I've always loved well-done ghosts. However, I've always hated the afterlife-speculation that they engender if used in a story. So I need a way to get ghosts without the fluffy spiritualistic bits. This is not a value judgement on the afterlife, I just don't want to cheapen the concept with easy answers.

If we can get a purely 'materialistic' ghost, some sort of system to preserve and project the memory of a person or important event, that would make me much happier.

What defines an acceptable ghost:

  1. Must be perceivable, and if possible by multiple people simultaneously.
  2. Must be immaterial in some sense (i.e you probably should not be able to grab it by the collar) Nonetheless, I would like my ghosts to be able to generate sound.
  3. Must resemble some formerly living person in some essential aspect (visage, patterns of behavior, speech if possible). I would love it if they were partially sentient/aware and thus interactive and endowed with a deceased person's memories (at least up to a point), so they would (mis-)recognize people and could be persuaded to share their secrets.
  4. This is not vital, but if they need to be killed put to rest, I would love for a way to do so.

So, how do you construct a ghost?

EDIT: I was asked if I wanted mere ghosts (not necessarily visible) or full-fledged apparitions (visible). If you feel you have a good answer that would necessarily render ghosts invisible, I'm listening.

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    $\begingroup$ Clarifications: Need not be permanently perceivable; need not be perceivable at all times (1 hour at midnight, say, is perfectly fine); need not be actually generating sound (but it's ok if it does); need not be the dead person; need not be summonable, but it would be cool if some pre-set 'ritual' 'called' it. $\endgroup$ Commented Jan 23, 2015 at 1:33
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    $\begingroup$ The more, the merrier, so feel free to answer, but I would try to go for a (futuristic, if need be) technological solution first. $\endgroup$ Commented Jan 23, 2015 at 1:43
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    $\begingroup$ The way Stargate did it was the next evolution of humans into pure energy beings, free from the tyranny of matter. Almost the same as Arthur C. Clarke where a species found a way to store their memories into the fabric of spacetime. $\endgroup$
    – tls
    Commented Jan 23, 2015 at 3:12
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    $\begingroup$ Not really an answer because it cant be done in our current universe, but they could bugs in a universe simulation. $\endgroup$
    – ArtOfCode
    Commented Jan 23, 2015 at 14:15
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    $\begingroup$ Note, that ghosts in Harry Potter have no connection to the afterlife. They are just an imprint, and are not controlled by the deceased from the afterlife. As afterlife in the Harry Potter Universe is strictly one-way, with no communication from there to the world of the living, from a technical point of view it's the same as if it didn't exist at all. $\endgroup$
    – vsz
    Commented Jan 23, 2015 at 22:46

18 Answers 18


All people using computer systems leave a trace of their activity. Often, this information tell a lot of important things about the personality of that person, and it could be easy for the deceased's loved ones to perceive this data as "alive", or it may just represent a way to still feel contact and have consolation for the loss.

Recently, I found this moving article that may be of some inspiration: Teenage son discovers his deceased father's ghost car in Xbox rally game

Well, when i was 4, my dad bought a trusty XBox. you know, the first, ruggedy, blocky one from 2001. we had tons and tons and tons of fun playing all kinds of games together - until he died, when i was just 6.
i couldnt touch that console for 10 years.
but once i did, i noticed something.
we used to play a racing game, Rally Sports Challenge. actually pretty awesome for the time it came.
and once i started meddling around... i found a GHOST.
you know, when a time race happens, that the fastest lap so far gets recorded as a ghost driver? yep, you guessed it - his ghost still rolls around the track today.
and so i played and played, and played, untill i was almost able to beat the ghost. until one day i got ahead of it, i surpassed it, and...
i stopped right in front of the finish line, just to ensure i wouldnt delete it.

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    $\begingroup$ reminds me of xkcd.com/686 $\endgroup$
    – AShelly
    Commented Jan 23, 2015 at 20:20
  • $\begingroup$ Reminds me of a certain Animal Crossing-related comic duelinganalogs.com/comic/… $\endgroup$ Commented Jan 25, 2015 at 23:11
  • $\begingroup$ Great story - technology was also used in the movie "I Robot" to allow the main character to talk with a deceased person's hologram AI - never had to consider the afterlife or why "ghosts" exist. $\endgroup$ Commented Jan 26, 2015 at 18:01
  • $\begingroup$ That's so sad :D +1 $\endgroup$
    – TrEs-2b
    Commented Jul 13, 2016 at 2:31

If you're looking for something that resembling a former human being but without there being an afterlife, then essentially you're talking about someone's imprinted consciousness remaining behind in some form.

