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Spontaneous Human Stupidity

by Steven Novella, Sep 26 2011

Spontaneous Human Combustion (SHC) is one of those classic pseudosciences that have been around for a long time – like astrology, Big foot, and the Bermuda Triangle. I put it in the same category as the myth that we only use about 10% of our brain capacity; it’s widely believed, but no one really cares that much. It’s just something people hear about and have no reason to doubt, so they lazily accept it. I did when I was younger (in my pre-skeptical days), you hear about it on TV and think, “Huh, isn’t that interesting.”

It’s therefore a good opportunity to teach critical thinking skills. People’s brains are clogged with myths and false information, spread by rumor and the media, and accepted due to a lack of having the proper critical thinking filters in place. It’s disappointing, however, when people who should know better, or whose job it is to know better, fall for such myths.

Recently an Irish coroner concluded that a man died from SHC, and it is reported:

The West Galway coroner, Ciaran McLoughlin, said there was no other adequate explanation for the death of Michael Faherty, 76, also known as Micheal O Fatharta.


The coroner said: “This fire was thoroughly investigated and I’m left with the conclusion that this fits into the category of spontaneous human combustion, for which there is no adequate explanation.”

First, let’s play a game of name-that-logical-fallacy. The core fallacy the coroner is committing is the argument from ignorance. The investigation could not find a cause for the fire, therefore here is the specific cause – SHC. The conclusion should rather be – we don’t know what caused the fire.

The coroner said the case “fits into the category” of SHC – but how? Did it have any features that are known to correlate with gold-standard cases of SHC? That is what we generally mean when we say that something fits a defined category. It seems that the coroner only means – unexplained (back to the argument from ignorance).

The case is a good example of why scientists and experts need to have critical thinking skills in addition to their area of expertise. Knowing a lot of information about a complex subject area does not necessarily also grant critical thinking skills – knowledge of logic, heuristics, and mechanisms of self-deception. This is why scientists fall prey to magicians or con-artists, and sometimes even deceive themselves and take their careers down the rabbit hole of pseudoscience.

Let’s get back to the argument from ignorance – someone might argue that it is reasonable, if no external source of fire is found, that we conclude it was therefore spontaneous. In medicine we sometimes make what is called a “diagnosis of exclusion;” once all other diagnoses have been eliminated, we are left with a diagnosis for which there is no positive evidence. But the analogy breaks down in two very important ways.

When we make a diagnosis of exclusions we are appealing to a known entity, whereas SHC is an unknown entity. For example, migraine headaches are often a diagnosis of exclusion. But migraines are a known entity, they are characterized by specific signs and symptoms, and we understand something about what causes them. We have identified specific physiological processes that are involved with migraines. We just do not have any diagnostic confirmatory tests that are sensitive and specific enough to be useful, so we rely on clinical features and ruling out anything serious that can have similar features.

SHC, on the other hand, has never been confirmed to exist – not a single case. The entire hypothesis is based upon the argument from ignorance, strange cases of immolation where the source is not discovered by investigation. I should note that many cases presented as SHC do not even fit this category as there are obvious external sources of ignition or fire, like smoking or fire places. But if we take the best cases, they are based entirely on not knowing what the source of fire was.

There are no proposed mechanisms of spontaneous ignition that even approach plausibility. There are no cases where a person spontaneously combusts while being witnessed, or cases where other animals (animals that do not routinely use fire) spontaneously combust. There are no cases of near combustion, where someone heats up for an unknown reason but does not reach the ignition point. Nor are there cases where someone combusts spontaneously but survives to tell the tale.

All we have are cases where a corpse is found burned, with fire damage to the surroundings, and no witnesses as to what happened. In many cases there are obvious fire sources. In other cases there are no obvious sources, but there are potential sources. In decades of investigating fires it makes sense that there will be the occasional case where the source of fire cannot be discovered. The alternative is to believe that fire investigators will be 100% successful in explaining every case they come upon, which is an unreasonable expectation.

This falls under, therefore, what I call the residue effect. For any frequent phenomenon there will be a certain number (a residue) of cases that defy explanation, just by chance alone, because there are quirky, unique, or highly unlikely circumstances. Very unlikely things happen all the time, given enough opportunity. It is therefore not only the argument from ignorance, but utter folly to conclude that such cases have a paranormal or fantastical explanation, rather than they are just unusual but still mundane cases.

The coroner in this case should have concluded that the cause of the fire was unknown, not that it fit into a non-existent category of SHC. But at least he provided another teaching moment for the promotion of critical thinking.

32 Responses to “Spontaneous Human Stupidity”

  1. Jarvis Puttinghet says:

    In the news article it states that the fire officers were satisfied that open fire in the fireplace hadn’t been the cause of the fire. But the fire in the fireplace was lit when he died… So I dug a bit deeper and I found that the officers only said that the fire hadn’t spread and hadn’t been the cause of death. Michael Faherty was old and in ill health and would be easy for a spark from the fireplace to jump to a dead body.

