Heraclitus said something along the line of "one cannot step into the same river twice." Every time I've tried it, I've slipped and fallen on my arse (I've never traveled with an actual ass). Doesn't mean that he (Heraclitus) got it right, but maybe he was on the right track. Reality is short-term, it's ending all the time, but, and here may be the clincher, it is beginning all the time.