Such a thing would have no physical manifestation (because it isn't a real thing, so to say) but could still be around because other minds or objects keep it going. I´m not sure what the tech level of your story is, but the higher it gets, the easier it becomes.

If we put the tech level slightly above where we are now, it becomes quite plausible. We´re already getting close, with Facebook pages for dead users that are still interacted with as an example. These people are gone, but their page lingers. If you go one step further and imagine a Facebook script that automatically replies to certain things, such as birthdays, you might get messages from dead people. In this case you still know the person is dead and you know what it is happening, but it's the first step. Any script that is smart enough to reproduce the kind of message the user would post will sound quite a bit like them.

If you make the internet a bit smarter, things get more eerie. Imagine you make a picture inside your late friends home, and the face-recognition software suddenly pings his face somewhere in the corner. Of course, the software is simply pretending to be smart; it's picked up that this is your friends' home, it found a "face" that it couldn't place, and suggested that considering where you are and that there's apparently someone there with you, it must be your friend.

Later on, the same kind of software might think that since your friend hasn't been talking to you in a while it will helpfully start a conversation between the two of you. Of course it's goal would be to kickstart it for a few lines before your actual friend takes over (both sides thinking the other initiated the conversation, ideally). It'll sound quite like your friend used to do, but sort of stops responding after exchanging a few platitudes.

Of course the above is just software, but imagine if the software has the same response to various other people the person knew, and they start talking to each other. Human communication being what it is, something like "I talked to John yesterday" will come up. Many people will not add in "through the computer", and will instead start thinking ghosts. (Remember; people already do this). But this time, they'll have a chat history to prove it, and it'll look pretty convincing.

People already use automation for a lot of common tasks and this will only expand in the future. At some point, if you die, you'll leave behind so many automated tasks, some of which are so hard to pinpoint as being automated (because if people realise it's automated, it becomes insincere, so they'll be as lifelike as possible) that it might easily be possible to get the feeling someone is still around.

You'll be able to 'interact' with them, they can make sounds, generate images and even control other devices. When you add in glitches and detection faults, it gets even creepier. (Imagine the door to your friends' house going open downstairs and hearing "Welcome, John" from the automated system. It just made a false positive and when you get downstairs there'll be nobody, but you'll still get a nagging suspicion)

As for putting the 'ghost' to rest; the solution would be to convince the world that this person is truly dead. This can be easy if there's a centralized register where someone's state is kept, but it can also be very difficult if various devices independently check whether or not someone is still around against each other, where the other devices automated interactions trigger the "still alive" for it, and it triggers the "still alive" for others.

Such ghosts could even become angry because the scripts are picking up that you're trying to convince the world their patron is dead, even though they think he isn't. They might react less friendly, decide that your friend's logical reaction would be to deny you access to their home and things, or even alert the authorities. They might even get the idea that you are trying to kill them and become openly hostile to you.

  • $\begingroup$ There was a fantastic episode of Black Mirror playing with a very similar idea. $\endgroup$
    – neminem
    Commented Jan 23, 2015 at 19:20

There are two ways (that I have considered) to have physical ghosts without an afterlife, both based on strange science I only half understand. They are both crazy, but don't involve computers.

  1. Parallel Universes. Parallel universes are basically (from what I understand of at least one theory) universes in which possibilities were played out differently than they were in our universe - every possibility since the beginning of time plays out results in an... abundant number of alternate universes. Those universes closest to us are the ones in which most possibilities played out the same, and only a few were different.

    In some of these universes a person will die, in another they live on. One could bleed through to the other, given that you can explain with some mumbo jumbo that death is a powerful event (due to the number of possibilities that end with a death, as well as energy, etc.). There are apparently a number of people who've already thought about this, though let me say here I'm not going to personally go on record and say that I think this is likely.

    Anyway, you could have a ghost bleeding through in an area where a person still lives there in a very similar universe, or maybe see a moment of death bleed through in a place where that possibility gets played out by that same person for every possible time that person could have died (the possibility of suicide makes this easy). But once again, all this "bleeding through to another universe" stuff makes me uncomfortable, but may work for your story. You could probably only kill this "ghost" by accessing an Parallel universe, or preventing the "bleed through" effect, whatever that is. Or just confront it and try to freak it out, seeing as it may be no less afraid of you than you are of it.

