I think they are figments of the imagination.

I used to be open to the idea, not sold on it, but not any more, it's all mumbo jumbo.

Physics.
[independent.co.uk]

What I think doesn't matter. What matters is if it can be substantiated or proven in any way.

My stepson is fond of ghost hunting TV shows as entertainment so I have watched or half-watched more hours of that stuff than anyone really should. These shows are rife with confirmation bias and unjustified presuppositions, begging the question, and just about every other logical fallacy that you can imagine. So-called EVPs (recordings of ghost voices) are particularly spectacular examples of confirmation bias. All it proves is that if you listen to enough highly amplified background noise in any audio you'll be able to pick out a short segment and suggest what it's saying and the listener will go, wow, yeah, that's what it's saying. But on those occasions where I am coming in from another room and am not watching the subtitles on the screen, I will hear something entirely different or perhaps just gibberish. To the point where when they suggest what they claim is being said it does not sound like what they're claiming at all.

That's how all that stuff works -- you have people who are curious and hopeful, in a contrived atmospheric setting (dark, nightime, backstory of some horrible event, spooky old building, etc) in the company of a bunch of other credulous believers or semi-believers, selectively perceiving things out of the corner of their eyes and edges of their perception, according to what they expect or hope to discern. Our imperfect perceptive and cognitive equipment fills in the blanks, and voila -- you have ghosts.

I've even accompanied my stepson to a couple of actual ghost hunts and it's astounding the amount of pre-suggestion that goes on. You're told of what other people claim to have "seen" in the dark halls of the mental institution or whatever it is, and of course, you're going to be staring into the dark and your mind is naturally going to tend to construct from shadows and floaters in your eyeballs whatever they suggest. Unless you're not having any of it, like me, and then you'll not see a damned thing.

I think it's telling that a certain amount of receptivity is key to these experiences; if you approach them at all skeptically and without preconceptions or presuppositions, these experiences don't happen at all or don't lead to the conclusions you're being directed towards. Reminds me of something else that fits that bill: religion.

None of the above.

The same thing I do about god. Absolutely no evidence.