    • Jarvis Puttinghet says:

      After reading the BBC article, I have one more thing to add. Ciaran McLoughlin defends his ruling by saying that the case is similar to cases mentioned in Bernard Knight’s book.
      But if you actually go and read that book, it turns out that Bernard Knight writes ‘spontaneous combustion’ between quotes and goes on to say that they seem to always occur near fireplaces and chimneys. Someone with such a low reading comprehension as Ciaran McLoughlin should not hold a public office.
      Anyway, I think the basic point of Steve’s article still stands, you can’t say ‘we don’t know what did it, so it must be X’. But it took me only a few minutes to find these two very damning (for the coroner) tidbits and the article would have been much stronger with them. An important part of skepticism is to read more than just the press release and I’m disappointed that Steve didn’t do that.

  2. Retired Prof says:

    For those interested in details about other suspected cases of SHC, check out Joe Nickell’s article “Not-So-Spontaneous Human Combustion” in *Skeptical Inquirer* at

  3. There is also more info in the article I linked to at the beginning of this post.

    Jarvis – thanks for the extra info. In my defense, it’s Monday morning, I had to get to work, and I am still recovering from my 24 hour show over the weekend. :)

  4. tmac57 says:

    The BBC News had a more balanced view of this story:

    “Retired professor of pathology Mike Green said he had examined one suspected case in his career.

    He said he would not use the term spontaneous combustion, as there had to be some source of ignition, possibly a lit match or cigarette.

    “There is a source of ignition somewhere, but because the body is so badly destroyed the source can’t be found,” he said.

    He said the circumstances in the Galway case were very similar to other possible cases.

    “This is the picture which is described time and time again,” he said.”

  5. Max says:

    “There are no cases where a person spontaneously combusts while being witnessed”

    The Skeptoid episode on SHC cited a couple instances of “Spontaneous Human Combustion of the Second Kind is when the event is witnessed and we have accounts of what took place.”

    • My point was that there are no cases of witnessed SHC – meaning that the witnessed account contains details that would provide positive evidence for the spontaneousness of the combustion. There are certainly witnessed instances of things, people, animals catching fire – but not spontaneously combusting.

      • Max says:

        What details would provide positive evidence for the spontaneousness of the combustion?

      • Jarvis Puttinghet says:

        Personally, I wouldn’t think any eyewitness account alone positive evidence for spontaneous combustion (or anything else for that matter).
        On the other hand, if we can make pigs spontaneously burst into flame in the lab, under circumstances consistent with a domestic setting, then we’re talking.

      • Sheila says:

        I think madscientist wants to sign up to be your guinea pig.

  6. Max says:

    Does the residue effect apply to, say, the Casey Anthony case, where the evidence points to murder, but hey, it could be one of those residue cases with highly unlikely circumstances.

    • Jarvis Puttinghet says:

      The evidence didn’t point to murder. The only thing we really know is that Casey tried to hide Caylee’s body and misled the authorities.
      Some people argue that a normal person wouldn’t have done so if the death had been natural, but a) Casey wasn’t normal and b) even a normal person might hide a body if he thinks the verdict will be inconsistent with what actually happened.

  7. Max says:

    “But migraines are a known entity, they are characterized by specific signs and symptoms, and we understand something about what causes them.”

    We understand something about the cause now, but in the past we didn’t. Same as with various syndromes like IBS and AIDS, and most autoimmune disease for that matter.

    • And until we understand something about cause, it is always a question whether or not an entity is its own real disease.

      Or are we dealing with a “garbage pail diagnosis” – which is the term used, essentially, for a false diagnosis of exclusion.

      In essence, SHC is a garbage pail diagnosis for death by fire where the ignition source is unknown – an argument from ignorance.

      We take diagnoses seriously, however, when they present with a fairly specific collections of signs and symptoms that do not fit an existing entity, and at least provide compelling clues as to a plausible cause.

      What are the signs that a case of death by fire was spontaneous – other than lack of known ignition source? From the cases I have read they have little more than anomaly hunting, and the anomalies are all over the place. And they ignore signs of external ignition.

      In other words – there are no signs that SHC is it’s own real phenomenon, and alleged cases that are witnessed or survived do not add any such details – so they are really just cases of people catching on fire, not spontaneously combusting.

      If SHC were a real phenomenon, than witnessed or survived cases would probably provide some new sign that was specific to SHC and provides a clue as to cause. But we have nothing.

  8. Sheila says:

    What are the chances that madscientist will spontaneously combust?

  9. BillG says:

    Wow, I must be out of touch with today’s bunk. I thought SHC died with the Dodo bird and the Flat Earth Society – oops, aren’t they still around??

  10. I wonder what the coroner would have to say if you choked on a chicken bone.

    “This death was thoroughly investigated and I’m left with the conclusion that this fits into the category of a failed attempt at channelling a chicken, for which there is no adequate explanation.”

    I fly out to the UK to live in less than three weeks. If I should meet my doom whilst traveling remotely close to this coroner’s office, I hope the cause of death is blatantly obvious…..with detailed notes and possibly some diagrams.

  11. Jason says:

    Another one of those “you cant prove it WASNT xxxx” scenarios so many believers fall prey to as I imagine Dr. Shermer points out in his new book (havent caught up enough on other books to pull it off the shelf yet).

  12. d brown says:

    It’s been shown that pigs can burn like that. Put them in a chair and all that was needed is a small fire that burns till it gets to fat. The Nazis used that to get rid of human remains. They had it down to a science. They would dig a pit, put just enough fuel in it and stack the bodies like a wood fire. The fat did the burning once it started.

  13. d brown says:

    think of a oil candle, to stay small it needs a wick