Can Ghosts Exist?

A Halloween-themed exploration of the (pseudo)science of ghosts.

Posted Oct 14, 2019

In the spirit of Halloween season, for this post, I thought I’d look at the science of ghosts and how we might reasonably test whether they exist or not. Surveys suggest roughly half of Americans believe in ghosts with a substantial minority saying they’ve actually seen or interacted with one. Such beliefs may be more prevalent among some ethnic groups such as Latinos or among the more religious (oddly enough since ghosts aren’t technically part of the Christian faith). But is there any scientific data to suggest ghosts exist? 

Let’s dispense with the obvious: No, they don’t exist, and there’s no good reason they should. In fact, there are a number of explanations for phantom phenomena that are entirely mundane. For example, magnetic fields or other normal sources may cause unexpected sensory stimuli people misinterpret as the supernatural. But it would be boring for the surprise twist of Haunting of Hill House that the horrors to turn out to have been due sonic vibrations caused by nearby traffic on the interstate. So, let’s dispense with the rational, put on our tinfoil hats and have some fun.

I’ll confess, I really want ghosts to exist. Simply because I love Halloween and it would be so cool if they did (plus there’s that eternal soul thing so I guess ghosts would be a good sign.) But for all people’s beliefs in them, it’s hard to imagine why they would or could exist. They can’t be supernatural, so ghosts would have to be part of the natural world and subject to natural laws. To test them empirically, we’d need a theory of ghosts that we don’t really have. So, for kicks, I’m going to try to devise one.

I love those old ghost movies from the 70s and 80s where the family experiencing a haunting go to the nearby university and find the Department of Parapsychology as if universities treated this as seriously as, say, Chemistry. To be fair, in the 20th century some parapsychology labs did exist, one of the most famous of which was at Duke. And scholars did try to employ modern experimental methods, particularly when examining phenomena like ESP (reading minds, foretelling the future, etc.). Indeed, some scholars have argued that the effect sizes (magnitude of effect) for ESP is pretty similar to other findings in social psychology. This is probably true, although I’d argue this is less a defense of ESP as an idea, and more an illustration of how much of mundane psychological research is likely rubbish “noise” rather than true effects. But I digress. With all the attention on ESP, ghosts seemed to get short shrift.

So, in thinking of a theory of ghosts, let’s allow one big assumption: that souls exist. Yes, yes, I know—this is, to say the least, a pretty big assumption from the scientific perspective, but let’s allow it. This does require us to sketch out some kind of quasi-scientific theory of souls. We might imagine that the universe has not only matter and energy, but a third element which, in the spirit of catchy names, we’ll call soul-stuff. Soul-stuff we can think of as a kind of raw consciousness. Jung’s concept of the collective unconscious may be vaguely analogous, although turning to psychoanalysis for scientific support is a bit of a losing game. 

We might imagine consciousness exists and, in a simple Cartesian sense, we can observe it since we can detect it within ourselves. Sure, we can’t detect or measure it directly outside of ourselves which is a teensy weensy problem for science, but we’ll say we can infer it in the behavior of others. If this soul-stuff fuels consciousness, then it must exist in the natural world (though we haven’t developed tools to detect it directly) and is subject to its own set of natural laws.  Presumably, certain combinations of matter and energy as typified by neurons are capable of capturing soul-stuff, creating consciousness in living things. So, humans aren’t particularly special, other than having fairly sophisticated nervous systems compared to jellyfish or prawns. Plants, not having nervous systems, should have no consciousness. Bad news for all those who have wasted time talking to their plants to cheer them up. 

Upon death, presumably, this soul-stuff returns from whence it came. Whether we retain any identity past this point or our consciousness becomes like grains of sand on the beach is beyond even this highly speculative noodling on consciousness.

Sure, none of this is falsifiable, but bah, it’s Halloween and we’re having fun. But now let’s see if, allowing for the presence of a soul, ghosts make sense. Why would souls stick around after death instead of going on to their eternal reward? If certain combinations of matter and energy, such as found in neurons, are necessary to capture consciousness, why are blobs of consciousness sticking around in somebody’s attic? Why do they always seem to wear clothes? Surely, clothes don’t have consciousness? Can’t ghosts at least keep up with the latest fashions?

Obviously, even if we generously allow for souls to exist, ghosts still seem implausible. If we look to folk culture, particularly in the West, we can see some common threads such as that:

  1. Ghosts are often the product of tragedy such as homicide or suicide.
  2. Some ghosts seem to have some task they never completed in life.  Just what’s so important (never finished that novel, trying to find out how How to Get Away With Murder wraps up, etc.) isn’t always clear.
  3. Sometimes dead relatives show up, because 70-80 years of nagging in real life just aren’t quite enough, and:
  4. Ghosts are mysterious, spending enormous amounts of thought and energy hinting about what they want to say rather than just saying it.

