Not to nitpick, but the fact that we can't rule out that possibility is nothing special.
You cannot rule out the possibility that when you drop a ball it won't fall to the ground. Empirical reasoning does not operate in absolutes. Only inductive reasoning operates that way.
"Empirical reasoning does not operate in absolutes."
Precisely, and so 'rule out' shouldn't be taken to imply an absolute ruling out of things. =)
Perhaps I should've said effectively ruled out. Life on the Moon has been 'effectively' ruled out (lack of liquid water, no atmosphere, full exposure to radiation and impactors, etc.) - but many years ago it wasn't extremely unreasonable to suppose that life might exist there. Now we know better - we'd have to reach for very convoluted scenarios to argue for the existence of life on the Moon. The same is not true for Mars (although it's not a picnic, obviously), which I would say is remarkable - there aren't many celestial bodies that have passed that test.
You cannot rule out the possibility that when you drop a ball it won't fall to the ground. Empirical reasoning does not operate in absolutes. Only inductive reasoning operates that way.