Do you believe in UFOs? Little green men? The flying saucer crash at Roswell?

You scoff and say, “Hallucinations! Mass hysteria! Cheap drugs!”

Even if you do believe, you probably don’t admit it to just anyone, content to watch reruns of The X-Files in private. Yet it’s perfectly acceptable to be a supporter of the SETI project—the Search for Extraterrestrial Intelligence—in hopes that scientists will discover irrefutable signs of alien life elsewhere in the galaxy with intelligence like our own or greater. I can’t say why one belief is more creditable than the other, but the bigger question is: why do we humans feel such a strong need to believe that there is other intelligent life in the universe? Are we so disenchanted with our billions of fellow Earth dwellers that we hope beings from elsewhere will be better company? (Don’t get me started on the subject of rush hour drivers.)

The concept of non-human intelligent beings probably goes back to the beginnings of our own consciousness. Gods, demi-gods, angels and demons, plus any number of supernatural entities have populated human thought since the earliest of times. Sightings of Unidentified Flying Objects have been recorded for thousands of years too, including an account of “fiery discs” in the sky over Egypt in 1440 BC, a molten silver object shaped like a wine jar that descended into the middle of an ancient Roman battle, and shields that spat fire andswooped over the army of Alexander the Great. Long before Roswell came stories of a chaotic battle of multi-coloured discs and globes in the skies over Nuremberg, Germany in 1561, and something similar over Basel, Switzerland a few years later, with both events depicted in woodcuttings. There were reports of alien spaceship crashes and attempted abductions as early as the 1890’s. I’m not sure about the first accounts of people being “probed” by aliens—they sound more like stories concocted to keep teenagers away from Lovers Lane. But UFO reports were so numerous in the U.S. in the mid-20th century that the American government felt compelled to order its military to investigate, most notably with the U.S. Air Force’s Project Blue Book from 1952 – 1968 (which concluded that there was no evidence UFOs were extraterrestrial vehicles—but what do they know?)

It’s probably safe to say that the very first self-aware ancestors of ours looked up at the night sky and wondered if those sparkling points of light were alive. As the idea gained acceptance that the stars were actually other suns like ours, we were compelled to wonder if those suns also had planets, and if those planets had borne children. If they had, and if those children happened to be older and smarter than us, would they someday come to visit? Was it inevitable that they would?

We have to remember that the belief in otherworldly beings far pre-dates any scientific support. It’s only in recent years that our space telescopes and other instruments have produced solid evidence that other stars do have planets, and although some of the planets appear to be close enough to their suns to support the kind of life we’d recognize, there’s no data to confirm that such life exists. Worse, in spite of decades of dedicated searching, there’s been no sign of advanced civilization anywhere beyond the Earth—no froth of radio noise, no TV shows, no electromagnetic shouts of “Is anybody out there?”

Why do we still believe? Why did we ever believe?

Maybe it’s because we just want new friends. We are social animals, after all—refreshing new company might be nice. Or maybe it’s our species’ burning curiosity—we have hopes that an older, more advanced culture might have the answers to questions of science, medicine, and philosophy that have so far eluded us. Perhaps even the meaning of life itself! It could also be that some inner part of us recognizes the need for a mentor—a parent or teacher figure—who can lead us past the pitfalls and blind alleys as we make our way out into the universe. Or it could simply be that, in the same way we can’t truly comprehend non-existence (like death with no afterlife), neither can we comprehend a whole vast universe with no other beings like us.

Science fiction writers thrive on “what if” scenarios: imagining the possible consequences of different histories, geographies, social structures, and technological developments. Real alien species would provide rich fuel for all that inquisitiveness. But the truth is, it would just be so damn cool to meet an actual alien from another planet, green-skinned or not.

Just as long as they leave their probes at home.