I was watching the 2nd part of the “Nova: Fabric of the Cosmos”, and they were discussing the laws of Physics and how things running in “reverse order” are not out of the realm of possibility. Brian Greene explains during the video that it is a matter of odds (I’m perhaps erroneously paraphrasing), there is only one way for an object to be ordered but a vast amount of ways it can be disordered.
This means that statistically you will continue to see things falling apart. I have a theory, at least to why we never see things running in reverse. Lets say you were in a region that was experiencing a “reversal” of time. I would suspect that your body would not be the only thing going in reverse, your senses too would move in tandem. You would be unaware that you have time travelled because your body has rewound in sync with the clock around it.
If someone could reverse “you” you would be totally unaware of this, it would be impossible to sense because all of your sensory systems would be self contained in the event itself. You would see nothing desync about the events in your life. Things would reverse, memories would be unwound, and you would be as you were in that moment that you’ve been reversed to.
Lets say you were to reverse 30 seconds, some great destructive event had occurred and you wished to go back to before it had happened. This would dip into the world of fatalism, because in theory you would go back to exactly as you were before the event. So assuming that no other influence enters the situation it would likely unravel in the same way, but as with entropy before there are many ways the event can end. So perhaps the event would happen subtly different, each time.
This is assuming that you reverse with it. What if you merely observe something go backwards in time but you do not. I would think that you still would not be aware of it. Nothing would feel out of order because your mind would process it with the same systems. If you were a program, which I suppose it could be argued you or I are, and someone changed your coding without making you aware of it, you would not know that anything out of the ordinary has happened.
You would have no personal device to tell you something was wrong, because the devices themselves would be fundamentally changed. To watch a glass recombine would be no more strange to your brain than to watch it break apart. You might even instinctively grasp the glass once more, and everyone observing the situation would be none the wiser.
At the end of the party you are just another person who finished your drink without incident. Unbeknownst to all around you.
That’s my thoughts on the matter, at least.