The existence of "Ghosts" means...

[CristW]

ChristW, everything's possible, but extremely unlikely based on evidence so far.
#6. Brain neuron glitches
#7 software glitch from the virtual reality world we live in
#8 more than one of the above

That about covers it.

Unless we can study a sample(s), that's about the end of the line for me.
They are unfalsifiable ...fun to talk about whatif's, but that's about it.

After reading the Fermi paradox, I've stopped believing in et's ever having been here.
Although there's plenty of good stuff on YouTube, I take it all with a sack of salt.
Even the church sponsored ID videos sound logical to the untrained mind.

Actually it is called INDUCTIVE argument compared to DEDUCTIVE argument(which requires 100% proof or evidence).

We do not have all the data, like in a Lab, to determine something TRUTH-preserving which is a characteristic of DEDUCTIVE reasoning.

Therefore, INDUCTIVE argument or reasoning is what we have to use to get to at least a STRONG Inductive argument or reasoning. If it contains true premises then it could be COGENT.

Let's use Disjunctive Syllogism ...

1) Either "ghosts" derive from another unknown phenomena OR "ghosts" are from previous dead people.
2) Not derived from dead people.
3) Therefore "ghosts" derive from another unknown phenomena.

Let's use Modus Ponens ...

"""1. If there are "ghosts" from previous living human beings, then the world would be filled(infested) with "ghosts".
2. All living human beings on Earth are NOT all haunted by their past relatives.
3. There are no ghosts!"""

Rewritten:

1) If there are NO ghosts from previous living human beings, then there are NO ghosts.
2) All Human beings on Earth are not 'haunted' by All previous human beings.
3) Therefore, there are NO Ghosts.

Note: There is no need to know the functions,nature and substances of "ghosts"(This sounds like Rene Descartes argument?!) to know some truth concerning the phenomena! You simply have to know the absence of interaction with the living to understand this. For example, NOT ALL LIVING BEINGS ARE HAUNTED BY THEIR PAST RELATIVES!