Saying God exist does not make it true.
Saying God does not exist does not make it true.
In other words saying anything is or is not does not make it true, but the possibility exists that it is.
Better example:
Saying that there are (or are not) invisible flying elves circling my head at all times, keeping me safe from the mind-control rays of the CIA, does not make it true (or false). It is possible that it's true; it's possible that it's not.
It is, however, quite sensible to operate under the assumption that there are no invisible elves and no CIA mind-control rays, unless someone can show you evidence that these things even exist.
"I know some of you are going to say 'I did look it up, and that's not true.' That's 'cause you looked it up in a book. Next time, look it up in your gut."
-Stephen Colbert