- #176
PeterDonis
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Ebeb said:That's what Einstein meant by his 4D existence quotes
You can always put different interpretations on vague ordinary language, even Einstein's. I interpret that quote from Einstein as saying this: relativity tells us that "3D worlds" do not exist; what exists is 4D spacetime. Cutting up that 4D spacetime into slices called "3D worlds" is a human artifact; nothing in the actual 4D spacetime corresponds to it.
If you want to say that your interpretation is more accurate than mine, then you need to find something in the actual 4D spacetime--not just a coordinate choice, but something actual, physical, observable--that picks out a set of "3D worlds" from that 4D spacetime. In flat spacetime, there is a way to do this (by picking global inertial frames); but as I said in my previous post, the special properties that allow you to do that don't exist in curved spacetime.