Q: Have you ever investigated a haunting you could not explain or you thought was real? Have you ever seen a ghost?

—D. Sheehan

A: As a longtime investigator into ghostly phenomena (that is, phenomena attributed to ghosts not necessarily caused by ghosts), I’ve been asked some version of this question countless times. It’s a legitimate and perfectly reasonable question with a somewhat nuanced epistemological answer. Most ghost hunters (and between two and six out of ten Americans, depending on the poll) will tell you that they have indeed seen a ghost and proceed to describe one or more vivid—though typically undocumented—experiences with what they believe to be a ghost.

I’ve investigated many dozens of ghost reports, ghost photos, and videos across the country and around the world, documented on television shows and in books, articles, and elsewhere. Many, perhaps most, can be plausibly explained, but surely—I’ve often heard—there are a few that can’t be explained, some that must be real … right?

Like UFO enthusiasts and Bigfoot hunters, ghost believers will often admit (as if demonstrating their skepticism) that many sightings are misidentifications of normal phenomena, while others are downright hoaxes. The remaining sightings, that small portion of reports that can’t be explained away, intrigue researchers. The issue is then essentially turned into the claim that “where there’s smoke, there’s fire.”

But is it true that, given the mountains of purported ghost sightings, photos, EVP recordings, and so on, there must be something there? I propose not; the evidence suggests that there are enough sources of error (bad data, flawed investigation methodology, misperceptions, misinterpretations, hoaxing, etc.) that there does not have to be—nor is there likely to be, based on the evidence so far—demonstrably genuine ghost experiences lurking amid the unsubstantiated cases.

The claim assumes that the unsolved reports and sightings are qualitatively different than the solved ones. But paranormal research is littered with cases that were once deemed irrefutable evidence only to fall apart upon further investigation or hoaxer confessions. There will always be cases in which there simply is not enough evidence to prove something one way or the other. A lack of information cannot be used as evidence for a claim, lest we fall into the argument from ignorance fallacy; “I experienced something I can’t explain” does not logically translate to “I experienced a ghost.”

In their book Ghostly Encounters: The Hauntings of Everyday Life, Dennis and Michele Waskul examine how people experience ghosts in everyday life. They found that many people

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. (20)

So, we see why verifying ghostly phenomena is problematic—even for non-skeptics. 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.

As I describe in my book Investigating Ghosts: The Scientific Search for Spirits, context is critically important to understanding such claims: Something “unknown” or “unexplained” in the context of a reputedly haunted house will be interpreted as a ghost, while something “unknown” in the context of a wilderness hike may be interpreted as Bigfoot, and so on. Because as a science-based investigator I don’t approach a given location or experience with an a priori assumption about the existence of ghosts (either generally or at the location), I am—for well-established psychological reasons—less likely to interpret what I see as a ghost.

There are two main factors involved here: the inherently ambiguous nature of ghostly phenomena and the inherently fallible nature of human perception. Ghostly phenomena are universally mundane and ambiguous. Dramatic, sensational accounts of ghostly or demonic encounters are the stuff of fiction. In other words, in the real world, verifiable “ghostly phenomena” appear at a level indistinguishable from mundane events and misperceptions or misinterpretations. Note the stark lack of good evidence, even among the glut of so-called reality ghost-hunting television shows. They’re larded with “spooky” faint lights and sounds and pareidolia-created shadowy faces and figures—all relentlessly hyped and made watchable only by Herculean efforts at video turd polishing.

Given my investigations and what I know about the fallibility of human perception—including, of course, my own—I’d be hard pressed to confidently assure anyone that I’d seen a ghost per se. To state definitively or emphatically that I had seen a ghost would be both arrogant and intellectually dishonest. We don’t know for certain what ghosts are—or, more accurately, what unique and distinctive experiences make up a ghostly encounter—so we can’t really know for sure that apparent ghostly activity is not really an invisible gremlin, telekinesis, or some other unknown, unfalsifiable force.

Skeptics are often accused of having closed minds, but in fact the opposite is true. Being open-minded means being open to the possibility that you’re wrong, that you may have made a mistake or misunderstood something that you saw, heard, or experienced. For a person to state with any certainty that what he or she saw was a ghost, he or she is in effect claiming to have carefully considered—and strongly if not definitively ruled out—all other possible explanations. The person is saying that he or she is so deeply knowledgeable about all the environmental, psychological, and other circumstances of their experience or evidence that the only possible explanation is an unseen spirit. 

This doesn’t mean I’m closed-minded. If I experienced something I genuinely cannot explain or that clearly defies the laws of physics (a chair flying across the room via some unseen force, for example, or cabinet doors opening and closing violently in my presence), I’d be both delighted and eager to investigate—and call it unexplainable if I thought it was. It would be easy (and potentially very profitable) to simply say that I had seen a ghost or at least good evidence of one. It is entirely possible that one day I will experience something I truly think is beyond any scientific explanation; if and when that happens, I will dutifully report it.

It’s often said that skeptics such as me are so personally, professionally, and epistemologically invested in skeptically examining claims that our minds are closed to real evidence that would challenge our worldviews. This is of course wrong. I would be delighted to empirically prove the existence of chupacabras, lake monsters, psychic powers, or ghosts. Nor have I staked my reputation on ghosts not existing. I have never denied the possibility of ghosts, so if I sincerely stated that I believed I had seen a ghost, I would not be contradicting myself or my previous research; I’d be updating it—as science does.

So: Have I ever seen a ghost? I don’t know—and I don’t know how I would know if I had. I’m open to the possibility but far better evidence will need to … materialize.