How could time flow backward?


I learned in a recent post that time is an abstract concept and thus it isn’t strictly speaking *real* like matter is; time is more abstract like the meter. I think. So imagine my confusion when I read that under certain circumstances time can flow backward! How can this be so, if time isn’t a real thing? You can’t have a negative meter, for example, at least I don’t think. (or can you?)

In: Physics

A lot (probably ALL) of physics involves modelling. Ie finding ways to explain and predict things using mathematical abstractions of reality. It is useful to know that these are all models not the actual thing. Yes, certain mathematical models of the physics “allow” for the construct of particles moving “backwards” in time. Until there is real observational data and experimental validation, the artifacts from these models cannot be taken as proof or indication that anything like that actually occurs or exists.

Any reputable physicist will tell you that they are absolutely certain that the most current models of physics (at the smallest level) is incomplete (glaringly so, since it hasn’t quite managed to incorporate — gravity, the thing that makes the biggest objects in the universe “work”).