Well, if you can factor out every other logical reason of a sound,sight,smell that is made then it is possible. I am a believer in ghosts, but do not believe everything that I may hear or see.
You have to take every variable in consideration and it may be possible that paranormal activity exists. New technology such as thermals,camera, evp (electronic voice phenomenon) helps us.
Just remember these devices help, but there are still logical reasons out there. If you can eliminate those reasons then paranormal evidence can be true. Similar to what the ghost hunters do. Always be a skeptic UNTIL something very strange happens to the point that basic logic does not exist in the equation.