    My personal favorite type of ghost that could come from this is one I've often thought about after reading The Jolly Corner by Henry James, in which the protagonist confronts an alternate version of himself who ends up advancing upon him in rage. Perhaps these two persons both existed, each in his own universe, and each was mortified by seeing the other? This is my own personal favorite explanation of the story, and not far off from what James was going for.

  2. Residual energy (string theory, quantum mind). If you thought the last one was crazy, you may want to stop reading here. Given the supposed recent evidence for the quantum mind hypothesis, let us say that the mind operates above the regular scale of normal electrochemical processes - this involves quantum processes as you may have guessed from the name of the hypothesis.

    If the brain acts on a quantum level (this can actually play into the parallel universe idea; the position of quantum particles are a source of true randomness, leading to various possibilities within a quantum mind) then the energy left behind when a brain goes through a terrible freak-out death would probably be able to linger in some residual way (especially if you use phrases in your story like "string theory" which explain away all sorts of improbable phenomena, especially given how many different kinds of "string theory" there are) at least enough for some person to come along and detect said energy with their own brain (brains can detect each others' signals provided a means of communicaiton) and see the horrible freak-out death. Destroying a quantum ghost would probably involve... quantum mechanics? Or maybe an energy blast.


Imagine a virus, artificial in origin, created by geneticists as an espionage tool.

The virus has no physical symptoms and has a three phase life cycle.

In it's first phase it is airborne and contagious; searching for a host.

In the second phase it is non-contagious, quietly hiding with its host, performing its primary function.

In the third phase it is again contagious, but only by touch contact with objects handled by the previous host at their moment of death. In this third phase, the virus expresses its secondary function.

The primary function of the virus is to steal ideas. It slips past the blood/brain barrier and copies the host's genetically stored memories into an unused section of the virus's own genetic code. Strongly valued memories such as the faces of loved ones and those accomplishments which the host is most proud of, are reinforced within the virus by the same mechanism which reinforce suchmemories in the living mind. Having limited storage space within itself, the virus eventually only contains the hosts most valuable memories. Then it waits for the host to die.

Upon the host's death, the virus enters its third phase, spreading out into any objects which are in contact with the corpse, making them vectors for its once again contagious form.

The second function of the virus is to play back the stolen ideas. Once a person touches a contaminated object, the virus slowly enters them, again passing the blood/brain barrier, but this time to make a deposit rather than a withdrawal. New memories are inserted into the current moment consciousness of the new host, taking the form a indistinct sensations and half-glimpsed hallucinations. Lacking context and perhaps genetically encoded slight differently than natural memories in the new host's mind, images from the transferred memory might take on a spectral supernatural flavor. Knowledge and personality traits could also be transferred in this way, extending the illusion from that of perceiving a ghost, to one of being possessed by it as well.

Originally designed to steal the insights of the greatest scientists of the age, its accidental release into the general public might make real life mimic the best actions scenes from the original GhostBusters and/or Poltergeist.

Separate from this idea and each other, there are excellent scientific justifications for ghosts in both Dean Koontz's Phantoms and Piers Anthony's Shade of the Tree.

  • $\begingroup$ This is pretty clever. People are always dismissing the paranormal as mental issues: hallucinations, paranoia. But what if the new mental states are directed. Nice one. $\endgroup$ Commented Jan 24, 2015 at 4:05
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    $\begingroup$ Memories are not stored genetically. There's an awful lot that's not yet known/understood about how human-brain memory storage actually works, but enough of it that is known to pretty solidly rule that one out. However, maybe if the virus has some mechanism to read however the brain does store them, and translate that to encode it within its own genetics... $\endgroup$ Commented Jan 25, 2015 at 5:05
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    $\begingroup$ If by not stored genetically you mean that memories are not genetically inheritable, then I agree. If however you are ruling out all involvment of nucleaic acids in the task of memory storage, I would have to disagree. The OP requested a no-afterlife solution, which to me rules out our being anything more than our grey matter. Therefore any memories we have, must be stored somewhere in that grey matter, where a virus could get at them. As world builders we often have to fictionally answer questions which science leave open. Otherwise we can't do our jobs. $\endgroup$ Commented Jan 25, 2015 at 18:24

If they only have to interact with people, an idea can suffice.

