Sep 26 2011

Spontanous Human Stupidity

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.

16 responses so far

16 thoughts on “Spontanous Human Stupidity”

  1. daijiyobu says:

    The Irish / gaelic word for village idiot is amadan.


  2. jhs says:

    Compare (emphasis mine):

    The assistant chief fire officer, Gerry O’Malley, said fire officers were satisfied that an open fire in Mr Faherty’s fireplace had not been the cause of the blaze.

    Well that’s okay. An open fire should not be suspect. It’s not as if Mr. Faherty died with his hair near the fire.

    …found Mr Faherty lying on his back in a sitting room, with his head closest to the fireplace.


    Another interesting seeming contradiction:

    The rest of the house had sustained only smoke damage.

    Mr O’Callaghan told the coroner that the only damage was to Mr Faherty’s remains, the floor under him and the ceiling above.

    What an odd pairing of statements.

    All this reminds me of Hume’s problem of miracles.

  3. locutusbrg says:

    Brain Dunning has done a very through examination of this issue that is concise. I recommend everyone check it out.
    A good teaching moment about critical thinking anyways even without his analysis. Great job on the 24 Steve, you kept focused even at the end. Hopefully it generated a lot of revenue for the NESS.

  4. locutusbrg says:

    Here is the link
    May 17, 2011 … People can catch on fire… but can it really happen when there is no external source of ignition?

  5. SHC is really just a government cover-up: he was killed by an alien ray gun. Go ahead, prove me wrong.

  6. Calli Arcale says:

    As I see it, people can catch on fire without any *known* external source of ignition. But just because you don’t know what the ignition source was does not mean there wasn’t one. Every case I’ve read about, they seem to be peculiarly dismissive of possible ignition sources, focusing instead on weird burn patterns. And the reason the burn patterns are weird is actually somewhat reassuring — it’s because the vast majority of people will never see someone burn to death in their La-Z-Boy. This is definitely a good thing, but it means people’s prior experiences with burning things will not be very helpful. So when somebody burns to death in a situation like this, it’s weird, and the weirdness leads them to discount more prosaic explanations.

  7. elmer mccurdy says:

    This was covered by The Straight Dope in… googling… 1979. Isn’t the Straight Dope great? I need to read the Straight Dope more. Everybody should stop reading this blog and read The Straight Dope instead. Much better.

  8. HHC says:

    The conclusion of SHC by the West Galway coroner may just be a polite way of stating that the 76 year old Irishman under investigation fell asleep by the fire had a gaseous emission which
    sparked a grand tale.

  9. SARA says:

    Steve, I beg to differ with you on the Survivors of SHC issue.
    I found a “terribly reliable”article on Wikipedia that mentioned found 2 survivors.
    One who was very charged with static electricity but managed to not catch on fire by taking off her shoes and jumping in a bathtub. But was sure that if she had caught on fire, it would have been SHC. Wow. That was a close one!
    Another woman was in flame resistant pjs, and caught fire in the kitchen and so survived. I’m just guessing, but I bet she was next to a gas stove at the time.
    There is another webpage that lists a man, who had a hole burned into his chest and lived to tell about it.

    So…I think we have found…
    OK. No real evidence, but still very entertaining stories of a survivors of an almost SHC.

    What I find interesting is that none of the survivors seem interested in prosaic explanations. If I had suddenly caught fire and lived, I’d be far more comfortable in finding an external cause than in thinking my body could explode in fire at any moment.

    Isn’t it odd that people will chose to be interesting rather than feel the comfort of understanding what really happened, so they can control the environment for future safety. What does that say about humans?

  10. I was, perhaps, too quick in my review of SHC as background for this post (which is partly why I linked to a longer article I had previously written).

    My point is that there are no cases, either witnessed or survived (which is a type of witness), in which there were any experienced details that adds anything to SHC as a separate phenomenon.

    In other words – people catch fire, perhaps even without a known source, but they do not experience anything that can be considered i’s own phenomenon of SHC, whatever that would entail.

  11. rezistnzisfutl says:

    @Locutusbrg, you will be assimilated…

    Sorry, couldn’t resist seeing how our monikers correlate!

    Anyway, it’s amazing how much BS some people will defend, for whatever reason, in spite of either no evidence or evidence to the contrary to those beliefs. But it’s even more amazing how much sheer nonsense people simply accept, even if given the most minute of thought processes will call into question that nonsense. Intellectual laziness? Maybe most people just shrug it off or don’t really think about what is being read.

    It’s just hard to believe that anyone with some level of intellegence will accept certain things, but I suppose that’s where that pesky critical thinking comes in, which doesn’t seem to be a skill necessarily beholded purely to intelligence.

  12. BillyJoe7 says:

    elmer mccurdy,

    “Everybody should stop reading this blog and read The Straight Dope instead. Much better.”

    Actually, the quality of his blog’s commentary would be much better if you took your own advice. 😉

  13. hoebywan says:

    Candling innit. Clothes are the wick and body fat the fuel. Explains most “unexplained” SHC cases.

  14. SteveA says:

    There are many reports of people suddenly igniting (though not dying) in Victorian and Edwardian times, sometimes in public in full view of many witnesses.

    I’m guessing the main cause of the ‘unexplained’ conflagrations (ie those not directly attributable to brushing against a naked flame or other source of heat) was the popularity of highly flammable celluloid in the manufacture of clothing and accessories.

    We tend to forget what tinderboxes humans used to be.

  15. SteveA says:

    Sorry, in my previous post I forgot to mention that it doesn’t take much to set off celluloid, a bit of friction or static can be all it takes.

  16. Armand K says:

    It strikes me that explaining as SHC cases of combustion where no source of fire can be identified is very much similar to “explaining” unsolved missing persons cases by alien abduction or vampires…

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