As a teenager, I believed in possibilities.
I believed in the possibility that dead people sometimes hung around their old house, just in case they didn't like the new occupants.
I believed in the possibility that this planet wasn't the only one capable of supporting intelligent life.
I even believed in the possibility that the universe didn't just spring into existence of its own accord, but was the creation of a superior being. (I also believed in the possibility that said superior being kept the universe in a fishtank in his kitchen, but that's not important right now.)
When I became a Christian some of my beliefs were altered, but not entirely thrown out (except the fishtank one).
I believe there is a spiritual realm to the universe, demons and angels, if you like, and that this may account for many of the ghosts people claim to have encountered.
I still believe in the possibility of life on other planets. Why not? Speculation as to how the story of God may have played out a long time ago, in a galaxy far, far away, was what led me to create the Old Testament Space Opera.
It also leads to one of christian sf's interesting dilemmas: If man is created in God's image, what happens when intelligent alien life turns out to have ten arms and no head? or be a shapeshifter? or a super-intelligent shade of the colour blue?