And there are some FReepers that are adamant that we’re alone in the galaxy, if not the observable universe. With at least a hundred billion stars at the low end, we cannot be alone.
On top of that, the Bible tells us that there are other beings in other dimensions.
The odds of the right sized planet at the right distance from the right class of sun with the right sized moon and being tilted at 23 1/2 degrees narrows it down a smidge.
There are those of a religious bent who believe that the Bible is clear about there not being sentient life anywhere else in the universe.
The Bible states that Jesus died once for our sins. But if that is the case then Jesus couldn't have been born, lived, preached, and been crucified on multiple worlds. But if Jesus didn't appear on other worlds then it would be cruel for God to create those sentient beings and give them absolutely no clue as to the One Way to salvation.
So these folks tend to believe that if there are UFOs that are not weather phenomena or military exercises then they must be demons.
It will be interesting if there are aliens and they do make themselves known to us. Most people will treat them as other beings that we either can work with or have to fight against. At the same time there will be a huge number of traditional religious folks who will believe them to be demons and act accordingly. Could be very chaotic.
"To consider the Earth as the only populated world in infinite space is as absurd as to assert that in an entire field of millet, only one grain will grow." -- Metrodorus, 4th c BC Greek philosopher
"Heaven and earth are large, yet in the whole of space they are but as a small grain of rice. How unreasonable it would be to suppose that, besides the heaven and earth which we can see, there are no other heavens and no other earths." -- Teng Mu, 13th c AD Chinese philosopher