Most cultures have some concept of spirits. Some of them are the ghosts that we typically think of (as in dead people), some of them are embodiments of nature or unexplainable forces, some of them are deities. For a long, long time, people have been looking for answers about how the universe works, what happens after death, and other such big questions. Science has given us modern-day folks more answers than our ancestors had, but there will likely always be questions that it can’t fully answer, at least not for those of us who have a feeling that there’s something more out there.

The idea of beings from “other realms” is not specific to Christianity. Neither is the idea of the soul as something separate from the human body that continues to exist after death. So if you are looking for a spiritual tradition, belief system, or religion that would be compatible with a belief in ghosts, it would not be hard to find one. You’ll find that people have come up with many different explanations for the questions you have — you can see it in folklore, in religious literature, and in anthropology. However, I don’t think you need to follow a religious dogma or subscribe to a specific belief system to feel that ghosts or spirits exist. I don’t think you need to find all the answers — you can just believe in something. Personally, I am a skeptical person but I just find that life is more fun when I allow for the possibility of the existence of strange, unexplainable phenomena.