Consider an idea like an earworm (that cursed song someone hummed on your way into work and now it's stuck in your head). If there was a viral idea that was constantly distributing itself through a society, it might manifest in apparitions because it's the easiest way to keep itself going. That manifestation would be a ghost, and a symptom of a much larger idea spreading undetected.

The advantage of being an idea is that you're already past someone's eyes and ears, so its trivial to make hallucinations. The interesting part is syncing the hallucinations up between multiple people so they see the same thing. This isn't impossible with subtle communication via. body language, but it does mean that one person shouting "you're not real! you're not real!" can really disrupt a ghost.

Then again, there's no reason they couldn't also have some whisp of a form outside of our heads. Those would be the scary ones that you shout "you're not real!" and it just doesn't seem to help quite as much.

  • $\begingroup$ Thats some SCP right there. $\endgroup$ Commented Jan 23, 2015 at 2:57
  • $\begingroup$ I think the correct term for that is an "earworm". An earwig is an actual arthropod. $\endgroup$
    – March Ho
    Commented Jan 23, 2015 at 9:01
  • $\begingroup$ @MarchHo: Eep! Thank you! Edited. $\endgroup$
    – Cort Ammon
    Commented Jan 23, 2015 at 15:43

You could use ancestor simulation as a precept with multiple iterations of the same or similar simulations being run on the same ancestor simulator? Computer hard disks tend to be overwritten rather than erased - you could make this presumption of the storage or processing medium that an ancestor simulation is run on. It wouldn't be too much of a jump to make people, things and places persist in a diminished way using this as a device.

Immaterial but visible could be handled by them not being included in the current simulation therefore collision detection between them and currently simulated objects does not function etc.

They would be copies of people used in a previous simulation therefore could be copies of people dead in the current simulation but who were also in the previous one. This could also give them precognition if a simulation of a period was being re-run multiple times. It could also be copies of the same person.

They could be killed by processes in the simulation which look out for artefacts from previous simulations and delete them. Garbage collection. Therefore, if they are aware of their status then they may be afraid of being noticed or referred to, photographed etc as this may draw the attention of the garbage collection processes. Oh dear it's all gone a bit matrixy!


TL;DR: Artificial projections based on a life's worth of digital content, partial uploading, coupled with a trigger mechanism and a durable power supply.

Uploading never worked. It turned out that creating a new memory-association-chain in a human brain involved a holistic effort by the entire brain, and the complexity of the process defeated the best human minds for centuries on end. All it did manage to create was an abomination, a sad simile, incapable of true consciousness, of genuinely remembering new experiences, or of adapting to new environments. A failure.

With time, a new practice evolved, of decorating the crypts, cemeteries and cities of the dead with these magnetic-force-field enhanced holographic projections of those no longer living, based on such partial uploads. Some were only triggered by specific actions, such as placing flowers in a particular vase in the crypt, or rippling the water in a still, crystal-clear pool, while some only activated on the anniversary of their death. The varieties were endless.

As this became more accepted, and the projections were no longer seen as abominations, the practice grew in scope. After the massive blast that took out the Andromeda Gateway and the surrounding great city of Carston, surviving friends and relatives recreated a distorted, slowly evolving projected replica of the entire city and its millions of inhabitants from records of the town and of the people, all on top of the overgrown ruins. As a monument.

On the fierce battlefields of the future, people's life-recorders sometimes survived the blast that killed their owners, and, left on the desolate and temporarily radioactive wastelands, the life-recorders triggered and released a sad and confused ghost, forever retracing their last steps and random fragments of their life. Those with ZPE power-plates had a lifetime measured in tens of millennia.

Slowly, as the gap between those embracing technology and those that didn't grew, the daring, the curious, the brave and the restless grew weary of Earth and embarked in great journeys across space, leaving behinds an ever-more conservative, ever regressing Earth. The long elevators were torn off their sockets and cast out into space. Things that were once known, were forgotten. The great underground oil, coal and mineral manufacturers trudged on for millenia, undoing the depleting work of many centuries and creating new resources for a new dawn. Eventually even these great machines froze in their tunnels.

The ghosts, however, lived on amid the crypts and ruins of those majestic towns of an age long forgotten.


One option is akin to Solaris "copies".

In short, the ghost is a production of one or more of the viewers.

