The bible has one incident of a dead person being summoned by a witch. It fits better with a general biblical understanding that this would have been a demonic illusion rather than any actual summoning of a soul. In the Transfiguration, Jesus showed Moses and Elijah (in full form, not ghosts) and this would be credible because one is dealing with God here.
The mainstream Christian understanding, and I now have no real reason to doubt it, is that there aren’t any ghosts. There ARE demons, which are angels that rebelled against God along with Lucifer who became Satan. The love of God will repel demons, which are driven by hate of God.
In a way I do agree, that ghosts can be demons. However, even Jesus also acknowledge Ghosts.
“Look at my hands and my feet. It is I myself! Touch me and see; a ghost does not have flesh and bones, as you see I have.†that is what Jesus said.
Not all ghosts are demonic. I have been blessed with a gift to discern. Believe me, I can tell. I have experienced ghosts that have impersonated my mother’s voice - except she was alive back then and my mother heard my voice calling her out - except I was alive and still is.
Yet, I have experience REAL DEMONIC force when I was a little girl. I rebuked it in the Blood of Jesus until another entity intervene.
My dead aunt who passed away back in 1972 appeared to me and my mother in 1997. She was a strong Christian woman.
I had a gut feeling she was trying to tell my mother would be joining her on the other side. Well I was right, mother who was very very close to her passed away 3 weeks later.
Remember Cain and Able?
Then the LORD said to Cain, “Where is Abel your brother?” And he said, “I do not know. Am I my brother’s keeper?” 10He said, “What have you done? The voice of your brother’s blood is crying to Me from the ground.
Your brother’s blood is crying to Me! very telling.
I do have a special gift and so did my mother. Like I said I can decern between evil and good “ghosts”. I think as Christian we put God in a box and refuse to see. If there is a presence and God wants me to know there is, I will acknowledge it. However, I have not nor ever call them to me.
Now yes some say there is no ghosts and that is because they never experience them. Maybe one day they will.