This ignores poltergeists, which are thought to emanate from troubled living persons (and oh did that movie not age well ... and parents smoking pot in the home got a PG rating, how things change). I’m also not impressed with these ghost hunter shows where a bunch of doofuses run around with random gizmos pretending to panic at every creaking board in an old house. If ghosts exist, they need to follow natural laws. That means a lot of ghost story tropes can’t work. My favorite is the eerie voice that no one can hear in real life, but people can hear on a recording played back. Can’t happen. Noise is vibrations in the air…if a recording device picks it up, so can the people recording it, unless they’re deaf.  Besides, why would ghosts even do this? A ghost talking to me in real life is spooky enough … they’re not going to impress me more by making me work listening to it on some old tape machine (naturally requiring me to listen and rewind, listen and rewind with an ever-increasing expression of concern on my face).

The non-poltergeist phenomena appear to be divided among phantasms and actual ghosts.  Phantasms are more like recordings than they are consciousness. An event is played out like a movie but doesn’t interact with the viewers and has no actual awareness. Actually, this version of apparition makes a bit more sense (and keep in mind I’m talking relatively here), as we could theorize that an emotional event (like a homicide or suicide) could leave some kind of after-image on the surrounding matter. Add in a battery-like energy source, such as susceptible warm humans walking nearby and voila, you have your specter. Presumably, the right physical space could hold onto small amounts of consciousness required to play the “film” which is activated by the energy the viewers themselves bring (absorption of that energy creating the commonly reported feeling of cold experienced in the presence of an apparition). I have a sense some elements of this might even be testable, believe it or not, through comparisons of matched sites where people died tragically versus naturally. 

Ghosts themselves, actual intact blobs of consciousness that stay rooted to a spot or visit relatives’ homes after death are more difficult to conceive of in practical terms. These would seem to need to violate even the whimsical natural laws we’d assume were in place for soul-stuff. What would allow an identity to remain intact and present in a particular space, despite being separated from the physical apparatus of neurons required to capture it in the first place? And why are they always so coy, particularly with mediums? They’re always like, “Tell Susan, M. is here, and I was an important man in her life,” instead of “Hey, this Susan’s dad. Can you let her know she’s forgotten to feed my fish for the last week?”    

Alright so maybe souls are incentivized to stick it out because something really bad happened.  Why spend decades ratting pipes, hovering over people’s beds and chasing them through the halls rather than leaving a polite note in ectoplasm or whatever?  Maybe, “Dear New Occupant: I’m buried in the basement. Might want to alert someone. Cheers, Cliff.”

Indeed, I can come up with a theory of souls, fanciful as it may be, and even phantasms. But even if it’s possible for certain spaces to kind of roughly capture soul-stuff, the kind of energy drain that would be required to hold onto a soul semi-permanently for a haunting seems difficult to comprehend. I’m not saying nuclear power plant level, sure, but given the crappy physical structure of a house compared to a brain, presumably, the energy input would need to be considerable. So too it’s difficult to imagine how my dad could catch the 5:15 from Heaven to Orlando in order to pop in for a chat.  Most such experiences with deceased loved ones appear to be related to intense feelings of grief, so more plausible theories of such phenomenon aren’t difficult to imagine. 

Ultimately, the best I can imagine is that hauntings would need a physical space that is compact and benefits from some kind of continual background energy source to “save” the ghost, like on a hard drive. As with phantasms, perhaps the presence of live humans provides an additional energy boost to allow for a manifestation. Something like a tragic death could provide an initial burst of energy to get the ball rolling, as it were.  In that sense, perhaps the one thing those ghost hunters may be onto is that temperature readings might be one empirical way to tests some hypotheses related to ghosts. Yet to say all this is speculative nonsense, is to do a disservice to speculative nonsense everywhere. 

Still, wouldn’t it be so cool if there actually were ghosts? If we could agree on something like a coherent theory of ghosts we might actually be able to empirically test at very least specific assumptions about how they might exist. If you’ve got better ideas than mine (and you might, or otherwise you might just be nuts) feel free to leave them in the comments (and yes, I know I’m inviting all kinds of chaos). In the meantime, let’s take off our tinfoil hats and rejoin the sane world. Maybe Halloween won’t bring us ghosts but at least it will bring us candy!

If you liked this post, be sure to check out my forthcoming book, How Madness Shaped History. No ghosts, I’m afraid, but plenty of mayhem and a few surprises related to the upcoming U.S. election.