The Curious Question of Ghost Taxonomy

Benjamin Radford

Among the vast constellation of unexplained and Fortean topics, ghosts are by far the most elusive and unknown. Cryptozoologists who search for Bigfoot, for example, have reached a general consensus on what they’re looking for: a tall, bipedal, hairy, manlike animal. Not so with the most popular paranormal subject in the world: ghosts.

What are ghost hunters looking for? It’s not clear. As Owen Davies notes in his book The Haunted: A Social History of Ghosts, historically “Ghosts shared certain characteristics with fairies, angels, and devils, and the tricky task of distinguishing between them often depended on the context in which they appeared: and this in turn changed over the centuries according to religious, philosophical, and scientific developments” (Davies 2007, 13).

Over the years various attempts have been made to classify and categorize ghosts (by early researchers including G.N.M. Tyrrell, Eleanor Sidgwick, and others associated with the Society for Psychical Research and more recently by writers such as Brad Steiger and John Zaffis) usually according to eyewitness reports. Of course there are inherent problems with classifying and categorizing potentially ambiguous and error-prone experiences. This was perhaps not obvious in the late 1800s, but over the past decades, it’s become clear from psychology research that sincere people misperceive and misremember events with alarming consistency. Research is only as good as the data, and the testimony and accounts of apparition witnesses simply cannot be taken at face value.

There are a half dozen or so different definitions of ghosts, and there’s equal evidence for all of them. Trying to classify inherently unknown entities whose very existence and nature remains unproven is a fool’s errand: How many types of ghosts are there? As many as you want there to be.

Many ghost-hunting books begin by boldly asserting that there are a specific number of types of ghosts (curiously the exact number varies somewhat, from two to a half dozen or so). For example, Rich Newman, in his 2011 book Ghost Hunting for Beginners, claims that there are three types of hauntings (he offers no source or reference for this, essentially offering a version of “they say …”).

But the simple fact is that no one knows for sure whether ghosts exist, and therefore no one can be sure how many types of ghosts there are. Ghost reports and sightings can of course be catalogued, analyzed, and categorized, but ghosts themselves cannot. This is a basic mistake, confusing a type of ghost for a type of ghost report; they are not the same thing at all, and ghost hunters confuse the two at their peril. A ghost report is merely a record of something that someone—for whatever reason and under whatever circumstances—could not explain and chose to attribute to an unseen spirit and may or may not reflect an actual ghost appearance.

When sociologist Dennis Waskul and his wife interviewed ghost experiencers for their book Ghostly Encounters: The Hauntings of Everyday Life, they found:

Many participants in this study were not sure that they had encountered a ghost and remained uncertain that such phenomena were even possible, simply because they did not see something that approximated the conventional image of a “ghost.” Instead, many of our respondents were simply convinced that they had experienced something uncanny—something inexplicable, extraordinary, mysterious, or eerie. (Waskul and Waskul 2016, 20)

Thus, we see why defining and explaining ghostly phenomena is slippery and problematic. Many people who will go on record as having a ghostly experience didn’t necessarily see anything that most people would recognize as a classic “ghost,” and in fact may have had completely different experiences whose only common factor is that they could not be readily explained.

Disorder in the House

It’s difficult to overstate the lack of coherent research methods and assumptions about ghosts within the ghost-hunting communities. A chapter in the book Ghosts, Spirits & Hauntings by ghost hunters Larry Flaxman and Marie D. Jones (2011) shows just how disorganized the ghost hunting field is.

Though both authors are clearly believers in the existence of ghosts and the paranormal (Flaxman is senior researcher with fifteen years of experience at the Arkansas Paranormal and Anomalous Studies Team, a member of the T.A.P.S. group and “one of the nation’s largest and most active paranormal research organizations”), they acknowledge that ghost hunters still don’t know what ghosts are. Flaxman and Jones briefly describe about a half dozen theories about what ghosts might be. The most popular idea is that ghosts are the earthbound spirits of the deceased. They admit that “this theory creates more questions than it answers” but nonetheless note that it is “the gold standard that guides most ghost hunters and paranormal researchers.” But there are of course other theories, including:

  1. Ghosts are “created by naturally occurring environmental conditions such as electricity and electromagnetic radiation”; evidence for this often comes in the form of EMF readings.
  2. Ghosts are the “‘playback’ of energy or stored human emotion that was once present in the location and then somehow captured or ‘recorded’ into the environment”; evidence of this theory is often discussed in terms of “residual hauntings,” for example. Flaxman and Jones noted that if this theory is correct, it raises questions about the legitimacy of EVPs (ghost voices), which may in fact be “merely the thoughts and feelings of the investigators.”
  3. 3) Ghosts “are very much alive and active, but present in alternate dimensions or realities.” Flaxman and Jones speculate that “if a ghostly apparition is indeed coming to us from another dimension or parallel universe, it might not be a dead person at all but a real, live person whom we are merely glimpsing across the great divide of reality.”
  4. Ghosts may be either figments of our imaginations or products of temporary hallucinations (created, for example, by brain chemicals or low-level electromagnetic fields).
  5. Ghosts “are sentient entities that enjoy vexing and even harming humans.” This theory suggests that ghosts are similar to supposed demonic entities or fairies.

In the end, Flaxman and Jones acknowledge that “the bottom line is … even when we appear to have some kind of direct communication from a ghost, we cannot know for sure that we are dealing with a spirit of the dead” (p. 41). This refreshingly candid admission is exactly correct, and it fatally undermines virtually all of the other ghost hunters and paranormal researchers in the book and around the world. The fact that neither Flaxman and Jones—nor anyone else, for that matter—can conclusively rule out any of these competing explanations for ghosts demonstrates clearly that there are no proven facts about ghosts, no certain knowledge; it’s all guesswork, speculation, and opinion often presented as self-evident truth (“our team helped the ghost to move on”) or established fact (“through EVPs the spirit told us he was angry”).

