Spirits and Free Will
The majority of cases in which there is spirit activity in the home is because someone invited it or them in. People who have practiced magic, dark magic, rituals, Ouji boards etc used their God given Free Will to open the door to spirits. Sometimes people who have not done this move into a place where this has occurred. In this day and age many people are interested in the spirit world. It's okay to read some books on the matter. But please don't start ghost hunting,try to talk to spirits,use Ouija boards etc. Just because your home is old and feels creepy doesn't mean there are spirits. Too many people are invited spirits in and the ones that most often enter are negative spirits. Again it's great to be interested in the paranormal but don't invite or try to invite spirits in.