"Actually according to the laws of quantum mechanics, history is just a set of possible histories with various probabilities of occurring."
Wrong. The past is fixed; no multiverses going backward, only forward. That doesn't mean that those with a political or cultural axe to grind won't keep trying to put their particular spin upon that fixed history, though.
Yes there are multiple quantum states, but according to Schrodinger Cat Theory, once you take action you're quantum state has been decided...even if all states exist at the same time, relative to that decision.
Thus the cat eats the mouse...it tastes good. For that cat the mouse was good, it's history is that the mouse was good tasting. Now for a Cat in a different quantum state where the mouse was bad...his history is the mouse tasted bad.
So relative to the individual, regardless of multiple states, an exact history for that individual can be defined.
According to string theory, there is another dimension only trillionths away from the one we are in and it probably has a different history. Yeah; and there are suppose to be 11 of them....including ours of course.
String theory makes me feel like I can pass a string in one ear and out the other without disturbing anything.
quantum mechanics: the dreams stuff is made of.