Of course, there was an element of sheer luck that his prediction turned out to be correct — he was only aiming for an accuracy of 50 percent, after all. In scientific research the usual standard for accuracy is 95 percent or greater. After the Wall fell in 1989, Gott wrote a paper for the journal Nature modifying his formula to achieve that level of precision.
As it turns out, all that requires is a broadening of the initial assumption: Instead of a 50 percent chance that you are observing something in the middle 50 percent of its lifetime, you could say you have a 95 percent chance of observing that thing in the middle 95 percent of its lifetime. According to the Copernican Principle, this is a very safe bet: You’d have to be incredibly fortunate to be observing something either at its inception (the first 2.5 percent of its timespan) or at its end (the last 2.5 percent).