livbucks, it is NEVER possible to proove somethingDOESN'T exist. You can always make the argument that you just didn't look in the right place or come up with some crazy scenario that leaves open the possibility. It is ALWAYS possible to prove something DOES exist. This is why logical people put the responsibility or burden of proof on the person making the claim that something exists. The saying is, "you can't proove a negative". Prooving a negative is always what the conspiracy theorists and the big foot people, and the lock ness moster, ogopogo, space aliens, crop circles and on and on and on, all ultimately challenge others to do. Proove it isn't so or proove it isn't possible. As far as they are concerned, it's true until proven false. Well no, that's not how intelligent people do things. You claim mountain lions are in PA, you supply the proof. Until you do, I have no logical reason to believe you.

Can you imagine if science worked this way. O.K. I've discovered a new element. I'm going to call it Sylvanium. It's very rare and it destroys itself if there are any negative thoughts in its vacinity. Me and a few of my associates have seen it a few times and we want you all to accept our testimony as proof and add Sylvaniumto the periodic table. You should all do this unless you can show us that we have made a mistake and Sylvanium just doesn't exist anywhere.