If it can be trusted to let the dog out on mornings when I'm sleeping in, then I'll credit it as real. Bonus if it'll also empty/rinse/refill her water dish, and take care of her breakfast. But serious penalties if it isn't reliable about giving her half the can, or leaves a can or lid where she can get at it. (The vet bill from that bloody gash on her tongue was not trivial.)

More generally - reliable, useful, macroscopic physical actions, requiring non-trivial judgement.

The cat is same for me. If it could pick the nightly dead rodent so I don't have to explain murder to the kids every day that would be great.

But ultimately what machine/device could show something? I appreciate not one reading could do this and it would have to be repeatable.

I lived in a haunted house with my parents. My dad is atheist and the most skeptic person I know. When we moved to this old house they fixed the roof and found jars with newspapers and hair inside. Apparently the woman and daughter that lived there practiced witchcraft.

My mother loved to go out with my aunts on weekends. One night while I was sleeping my father heard sounds of high heels in the corridor that had wooden floor. He got out of the room to check whether my mom had returned. There was no one. Being a skeptic he will never tell you that was a ghost.

At another time I was feeling depressed and laying on my bed on a side. Windows closed. I felt this kind of "slow wind" touching my arm. I actually felt better right after that.

And I also witnessed a nasty accident while watching thru the window that's probably too much for HN audiences.

As for a detector, get depressive people inside the house and examine what happens to them.

I have the perfect comic for this.

https://existentialcomics.com/comic/495

On a more practical level, there's a distinction to be made between (A) whether there is something unusual and detectable, versus (B) whether it supports a huge extra set of supernatural baggage.

This distinction is especially important in the related field of UFOs.

That's a great comic, and that's where I sit.

Appreciate the comment, but what would (B) involve?

As I see it, it's all EMF (could be picked up from anywhere), no mass spectrometers, no actual science.

Well, I suppose evidence for the trickier (B) would be if the inexplicable EMF signal also had information telling the widow exactly where to dig in order to retrieve her late husband's buried treasure, or it clearly predicted future events, etc.

That would be in contrast to weird measurements that can't be explained with current science... Buuuut it's a sine-wave that only occur when the neighbors are running their microwave oven. A physicist might get an interesting paper out of it, but it wouldn't upend our understanding of life and death.

Yea agree. It's always something. Rays from the sun, a phone mast or something else. But what signals could be sent that are provable? Even if a ghost told you where to find the money. No one would believe you.

Before they passed, I (skeptic) made a deal with my grandfather (skeptic) and my mother (believer) that they'd do their best to try to communicate with me after they passed. My mom and I reiterated the pact the day before she passed. So far, nothing obvious, except for one strange incident.

Shortly after my mom passed, I was making dinner in the kitchen when I heard, clear as day, what sounded like my mother's voice yell out my name (it sounded like the type of yell she used to get my attention). When I looked over toward the direction I thought I heard the voice, our dog (that my mother found in a shelter for us), was sitting in front of me, intensely staring at me and acting super excited, which was unusual.

Skeptical me just thinks it was some random event. My wife (believer) was hugely annoyed at me for ignoring such an obvious sign. If so, my mom's up in the sky cursing my intelligence, or lack thereof.

That event still trips me out and I think about it a lot, but my brain won't allow me to believe it was anything supernatural.

I'll make sure to remember some prime numbers for when I croak.

Define “ghost” in details and you get your test criteria

Ectoplasm