Quantum physics isn't hard to understand, really. Think of it like this: everybody has a lot of different potentials. Five years from now, you could be drinking booze from a paper bag and sleeping on the street... or you could be drinking booze from a china cup and sleeping in a pressurized dome. That spread of probability can be considered the vector of your life.
Of course, five years ago, it was fairly likely that I would be rich, famous, and married by this July. Having actually APPROACHED that time, I can say that the probabilities have not gone that way, and it is highly UNLIKELY that I will meet a girl, fall in love, get married, get rich, and get famous in the next two weeks.
That's quantum physics: the closer you get to the probabilities, the more exactly you know where you are as they collapse, but the less of an impression you get as to the vector of your life. Unless, of course, you look into the future... at which point you know the vector, but it's impossible to tell exactly WHERE in that space you'll land. Until you get there, of course.
Okay, so I'm not so much explaining quantum physics as bitching about not being rich, famous, and married to a genius girl. Still, it's a fun parallel to make.