Stephen Hawking had a wager with another scientist. He said I thought we'd be able to reverse time at one point. The universe is expanding so he thought when the universe began to contract time would reverse. He said I made a mistake. As far as we know, the arrows of time move forward: 1. Thermodynamically, thats one measure. 2. Psychologically, in how you perceive time. 3. Cosmologically, the way the universe is moving.
There are two camps of physicists: A. Time is an illusion/human construct. B. Time is a measurable physical force/aspect of the universe.
we can indeed measure time and various "laws" involve it.
A is correct in the larger Omniverse sense, where everything that can exist always exists.
Einstein said that this is merely an illusion (albeit a persistent one).
On a quantum level, everything appears to be reversible. (@sserafim I have a followup on this for your entropy question comparing a cooked steak…)
"Look at the stars, Clark. Some of them have been extinguished for thousands of years, but their light is only reaching us now. The past is always influencing the present. I can't change that. All I can do is try to understand it."
- Lex Luthor, Smallville
Some people live in the past: they dwell on it and can't move forward. Some people live in the future: they dream of it and can't enjoy the present. Some people live in the moment and enjoy the present.
I think it's important to put the past behind you and move on. Learn from it so you don't repeat mistakes. And to look to the future with optimism and hope by building a better future now. Use the time to have to build a better tomorrow and enjoy the present as much as you can. I think it's important to plan for the future, learn from the past and seize and enjoy the present. Memory happiness is also another form of happiness from a neuroscientific standpoint.
The billionaire Charlie Munger said:
"There's no way that you can live an adequate life without many mistakes. In fact, one trick in life is to get so you can handle mistakes. Failure to handle psychological denial is a common way for people to go broke."
"Forgetting your mistakes is a terrible error if you are trying to improve your cognition. Reality doesn't remind you. Why not celebrate stupidities in both categories?"