The first group are Darwinists who believe that all that can exist is whatever our senses can know. This group might believe that extraterrestrials do not exist but nevertheless provide frightening material for the psychological manipulation of subhumans, aka unevolved hominids/apes. Some others might believe that since evolution has been occurring everywhere throughout the cosmos for millions or billions of years that extraterrestrials are highly evolved beings who might have seeded earth with life. Others of this group hold that such beings might perceive us as food should they come here
The other worldview group believe in the existence of unseen dimensions, telepathy, spirits, ghosts, walk-ins (temporary possession), and extraterrestrials. To them, extraterrestrials are beings like Hathor, featured in the book UFO of God. At one time Hathor was a highly revered Egyptian goddess symbolized by either bull or cow, making Hathor transexual. Today Hathor arrives in a spaceship as an emissary from the divine one substance. She/he comes bearing great gifts of knowledge such as christ is within you.
.
That's an insult to the graduates of my alma mater (UGA).
Not me of course. I'm not insulted. Being of above-average intelligence, I was never socially accepted as an unevolved hominid/ape.;-)
I am sure you know there are many other possible worldviews on this subject.
My favorite “expert”—far outside the two alternatives you presented:
https://podbay.fm/p/point-of-convergence
The short version of his view is that human perception, technology, religion, philosophy etal is inadequate for this task.
It is like asking ants to explain the existence of humans—it just does not compute.
Our failure to understand what is going on tells us a whole lot about us—and not much about them.