Much like a proverbial Kool-Aid Man, ghosts are often depicted showing little regard for the intra-structural boundaries you and I take for granted, going through walls with absolute abandon. You can barely broach the subject of spirits without one proclaiming proudly that such beings are not bound to the typical laws of collision observed by physical entities like ourselves. This I find to be a curious characteristic of the reputation ghasts have garnered.
An example known to many the world over is the boo from the Mario series. In most iterations, they pass directly through solid walls without resistance. (This can be particularly annoying in Luigi’s Mansion, where they will flee to another room and hide.) And if you’ve ever seen the Netflix series Lockwood & Co, (would recommend, by the way) you’ve witnessed this behaviour on full display.
Why is it that ghosts in fiction are consistently known for this behaviour? How could such a thing even be possible? Would it make sense for an actual ghost, if such a thing exists, to do the same? Well, I’m not an expert on ghosts, (not that anyone can be with the evidence we have at present) but I think I might be able to explain this feature of fictional ghosts, and how it relates to real reports. I’m going to present several theories as to why ghosts go through walls.
#1. Alternate Matter
You might have seen the movie Spectral. Even if you haven’t, you’ve probably seen Ghostbusters. If so, you’re probably familiar with the idea of ghosts being made of some kind of energy or material that doesn’t play by the ordinary rules of physics. Just as dark matter is theorized to pass through matter and even itself, this type of ghost is simply not tangible in the conventional sense.
While currently relegated to science fiction, an entity formed of a substance quite unlike normal matter is actually fairly plausible from a hypothetical perspective, although there is no evidence to suppose that such a thing exists in this universe. Does this concept of a ghost explain where conventional hauntings and reports of paranormal activity come from? No, it probably doesn’t, as this is more than a little far-fetched, although it is definitely fun to think about. If something like this does exist, discovering it could significantly further our understanding of physics.
How would such an entity operate? Well, material organisms run on chemical energy. They intake some combination of exogenous radiation and matter, which is then processed as a fuel source to maintain vital functions. Perhaps such a creature would intake some form of energy unknown to modern science, or could interact with ordinary radiation and matter in some capacity. This could fuel its activity, allowing it to startle mere mortals with its signature nonobservance of physical barriers.
Depending on exactly how it functions, it may be capable of interacting with physical objects in some capacity, and it’s not unreasonable to suggest that such an entity would be invisible. Perhaps it could become visible at will by emitting light radiation, or through some similar means. It may or may not be capable of directly harming human beings, and perhaps some emission of the creature, such as infrasound, could cause psychological harm to humans.
This would account for most features of ghost reports, and is technically possible from our current understanding of science. Definitely a good angle to consider for science-fiction, but I’m quite skeptical that this is the culprit behind any real hauntings.
#2. Ethereal Plane
If you’re familiar with D&D, then you might know about the ethereal plane. By shifting to the æther, ghosts in the D&D multiverse are capable of becoming translucent or invisible, and can pass through most solid matter. They can float through the air, as gravity simply does not apply there. This also makes them resistant or immune to most physical attacks, making a ghost a dangerous foe to encounter at low levels. However, spells and magic weapons can make this significantly easier, depending on the edition in question. (Ever heard of eldritch blast?)
Lord Of The Rings has a similar concept, with both the army of ghosts and the Ringwraiths. The former were certainly ghostlike, with mortal weapons having no effect on them. The latter invoke an interesting concept in the Middle Earth mythos, as they exist in something of an ethereal state. Whenever a mortal dons the Ring of Power, he appears to become invisible to other mortals. (Although, interestingly enough, he still casts a shadow.) This is due to the wearer becoming ethereal, in some sense. Because the Ringwraiths and Sauron already possess an ethereal nature, they actually find it easier to locate the wearer, not harder. Like most topics related to Tolkien, it’s more complicated than I can do justice here, but I think I’ve covered the basics. This is very much like an ethereal plane in other works, except for the lack of intangibility, and it probably inspired D&D to no small extent.
There is also something of an equivalent in physics, I suppose. The concept of higher dimensions is often used as a basis for positing the existence of interdimensional beings. This is proposed to explain UAPs and paranormal activity. While there is very little to substantiate such theories at this time, it can hardly be ruled out as a matter of course. We learn new things all the time, so it is definitely possible for something like this to exist, even if it’s far from likely. I suppose we’ll just need to keep an open mind on the off-chance that Keel was right.