Create some kind of "plasma" that somehow reacts to memories of people around it. Of course, it cannot react to all memories of all people; so make it that they react to memories of certain people, or who are in a particular emotional state.

Of course, being materializations of something as subjective as memories, they are subjective themselves. If the source of the memory thought the "original" was a jerk, the memory will reflect that. If the source thought it was a good man, then the materialization of the same "original" would be (and act) different.

Note that all of this would not be the result of a voluntary act; the source of the memory may think that he is not who is projecting the ghost.

One point is is the ghosts are interactive, or they just show the person/event as if it was a recording. If they were interactive, either the source of the memory has to witness the attempt of interaction (and then, unconsciously, think what the original person would do in the situation), or the "plasma" can communicate telepatically to transmit that information to the source.

To "kill" the ghost, you could either knock the source of the memory unconscious (because it has been proven that unconscious people no longer are in the distressed state that allows for the projections), give him a drug (with or without side effects) or have a device that generates EM noise in the frequencies used by the plasma to read the source's mind.


So, by your definition, you want not just a Ghost, but an Apparition: a Ghost with visible, recognizable humanlike presence.

The XBox story was my first thought, too.

This could indeed be a virtual one, a recording of them as in the XBox story, or even an AI, a learning system that has acquired their skills and behaviors at least in the very specific domain in which it is designed to learn.

In the XBox case, rather than merely driving like they drove on their last lap, a learning system could drive like the drove on average, displaying random of their driving quirks; or could drive as they did at their best on each stage of the race, thus driving better in sum than they ever did in life.

A recorded video of someone, projected, would also work. If holograms are possible, then you have the Star Wars "Help me, Obi Wan Kenobe, you are my only hope!" - a ghost of a living person perhaps. Otherwise, you can project onto a wall, or more mysteriously, a stream of smoke, mist, cloud, or water. Could also be a computer-generated sprite texture-mapped with the person's face. Particularly with a low-fidelity projection onto a vague mist, the computer-generatedness would not be so apparent.

But there are other ways to record a person's passing. Perhaps, as they walked from a clearing, they swiped at the thick leaves, and in doing so, either deliberately or accidentally hacked out a person-shaped hole, which, when the sun sets in the evening and shines through it, illuminates the spray from the waterfall. Doesn't even have to be a hole anyone's hacked out - but more likely if done as a deliberate thing. Since the sun moves slowly, you could have it so that only when the light from the sun lit a crystal at a certain angle, it refracted to become a projector - that way you could limit it only to a few minutes, or even a few seconds.

One effect I've seen that caused much consternation was headlights over a hill, which, because of the angle of the road, would shine in the back of a ruined house: the house would look lived in, for a moment, and then would fall dark again as the car moved on. Headlights on hilltops have also caused any number of UFO sightings. So, they make good brief-unexplained-lightings. If a picture is briefly lit by headlights passing outside, and the figure in it appears to because the shadows cast on the picture move, that could be a convincing "ghost" effect. Lightning could have a similar effect.

Another good effect is a moon-halo. Here's a good trick. When the moon is close to full and dew lies upon the grass, look at your shadow: you will be surrounded by a halo. Tell your friend "Wow, there's a halo around your shadow!" (as if you see the halo around his shadow, and not your own) and the odds of him thinking there's something mystical about himself are quite high. When you stand above a mist-covered valley, and your shadow is cast onto the mists below, that has the same effect, writ large. So in this way, someone could be convinced into thinking they see, perhaps, their own ghost, or at least an outline, with a glow from their spirit?

Double-exposure is possible, too: taking shots with a film exposed some years ago that you did not know had already been used to shoot someone else, would show them as ghosts in the shots. Similarly for a videotape with an erase/record head that did not fully wipe the previous data, perhaps.

For more modern digital tech, it would take some kind of software bug - or a virus/malware/joke app that would impose another character into existing video.

In realtime, augmented reality apps like google goggles or yelp's equivalent, let you point your phone at things and see signs for places nearby, etc... what is there was software on your phone that meant, when you pointed your phone camera at something, you say your dead friend superimposed in the shot, or perhaps just their face overlaid over nearby faces that the camera software identified?


I should preface this with I'm not sure how much I fully accept/believe this...it's taking two philosophical theories, mashing them, and coming up with what could be a ghost. Fun anyway.

