Are people's mind playing tricks on them when they claim they have seen ghosts and paranormal activity or are they really seeing this?

You decide: The healthtap team is focused on natural science and are impressed by what it's done for humankind. Members will differ regarding the possibility of "the reality of the unseen". Accounts from people who report events accurately during their resuscitation impress many physicians; this is also an area in which the "will to believe" and the impossibility of experimentation make certainty impossible.

How can we be sure?: It is hard to know about things that we have no way to know for sure about. There are people who have auditory or visual hallucinations, but we do not (and may never) understand everything about ourselves or about the world around us. And i think that is okay because it stretches our minds to think about these things and be open to learning.

No they are really : seeing ghosts. Best to believe them. Ghosts usually show themselves to those who can see or those who they know and want to deliver a message. Newer machines can measure the energy of ghosts and capture them on film. Hope that helps. Good luck.