The different sciences tell us different things. Physics, for instance, tells us that every atom has a current state, and that its prescribed future state, and the state after that, is fixed to the point where, if you could chart the position of every atom in the universe, you could then calculate what every single atom will do and then do again, until eternity, and you would therefore have predicted the future.
But computer sciences point out that even though processing power will continue to increase at an expenential rate, it will never reach the point where it can chart the position of every atom in the universe before said atoms have moved, simply because it too will be comprised of those self same atoms, so maybe it's easier to just let the universe run as its own computer simulation, and we'll see how it ends up simply by letting it happen.
Certain branches of philosophy on the other hand, state that reality does not exist except as we percieve it. Indeed, certain psycologists and even biologists will agree with them on this point, since so much of what we feel we are receiving from our senses is either extrapolated by the brain or even flat out invented. What we think we see, we might not see, and really, reality is as we percieve it, and we percieve it from within, each of us telling a different story of what did, and what will, happen. None of them are necessarily right or wrong, since we only ever see them from within our own brains, and even factual innacuracies can be glossed over if you believe hard enough.
What's the point of this post? Well, physics says it was inevitable, computer sciences says it was possibly a waste of the processing power of the desktop to simply type it up in a practically ancient program like notepad, and psychologists and biologists will say that I only precieved the creation of this post, and that it's possible that the physical universe about me that I feel it was typed doesn't actually exist at all.
Thing is though, life will go on, no matter what, real or not. Even once we're dead, the universe will continue to turn (though not the universe as we perceive it, unless we have moulded enough minds to see the world as we do, and even then, not exactly) since, whether or not we loose that 21 grams at death or not, there's plenty of momentum behind it already. Shit's gunna happen, no matter what, and once it's happened it's inevitable that it would have happened, and all you can really do is carry on.
For the record, yes, I am about 6 ciders into the night, feeling philosophical, and no, noone has died. But, in much the same way that it does every instant of every day, tonight, our lives changed irrevocably. Tomorrow will never be the same as today was, but that's life. And now that that's been spell checked, I'll be out in the bar living said life if anyone wants me.