The argument between different views in the paranormal is ever raging. This scourge plagues the paranormal field and driving huge wedges between investigators and clients.
Usually people are on one side or another before even entering the field of paranormal research (ghost hunting to some), and the bias thrives and can influence views and processes of investigation. Even within the confines of the same group members can argue and never see eye to eye. This can influence the outcome of any kind of research, ghost hunting, or private investigation.
True research can not be accomplished in the paranormal as scientific groups may agree, or religious groups may agree but both groups will never agree. As Parapsychology may make advances and 'prove' ghosts and spirits are nothing but a product of the human mind, those of the religious view would not except this proof. To accept this proof would be to almost say there is no soul, and in turn possibly no god? What if religious groups proved the existence of god?
Results of such research will affect the way people look at religion and possibly shake people's beliefs. Hence the governments excuse not to disclose the existence of aliens!
In today's paranormal, the use of 'mediums' is ever growing and can add yet another view to compete with. Most of these people consider religious as they usually subscribe to one religion or another. Scientific, or Skeptics will usually not believe in this view and be somewhat always at odds with mediums.
As much as people would like to say that they walk into the cases with open minds and neutral beliefs, in their mind the battle is still being waged. Believer, Skeptic, Religious, Scientific, doesn't matter which way someone thinks it will always affect the way someone investigates.
Without an agreed upon approach by all groups, this unfortunately will result in paranormal research not evolving passed it's present pseudo science state.