If a tree falls and nobody is there to hear it, does it make a sound? My answer is no (the only exception to this fits in to the 'human-centric frame, why can't the tree observe and hear itself falling?). Without an observer the observed does not exist. This answer finds it's root's in the same theory that brings about Schrodingers cat, ultimately the observer and observed are inherently linked and cannot be separated. For example, the monitor infront of you is nothing more than a blob of matter...electrons, protons, neutrons,and a whole wide array of -rons that are quite meaningless to themselves. It is you infront of the monitor that brings them meaning, forming them into words and understanding. Two eggs on a plate with bacon can form a smiley face that you see...who says that smiley face you see is any less real than the eggs on the plate? Everything exists as a multitude of possibilities and your choice to observe it collapses it into one.

The second portion of this is our shared reality. Your observation of something collapses it into a single possibility not just for you, but for me and any other observer as well. Alternate wording...you insisting that something is what it is, shapes what it is for me. It's an interesting discussion to have, and hints towards us being all fragments of the same consciousness...just take the summary of your observation can/will affect others observation

If you can accept the two theories above, this does leave room for 'ghosts' as persistent interpretations...observation points that are so strong that others (you and me) can still perceive them. Left overs of past observers if you will.

SO to your points...persistent observations:

  1. It's perceivable to multiple people in that anyone that can perceive someone else's observation can perceive it (inability to perceive others interpretation is generally referred to as psychopathic / extreme narcissism)...so most of us. Each of us could perceive the persistent observation differently to some degree.
  2. Immaterial in that they are observations, not physical
  3. The persistent observation would resemble whatever someone last observed it to be...if it was a human leaving it behind, odds are it'd resemble something human. Hard to say interactive, but if it's a left behind observation point, a lot can be learned about a person from that...afterall what are we beyond what and how we observe and perceive?
  4. Can't think of anything stronger and more likely to leave behind a persistent interpretation than life/death...maybe extreme repetition?
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    $\begingroup$ +1. Reading "Trespassing on Einstein's Lawn" at the moment. Have the feeling you'd love that book. $\endgroup$ Commented Jan 28, 2015 at 0:41
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    $\begingroup$ @SerbanTanasa I'll add that to the reading list. In writing, I like the variability this introduces from person to person and their ability to perceive these persistent interpretations. A more stubborn 'physical is physical and what I see is the only thing that can be' style person would be relatively unable to perceive anything but the strongest persistent interpretations. An open minded person more capable of seeing more interpretations points would be more susceptible to seeing these...so a character might be completely capable of interacting with what another character can't perceive. $\endgroup$
    – Twelfth
    Commented Jan 28, 2015 at 0:59

I don't understand why you want the ghosts to represent a formerly living person if you're so against the afterlife idea. That doesn't make sense to me. Regardless, I have two ideas.

  1. Technology can make this happen easily. You can program your perception of a [dead] person's personality into some kind of device that uses that information and a physical picture/description of the person to create an interactive hologram. I think that's boring, though. (To kill it, turn the power off.)

  2. I've always built stories off the idea that a person is comprised of four parts: the heart (emotions), the mind (logical functions), the body (duh), and the soul (beliefs). If this were true, then the body would be simply a physical vessel for the other three. So its possible, then, that you could separate the body from the others but not necessarily the others from one another. When you remove the body, what is left is your "ghost". It can have whatever appearance you (the author) wish, its intangible, it retains the logical functions of the person and can therefore determine it is a ghost, and the means of separation could be killing the body if you so wish. Given that you have creative license, you can say that the longer the ghost is separate from the body, the fuzzier its memories are. And as for killing it, any typical ghost removal methods could apply -- burn the remains, exorcism, vacuum.

  • $\begingroup$ I need not be against it. Just consider death to be an event horizon of sorts. $\endgroup$ Commented Jan 23, 2015 at 23:55

The classic case of this would be the "Ghost in the Machine". An uploaded consciousness (or an AI based on a human) that exists in the internet and expresses itself into the real world from there.


It could easily be a thing the characters have a superstition or religion about, but has a technological foundation they do not understand. This gives you a lot of options. That can either be part of the plot or simply something you know yourself as the author and permit to influence the way you frame events according to the rules of the world. It can also be something that the characters are aware of, only some of them are aware of, something they are oblivious to, or something they have a revelation about later on.

In my opinion the unseating of superstition, having it turn out to be something that is actually understandable once some hurdle is overcome, is a powerful storytelling device.


