of GR, and those do have physical meaning.