I'm just going to throw this one out there. Alien abductions. What do you think?
George, Hollister, CA
George this is an interesting question. If you were to look at it from only a mathematic or scientific perspective the answer would have to be that Aliens exist. If the universe is billions of years old, is infinite in size and constantly expanding than there would be an infinite amount of planets out there with an infinite amount of opportunities for life to exist. Logically life would have to exist elsewhere because there is an infinite amount of opportunities for it to do so.
But that only answers part of your question. I think you're talking about this and I'm more than a little skeptical. I mean why would Aliens hide their existence from us? Clearly they are more advanced if they have the technology to visit our planet. They have no reason to fear us. I think they'd probably just come down an introduce themselves rather than terrorize us with secret probes. Although then there is the terrible risk of this happening (hint: there are twins and its the second baby that really makes the scene awesome). Also how much are probes really going to teach the aliens about us. There has to be a more effective way of learning about humans and if an alien race has the technology to travel faster than light speed they probably have the ability to study humans that are more advanced than probe insertion. It seems to me that any reasonable Alien race would just introduce themselves or just ignore humans entirely.
In conclusion George I just don't believe there are aliens out there playing weird mind games with us. I would hope that an advanced alien race would have better things to do than kidnap Mulder's sister. But Travis Walton would probably disagree with me.