Does the Past Still Exist?
The article does not even discuss the obvious alternative that is perfectly consistent with relativity: all events in your past light cone "exist" (a better term would be "are fixed and certain"). This avoids all of the issues mentioned in the article while not committing you to the "existence" of anything that might not be fixed and certain based on the information you have at any particular time.What always amazes me about discussions like this is how even physicists who are experts in relativity fail to see the obvious implications of the fact that, in relativity, spacetime is divided into three regions instead of two. Instead of just "past" and "future", there are "past light cone", "future light cone", and "spacelike separated". "Past light cone" and "future light cone" behave more or less like our intuitive concepts of "past" and "future"--the past light cone is what is fixed and certain and can't be changed, and the future light cone is what can possibly be changed based on things we do here and now. But the spacelike separated region is not like anything in our intuitions, since it is not fixed and certain as far as we know here and now, but we also can't do anything here and now to change it.But instead of recognizing all this and considering its implications, discussions like this article talk as if the only way to divide spacetime up into regions is "past" and "future" separated by a "now" slice (and the "now" slice is of course frame-dependent so it can't have any physical meaning), or to talk as if the only thing that "exists" is the single point in spacetime that is our "here and now". It's disappointing.