Extraterrestrial life does exist. We know this from the mathematics. There are so many stars that are like our own that reason dictates that in some solar system, not unlike our own, in some galaxy, not very much unlike our own, somewhere in this vast universe, there most certainly is life of some kind or another, but life absolutely. There is no reasonable argument against that point of view. Most every astronomer on the face of this Earth will bet his last dollar that the aforementioned statement is the truth. That's plenty good enough for me and should be plenty good enough for anyone else.
Now, does that mean that any of these "aliens" have come calling at our doorstep? It most certainly does not. There is no evidence that can not be refuted in any of a hundred different ways to prove that we have been contacted by any form of life that did not find it's origin on this planet. None of any kind whatsoever.
Any number of people can and have said that they were an eyewitness to the antics of some extraterrestrial vehicle flying through our airspace or having landed out in their fields. Ask anyone who investigates crimes or these types of sightings for a living and they will be quick to tell you that there is often times nothing worse than having an eyewitness. Eyesight can fail, or can be tricked relatively easily. If you doubt this statement watch a really talented magician at work sometime soon and see for yourself. That should make the point unless, of course, you are in the minority of people that believe that David Blaine or Chriss Angel really can levitate.
Physical evidence is key to proving the existence of such encounters as I have just alluded to in the paragraph above. However, none exists. That's right, none. Crop circles have been proved to be work of industrious, albeit, inconsiderate people. Yeah, people. Just like you or me. Only they seem to have a lot more time on their hands.
Throughout the history of U.F.O. sightings not one person has ever managed to liberate a piece of "alien" debris and make it public. Not one picture exists anywhere that shows, without question, a craft or a being that can stand up to scrutiny and the history of these sightings is a very, very long one, indeed. Of all the abductees that have come forward through the years not one has been able to prove his or her case beyond a shadow of a doubt.
Of all the, so called, U.F.O. researchers that are hard at work trying to break the real story of the U.F.O. conspiracy, not one has anything to offer that doesn't fall into the realm of speculation. Stanton Friedman, who has worked in this capacity for a very, very long while now, has no more to offer us in the way of concrete evidence than he did when he started. The "Majestic Twelve" papers are laughable on their face. His investigation into the Roswell incident proved nothing except that the government wanted to keep "Project Mogul" under wraps and put out a few too many cover stories than were really needed. There is a complete and utter vacuum of evidence to support that claim that the "aliens" are among us.
Believe me when I tell you that no one would be happier than I would to get a look at what life from another planet might look like. I'd love the chance to understand any technology that would make interstellar flight a viable possibility for mankind. But, as Carl Sagan once said - and I'm paraphrasing here - "I'll believe when I'm close enough to them to read the license plates". The "aliens" may get here someday, they truly might, but I'm certain that none of us will be here to greet them when they arrive.