Those who might suggest that each of the different theories Flaxman and Jones present as plausible candidates for ghosts may simply be different aspects of the same phenomenon should be aware that many of the explanations are in fact mutually exclusive. For example, a ghost cannot be both a sentient earthbound spirit and a hallucination; nor can a ghost be some sort of “stored environmental emotion” unknown to science and a malevolent, mischievous spirit or live human from another dimension. These theories must be entirely different phenomena with different mechanisms. An apt analogy might be a sommelier speculating about what ingredients may have been used to create a specific table wine, but the candidates are not different varieties of grapes but instead a tree, an airplane, a football, and a dolphin. If ghost experts don’t have enough known, independently verifiable information about what they’re studying to distinguish between a hallucination, a “time slip” from another reality, or a sentient spirit of the dead with verifiable knowledge of the past, the field is in far worse shape than anyone dared imagine.

Descriptive Ghost Categories

Instead of (or in addition to) offering discrete categories of ghost epistemology, many writers categorize ghosts by their apparent intent or purpose; through this prism the ghost’s behavior determines what “type” it is.

Any speculation about a potential ghost’s motivations, however, is a frivolous and pointless task because there’s no way to independently confirm it. No matter what “answer” a ghost hunter comes up with as to why whatever phenomenon he or she perceives as something a ghost “does” (appears at a certain location, makes a specific sound, etc.), another ghost hunter might come to a completely different—yet equally valid—conclusion based on the same logic and “evidence.” Does a ghost haunt a room because she died there in 1830 or because she saw her child die from a specific window in that room or just because she likes the wallpaper? Who knows? There’s no verifiable, provable right or wrong answer as to why a ghost does anything, and therefore as an investigative technique it’s a dead end.

Even if a ghost exists, and even if it can (and chooses to) communicate its motivations to a ghost hunter, and even if the ghost hunter correctly guesses the ghost’s intent based upon taps or knocks or some other inherently ambiguous method, that doesn’t solve any mystery; a ghost hunter concluding, “I believe this ghost wanders the hallway mourning his dead wife,” even if completely true, doesn’t explain anything or give any information upon which to further our knowledge of ghosts. It’s a waste of time and effort. Determining why a ghost seems to do something is no more useful than asking it what its favorite color is; there is no independently verifiable right or wrong answer.

Another way to examine these various efforts at ghost categorization—however well intentioned—is its fruitfulness: Has it helped us understand ghosts or apparitions? So far the answer seems to be a clear no. Just as spending time deciding why an apparition has chosen to manifest itself is pointless, there’s no point in spending time trying to figure out what type of spirit is in a place. Is it Type A, B, C, or D? The answer, of course, is that it doesn’t matter; it’s not like a mechanical problem in which a person must first assess the situation to determine what tool to use for the specific job (wrench, screwdriver, pliers, hammer, etc.). No credible ghost investigator ever said, “Well, I was baffled by this paranormal haunting for weeks until I realized I’d made a silly mistake: I re-read a ghost hunting book and found out I wasn’t dealing with a residual haunting entity; it was really a poltergeist! I felt pretty silly, but once I figured that out I solved the mystery and proved the ghost existed.”

The important thing is determining whether a given apparently mysterious phenomenon (of whatever sort or category) has a mundane explanation. Guessing at—or claiming to know—why a ghost did something or what kind of spirit it might be is like trying to determine what musical note a sound is before proving or verifying that any sound exists or trying to figure out what color a light is when it’s not clear a light is even present.

This fundamental inability to decide anything about even the basic nature of ghosts is especially surprising given the fact that ghost hunting is the world’s most popular paranormal pursuit. Inspired by reality television shows such as Ghost Hunters and its ilk, tens of thousands of people around the world have taken up ghost hunting. Never before in human history has so much time, money, technology, and effort been devoted to the ostensible goal of understanding the spirit world—resulting in not a single verifiable conclusion.

If ghosts do exist and could be any or all of these different entities and therefore anything goes, then why bother to have the categories at all? If a ghost can truly be anything you imagine it to be, and have any characteristics you can imagine it to have, how is that different from an imagined ghost? Unless the definitions and explanations for ghosts are anchored in verifiable reality and empirical evidence, it’s all speculation and guesswork. When and if ghosts are proven to exist—and their differing properties can be scientifically quantified and categorized—it will be useful and important to distinguish between types of spirits and apparitions. Until then it’s merely a parlor game distracting amateur ghost hunters from the task at hand.



  • Davies, Owen. 2007. The Haunted: A Social History of Ghosts. New York: Palgrave.
  • Flaxman, Larry, and Marie D. Jones. 2011. Not quite dead: When a ghost is not really a ghost. In Ghosts, Spirits, & Hauntings: Am I Being Haunted? Ed. by Michael Pye and Kirsten Dalley. Pompton Plains, New Jersey: Red Wheel Press.
  • Newman, Rich. 2011. Ghost Hunting for Beginners: Everything You Need to Know to Get Started. Woodbury, Minnesota: Llewellyn Publications.
  • Waskul, Dennis, and Michele Waskul. 2016. Ghostly Encounters: The Hauntings of Everyday Life. Philadelphia, Pennsylvania: Temple University Press.

Benjamin Radford

Benjamin Radford, M.Ed., is a scientific paranormal investigator, a research fellow at the Committee for Skeptical Inquiry, deputy editor of the Skeptical Inquirer, and author, co-author, contributor, or editor of twenty books and over a thousand articles on skepticism, critical thinking, and science literacy. His newest book is Investigating Ghosts: The Scientific Search for Spirits (2018).