We have built systems that have detected:

• Black holes which collided 2000000000 lightyears away
• single photons
• neutrinos, particles that can pass through lightyears of lead
• concentrations of chemicals rated in picograms (0.000000000001g) per litre
• vibrations rated at 1/1000000 of a g

We have come into a world where people carry around, nearly 24/7, devices capable of recording high definition video, measuring variances in light, magnetism, vibration, storing time correlated data and even processing over it with enough proficiency to put digital bunny ears or makeup on you in real time.

Despite all this, we have no evidence and no mechanism by which we even might expect ghosts could exist. It’s reasonable to say you can’t be 100% certain they don’t exist, but it is also wildly unreasonable to say they do.

For decades James Randi offered a million dollars for any evidence of supernatural shit that can be tested. Many people tried, but none were able to produce evidence to earn the money.

If ghosts were a very rare occurrence and only 0.00001% of all dead people produced ghosts we would still be completely overrun by ghosts everywhere, they would be mundane in how common they are. And that’s not counting ghost animals, ghost dinosaurs, etc.

The impulse to believe in ghosts can be explained as well. For most of human evolutionary history we had predators (cats, bears, wolves, hyenas, etc). If you heard a noise in the bush and didn’t assume it came from an agent you were more likely to be ambushed than if you assumed it was an agent even when it was just the wind. The survival trait biased us towards assuming agency even when it’s not. When you hear a noise in your home at night your first though isn’t settling foundations, it’s intruder.

No. It’s unreasonable. Tell your friend that I specifically said he’s a twat

Can a person with reasonable beliefs have an irrational one? Certainly.

Can someone reasonably believe ghosts exist? No, it is a unreasonable belief.

He says there’s “convincing “ evidence for its existence.

Big if true. He should send that to you instead of making memes.

It is disturbing when people take this kind of mysticism seriously. I could say a lot about this but it may be best just to refer to the words of Carl Sagan:

“I have a foreboding of an America in my children’s or grandchildren’s time – when the United States is a service and information economy; when nearly all the manufacturing industries have slipped away to other countries; when awesome technological powers are in the hands of a very few, and no one representing the public interest can even grasp the issues; when the people have lost the ability to set their own agendas or knowledgeably question those in authority; when, clutching our crystals and nervously consulting our horoscopes, our critical faculties in decline, unable to distinguish between what feels good and what’s true, we slide, almost without noticing, back into superstition and darkness…

The dumbing down of American is most evident in the slow decay of substantive content in the enormously influential media, the 30 second sound bites (now down to 10 seconds or less), lowest common denominator programming, credulous presentations on pseudoscience and superstition, but especially a kind of celebration of ignorance”
― Carl Sagan, The Demon-Haunted World: Science as a Candle in the Dark

Dude just thinks he’s special. There would be ANY evidence by now. The superiority of the meme is laughable. Your friend is a fool.

Ok, here’s the thing. I don’t remember many dreams from a week ago but to this date I still remember waking up as a kid in the early 90’s and looking down the stairs and seeing two people in period clothes standing at the bottom of the stairs. We lived in a house from the 1800s so it checked out; and given that I genuinely felt a force when I tried to close the basement door, I believe they were basically standing guard between the cellar door and me protecting me.

From my perspective, ghosts are basically the result of…

1. Delirium / psychosis or similar mental illness.
2. Attention seeking.
3. People attempting to explain something they saw/heard/experienced but don’t understand and aren’t open minded or curious enough to explore real answers to.

The question’s a little weird.

Can a reasonable person genuinely believe in ghosts? Yes, obviously, people do and many of them would be considered generally reasonable. They manage their lives okay, they make good decisions most of the time, they’re not gibbering maniacs, they’re reasonable people.

But: is it reasonable (meaning, grounded in good evidence) to believe in ghosts? I’d say it depends on what you and your friend specifically mean by “ghosts”, but in general no. If ghosts were real, they’d be more observable.

And “Hitchens said so” is pretty weak sauce, so I hope that’s an uncharitable summary of your argument.

The bar for “convincing” is very low when you want to believe.

If ghosts were real, then I can think of a few people throughout history who would have been swarmed by them. Adolf Hitler would have approximately 13 million spirits haunting him by the end. Something like 100,000,000,000 humans have ever lived, and somehow all the ghosts are from culturally relevant time frames? For all the US civil war ghosts people have seen, you’d think there’d be orders of magnitude more native Americans haunting this place. Did the European colonists just make sure to let the Indigenous peoples finish all their business before hunting them to near extinction?

I think it’s fine if people believe in ghosts and spiritual stuff. My wife believes in ghosts, genuinely and fervently. I don’t really care to battle her on this because regardless of what she believes and what I believe we ultimately end up doing the same thing in the end - nothing. I think it’s a bit childish, but it’s no more or less unreasonable than faith in a god or a higher power and people will fight you over that.

I think the delineating factor is how much belief in ghosts or the supernatural play into your decision making and your worldview.

If a person believes ghosts are real, but never really act on that belief, it’s harmless.

if a person believes ghosts are real and alter their behavior in meaningful ways as a result, it’s maladaptive.

For example, say you hear a creaking noise in the middle of the night that startles you awake. Person A, Person B and Person C each check to ensure there’s no intruder in the house and determine that all the doors and windows are still locked and there are no signs of forced entry.

Person A comes to the conclusion that it was just the sound of the wood joists expanding or contracting as the temperature fluctuates and goes back to bed.

Person B comes to the conclusion that the sound could have only been produced by a ghost and therefore their house must be haunted, and so they call an emergency priest to come exorcise the house with holy water and they stay up all night clutching charms and wards to fend off spirits.

Person C comes to the conclusion that the sound could have only been produced by a ghost, says a quick (10 second) prayer for protection/guidance for the lost spirit and then goes back to sleep.

You can see how Person A and Person C have conflicting views about the origin of the sound, one which relates to scientific explanations for real phenomena and the other that delves into spirituality and faith to explain it. Regardless, they are both able to resume their normal behaviors (sleeping) afterward, while Person B shares the same view of the origin of the sound as person C, but their view is extremely disruptive and illogical. Their belief in ghosts requires them to take extreme measures to feel protected against them, but there is no evidence that anything bad would have happened as a result if they had chosen to do nothing instead. Nor would there have been a guarantee that something bad would not have happened anyway if they did all of the “proper” things to remain safe from ghosts.

Man, the downvote ratio really goes to show how many people vote without reading a post. I imagine a lot of them would agree with you, but they just saw the meme and thought, “That’s stupid.” Which is ironically a vote in your favor.

no, its unreasonable