Tbh, I firmly believe in both. A ghost is nothing еще than a soul that has been earthbound without a body. We as humans have no idea what happens to us when we die, или rather what can happen. We can only speculate, so a Остаться в живых soul doesn't seem at all far fetched to me.
As for aliens, well it'd be pretty arrogant for us to assume that our planet is the only planet the can или has cultivated some life form или another. They may look exactly like us или maybe they are something we could never even imagine but I'm sure they are out there. They might even be wondering about us; doubting our existence.
Of course our understanding of outer Космос is relatively limited too so it's еще speculation
I have a difficulty believing in ghosts just because of the fact I haven't had experience with one. The reason I believe aliens exist because with how large the universe is there must be at least one other species of life other than us Earthlings.
I personally have a far stronger belief in ghosts than I have in aliens.
I just feel like when we have far еще solid proof for the existence of ghosts than we do for the existence of aliens. I could go deeper, but that would take ages, so that's that gist of it.