Great question and one I have dealt with as I became a full preterist.
I used to believe in ghosts, departed souls and demons impersonating loved ones through palm readers, etc, but that would mean Biblical verses such as 1 John 3:8 (Jesus came to destroy the works of Satan) would be a hollow statement and actually a lie. Jesus said the strong man was bound. (Matt. 12:29). Another hollow victory if Jesus only bound the strongman and not his little demons.
The word "Destroy" has a different meaning in the context of usage elsewhere in Scripture than to mean just crush. The only other time Jesus used the word was when He said he could destroy this temple and he would rebuild it in three days.
The word he used had the meaning of taking all the remaining parts, pounding them into small particles similar to grain, then removing all the particles so that they could never be reassembled. This was the same "Destroy" that John mentions Jesus did to Satan's kingdom.
If that was so, then there is no element of Satan's realm left or Jesus and John were wrong or lied. I choose to believe both were right and we have/are misinterpreting Scripture.
If Jesus said he bound the enemy and John Said Jesus destroyed Satan's work, and Jesus said after his resurrection that He possessed all authority and power (none left to share with Lucifer), but he didn't say that before the Resurrection, then it would necessarily cause one to accept that there really is nothing for Satan to reside over.