First the disclaimer: I'm a hardheaded realist (okay, a cynic) about UFOs, crop circles, and Mothmen. That said, wouldn't it be cool if there were aliens among us?

Here's a bit of information I found interesting: A recent study asked a range of people these two questions:

Are humans the most important species on Earth?

Is there intelligent life on other planets?

People who said "yes" to the first question were distinctly more likely to say "no" to the second. In short, their belief in extraterrestrial life was affected by their values and attitudes about themselves, quite apart from any evidence they may have seen. And I bet you would find something similar about people's belief in extraterrestrial spacecraft.

Which leads me to boldly name five factors that could explain why some of us believe in UFOs:

1. Loneliness. We don't want to be the only intelligent life form in the universe. (Cheer up: We're not that intelligent either.)

2. Insecurity. Earth's problems seem too huge for us pitiful humans to solve. We can only hope to be rescued by aliens from another planet whose civilization is "vastly superior to our own."

3. Paranoia. Even in good times, we feel uneasy. We need some way to explain our irrational anxiety. "Aliens are watching us" does the job nicely.

4. Suspicion. We feel out of the loop. We don't know what's going on. It must be a conspiracy, we think, because the authorities must know, and if so, why aren't they telling us?

5. Truth. Maybe there are aliens spying on us--that would be another way to account for all those sightings!

To sort out these factors, we need to clarify what we do know about the UFO phenomenon: Where do facts end and speculation begin?