> Another thing is all of these systems have probability travel in a single direction. Things with high probability are more likely to happen. If time were to go backwards, low probability events will start to spontaneously occur.
If I shoot a pool ball to strike a heavier second ball which is at rest they will end up moving in opposite directions. If "time were to go backwards" - whatever that means - they would approach at the end one would be at rest. That's seems indeed unlikely with "time going forwards" because we wouldn't be able to do that if we tried (at least not systematically).
I don't think there is a conceptual problem or anything surprising there: we know how balls move given their initial conditions but we cannot control those initial conditions with the precision required to obtain a precise outcome.
There are also cases were we can prepare systems in the right configuration and produce "low probability" events even with "time going forwards": https://en.wikipedia.org/wiki/Spin_echo
>If I shoot a pool ball to strike a heavier second ball which is at rest they will end up moving in opposite directions. If "time were to go backwards" - whatever that means - they would approach at the end one would be at rest. That's seems indeed unlikely with "time going forwards" because we wouldn't be able to do that if we tried (at least not systematically).
in a vacuum no ball will ever go to rest if it's moving. It will move forever because there is no resistance.
What's happening in the pool table is that the ball is losing it's movement energy to the table. Table is absorbing it, the air is resisting it and slowly that vibrational energy becomes more and more spread out until it's basically imperceptible heat (which is also technically atoms vibrating).
What happens when time goes backwards is a bunch of tiny low probability events start happening. Heat from the background vibrating atoms by pure random luck happen to align and happen to produce motion that's noticeable. This happens from several places and by pure luck all of this vibrational motion concentrates on one place, the pool table and the ball. The kinetic vibrations just happen to push the ball slowly in one direction more and more with all kinetic vibrations by pure luck speeding up the ball. The ball being picking up speed until you with the tip of the pool cue catch the ball and ease it into a perfect stop, absorbing all the kinetic energy into the stick and your body.
All within the laws of physics but all extremely low probability events.
>There are also cases were we can prepare systems in the right configuration and produce "low probability" events even with "time going forwards": https://en.wikipedia.org/wiki/Spin_echo
When you put an intelligence in the system it's sort of cheating as you can manipulate random events to be non random and thus violate the laws of probability by intelligent choice. There's some computational theory here that states that the act of thinking itself produces entropy thus it's sort of conserved in a way but that' some other theory stuff that's another rabbit hole to dive into.
If in “time going forwards” a ball hits another one at rest and you “reverse time” right after the collision won’t the “time going backwards” get that ball in rest again? (You’re the one who mentioned physics being symmetrical.)
The point is that with just two things interacting with “time going backwards” you “predict” unlikely things to “happen” and we know that it’s because the “initial” conditions are the exact ones that would make such things happen. It doesn’t seem a big mystery.
In the “many, many, many, we-don’t-even-know-how-many” things interacting case we would encounter something similar. The “initial” conditions if we had “time going backwards” are much more unlikely and the “outcome” much more unexpected because in reality we don’t know almost anything about the state of the system. But we know that those “initial” conditions are “special” - it’s not more mysterious than the simpler case.
If I shoot a pool ball to strike a heavier second ball which is at rest they will end up moving in opposite directions. If "time were to go backwards" - whatever that means - they would approach at the end one would be at rest. That's seems indeed unlikely with "time going forwards" because we wouldn't be able to do that if we tried (at least not systematically).
I don't think there is a conceptual problem or anything surprising there: we know how balls move given their initial conditions but we cannot control those initial conditions with the precision required to obtain a precise outcome.
There are also cases were we can prepare systems in the right configuration and produce "low probability" events even with "time going forwards": https://en.wikipedia.org/wiki/Spin_echo