The problem is the general view of reality people hold. I've said in the past that Jesus himself could return to the Earth, and a lot of people would initially probably think it was BS, they were hallucinating/dreaming, or the devil was playing tricks on them. Most people are set, at least subconsciously, as not recognizing anything beyond the "norm" they see every day as possible. But, of course, science has shown us that even what we consider normal and stable is, when you get right down to it, not really either of those.