Common Sense and UFO's

What if several generations of people grew up on an isolated island in the pacific not having any contact with the rest of the world? They would easily believe that there were no other humans and that they represented intelligent life in the universe. An oddity like a jet trail high in the air could easily be explained away as weather phenomenon. The people would likely make theories about where they came from and believe they were the only intelligent life in the universe. Of course, they would be wrong.

Think of any scenario like that you can on this planet. No matter what the scenario, when the people come to believe they are alone, they will always be wrong. We know that, so why do we so easily think we are right when we don’t believe there are extraterrestrials?

When similar ideas or experiences tend to lead to the same result, then isn't that what establishes a line of common sense? By the fact that we find it difficult to conceive of a scenario where an isolated culture of people are really alone on this planet, it would seem to be common sense that an isolated group of people in any situation would also not be alone. Does this prove there are aliens and UFO's? Of course not! But it does show that by the means we use to determine when something is common sense that it should be common sense that aliens exist. And when something is common sense, doesn't that mean it is a good idea to consider and allow for it until and unless it is proved otherwise?

More common sense. What if you were advanced enough to travel to other planets where there is life and by common sense you would expect such life to be hostile, at least in part, to outsiders. Would you make yourself known? Unlikely. Would you go there at all if you did not have a way to protect yourself and effectively hide from the life there? I doubt it. This is just common sense. So why do we need big government conspiracy theories to explain why we don't see concrete proof of aliens? The governments of our planet may be involved with aliens, but if they are, it is common sense that the aliens would be primarily in control of the situation, not our fearless leaders. Whatever we know of it is what they want us to know. Anything else would not make sense. When we are no longer a threat to aliens they will appear ... weather this is right or this is wrong notwithstanding ... it is just common sense.