If we're using the Bible as a guide, most paranormal phenomena are demonic in nature. It's especially evident when these spirits start talking about Jesus.
We have every reason to believe the Witch of Endor actually set up a meeting between Saul and the late Samuel. So, divination, while forbidden, can work if Providence allows it.
As for the dead, they don't make any Biblical appearances on their own. Also, the Biblical view of the afterlife is pretty cut and dry- you die and go somewhere. No sticking around to go on that last walk through the park.