#3. Echoes Of The Past
An interesting idea of ghosts is that they are but a fading memory of what once had life, reenacting the deeds of their past selves. Particularly prominent might be the last moments of their lives. Ghosts of such a nature were featured in Supernatural, though other varieties of ghostly entities appear there as well. This kind of ghost is potentially more sad than scary, as they go through the motions of repeating their personal tragedies rather than making any deliberate effort to harm the living.
If a ghost is much like a hologram on loop, cycling through the event of its death whenever it manifests itself, it could certainly make sense for it to disregard whatever walls have been constructed in the meantime. A spirit might walk the very same path it had decades before, even if the house had been remodelled since. It is worth making the distinction between ghosts that are capable of recognizing their surroundings, and those that cannot.
Real-world hauntings are often ascribed similar qualities, with some connection to the actions of deceased individuals. Ghostly figures are often reported walking in the places they frequented in life, sometimes even engaging in the same pastimes. It begs the question of whether ghosts are really intelligent beings at all, or just some form of memory we don’t yet understand.
#4. Unseen Realm
Considering that ghosts are widely believed to be supernatural agents, it would make sense for a non-material explanation to come up in the discussion. Well, suppose that an intelligent supernatural being could interact with the waking world in some way, probably by means of illusion or projected hallucination. This is similar to the interdimensional hypothesis, although its basis is not in fringe physics, but forgotten fables.
Mankind has always postulated the existence of spiritual entities, ranging from powers that rule over the mortal realm to lesser spirits that may haunt the living. There’s even the idea that they may originate from dead people. In any case, I think we can agree that if some entity exists in the realm of the mind, and can influence human perception, then I see no reason why the hallucinations inflicted upon the living need heed the boundaries of blueprints and the arbitrations of architects. An imagined figure appearing from or disappearing into a wall seems perfectly concordant with this idea.
This concept is certainly well-suited for adaptation to urban fantasy. It has a rich background in mythology and folklore, and it seems entirely plausible for such a thing to exist without the world-at-large knowing about it. So plausible, in fact, that it just might be true.
#5. Not Real
It would be remiss of me to go without mentioning the obvious. Given that there isn’t much hard evidence that paranormal activity is anything but an aberration of the human mind, most mainstream scientists regard the real existence of ghosts as unlikely.
In a fictional context, an accurate representation of physics is typically considered unnecessary so long as the work is sufficiently entertaining. No matter how implausible it may be for a ghost to travel through walls, if it makes for an interesting show, someone is liable to write it. The idea of ghosts as selectively tangible is something easy for humans to say, even if we don’t have any way of proposing how it could exist in the real world. One could make a serious argument that complex explanations of monsters and magic in fiction is nothing more than a form of wish fulfillment. We find the idea of these things cool, so we try to make it sound as plausible as we can to maintain the suspension of disbelief.
While I don’t think anyone has yet to prove that ghosts don’t exist in any capacity, it does seem very likely that the majority of lore surrounding ghosts has little basis in reality. There are many factors that can cause people to experience phenomena subjectively interpreted as a ghostly presence, especially when actively searching for anomalous stimuli. There certainly may be some truth to ghosts, but I think many people need to take a step back and honestly evaluate the evidence at hand.
I just spent hours postulating hypothetical reasons why ghosts may be able to go through walls, and you likely just spent several minutes reading them. You may very well be asking what would possess me to do such a thing. Well, I think it’s important that we take a closer look at things we often take for granted. Maybe fictional ghosts aren’t the most important topic in the world, and perhaps it doesn’t do much for the state of paranormal research, but I still think it’s worth talking about. Fiction is an extension of ourselves, our thoughts, our desires. Humans have been telling stories for about as long as they’ve been breathing. It’s just something we do. And I think that if we better understand these stories, we better understand ourselves.
It’s fascinating to me how so many people can agree on the idea that ghosts can go through walls, despite the fact no one agrees on whether or not they even exist, let alone how to explain them. With this exploration of creative media, I hope I’ve done something to expand your mind. Maybe you’ll pay more attention next time you see a ghost on a TV show. Maybe you’ll think about the scientific plausibility of a spectral figure interacting with matter selectively. Or maybe you’ll just turn your brain off and spend the rest of your days as a mindless consumer devoid of any critical thinking and artistic engagement.
Either way, I think there’s something very profound about the way we perceive fantastical entities. Even if ghosts aren’t really here, at least they’re with us in spirit.