Why do some people insist aliens don't exist

We don't even know how big the universe is so why rule out the possibility of other life?

I mean do you really think we are so special that we are completely alone?

There is simply no point in concerning ourselves with speculation.

"there must be..." is simply an appeal to a belief you already hold. without some physical evidence, or a podcast from Betelgeuse or something, there is no reason to believe on thing or another. Belief is the enemy of reason.

It might be that they are too afraid to believe, and more than half of the world is simple minded enough to believe that we are the only beings in the universe. Also most of the people who claim to have been abducted tend to look like they are on drugs or have a mental disease... Some people are just hardwired to be skeptical :/ I do believe in them, but I don't believe that they come to abduct the lesser intelligent species.

I don't know anyone who insists aliens don't exist. I, and many others, simply acknowledge the fact that their existence is simply not yet proven, by any real scientific standard. The ravings of the lunatic fringe certainly are not proof; the opinions of people who get their opinions from the media aren't proof either. Proof will come only with their discovery... alien DNA-analogs sampled and examined by biochemists, aliens (alive or dead) being physically examined, that sort of thing. Be honest... would you convict a person of murder based on evidence no better than has been forthcoming? Remember, "skeptical" is a compliment- it means you are careful about what you believe. "Gullible" is an insult- it means you *aren't* careful about what you believe.

With knowledge of the vast number of stars and solar systems. The discovery of planets outside of our solar system; it is improbable for there to not be life other than us. I believe there is intelligent life such as ours in the universe. The likelihood we have been visited, I don't think so. The science to travel across the vastness of galaxy is just incredible. If aliens did visit us, we would be in big trouble. Consider this. The chimpanzee, our closest relative, shares 98% of the same DNA. We split atoms, chimps split nuts. We live in great cities, chimps live in pocket wilderness. If an alien species shared 98% of our DNA, but they were the scientific superiors; it would be like 2003 us meeting 23 century Star Trek us.