The possibilities are endless, i'm fond of mass hysteria since it's probably accurate. In that case the ghost is just a shared delusion created by the suggestion that it exists and being reinforced by confirmation bias. That might not seem to immediately meet your terms, however to those experiencing the shared delusion they would perceive it by attributing coincidental happenings and noises to the "ghost". For example: "Did you hear that?", "Yes, it was definitely screaming and not the wind".

Immaterial? Imaginary things often are.

Resemble a formerly living person? It can look and act like anything those experiencing it would like. More likely though if it did appear visibly it would be evidence of a more serious mental illness and not just a trivial trick of the mind.

Killing it off? No problem, just forget about it.

  • $\begingroup$ How M. Night Shyamalan of you. $\endgroup$ Commented Jan 23, 2015 at 23:20

Excluding using technology as your explanation since that is covered in so many other answers, you could develop a shapeshifter type of creature similar to the Clutterbumphs in Manxmouse or the Bogarts from Harry Potter. Basically, have an ethereal being (either through magic or some other means that fits in your world) that has no form of it's own and in order to manifest itself it must resemble the form of something else. Perhaps these creatures have the intent of being scary (like bogarts and clutterbumphs), or perhaps they are creatures of overwhelming sympathy that are attracted to people in mourning, etc. Perhaps they steal the image of whatever they are looking like and if someone were to inspect the corpse of whoever's image they stole, they'd find that corpse to be remarkably featureless. That's my 2 cents in any case. They are NOT the ghost (as we know it) of the thing they look like, they are themselves, but are simply formless until they can borrow the form of someone else.


One of my favorite author's did this with a really neat AU:


The basic idea is that a ghost is the electric/magnetic record of human consciousness. Sometimes violent deaths leave that record imprinted on an area, resulting in a visible - but intangible - ghost. There are variations where some ghosts are more "aware" than others, but most just replay specific events.

He takes some other interesting turns with the story - in his world zombies are basically humans minus their "ghost" portion, they act kind of like automatons with no free will. Significant parts of the story revolve around ghost-tech - the ability to store, erase, or project ghosts (and this can also be used to zombify humans).


This is similar to what JackArbiter said in part 1 of his answer about parallel universes, but the idea of a rift of some kind between dimensions. http://en.wikipedia.org/wiki/Interdimensional_being

What comes to mind is the old Star Trek TOS episode "The Tholian Web," where Kirk gets stuck in an "interdimensional rift." They think he is dead, and several characters see him as a ghostly apparition during the episode. http://en.wikipedia.org/wiki/The_Tholian_Web

No religion, mysticism, or afterlife, just good ol' scientifically-questionable Star Trek.

To expel the "ghost," you could heal the rift in some way, or it could naturally dissipate.


Here's how I do it.

Imagine a cube, there are 3 "levels" in it. Your cube is your universe. This cube is spliced by these 3 "levels" this way: Height (top to bottom) Width (left to right) Length (front to back)

The "height" is what I call "plane" (or "planes of existence") The "width" is what I call "parallel" (or "parallel worlds") The "length" is what I call "dimension" (or "different dimensions")

The differences are these: Dimension = example, if your character travelled to the other dimension, he may find that the nucleus contains a neutron and electron, and the one revolving around is a positron. Different from his origin dimension (our dimension).

Parallel = example, if your character moved to another parallel, he may end up in a world wherein humanity evolved from reptilians not monkeys

Plane = ahh, now the sweet part. The "ghosts" that your characters are seeing are actually from a different plane than the plane your characters are in (currently). So say, someone from a "higher" (or "lower" if you prefer; this is just base on the cube analogy above), may show in his plane, and vice versa.

Combine these 3, you get something like this.

Character-A watched how Ghost-B opens the door to his room, then disappeared leaving the door opened. What happened was this, Ghost-B is residing on the same dimension and parallel as Character-A except that Ghost-B is on a different plane. It could be that some unexplained mystery of the universe interacted at that moment to make Ghost-B's action on his plane of existence affected the plane of Character-A.

Now, if Ghost-B is on a different dimension or a different parallel, Character-A won't see Ghost-B at all.

Then you can play around this setup, endless possibilities -- but is a headache at first.

I'll leave the "explanation" of how and why "parallel", "dimension", and "plane" are actually 3 different realities of the multiverse.



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