Trial by Ordeal

ordealPeter Leeson of George Mason University (currently visiting the University of Chicago) offers a new take on the medieval practice of “trial by ordeal”:

“For 400 years the most sophisticated persons in Europe decided difficult criminal cases by asking the defendant to thrust his arm into a cauldron of boiling water and fish out a ring. If his arm was unharmed, he was exonerated. If not, he was convicted.”

According to Leeson, this is less crazy than it sounds: As long as defendants believe (superstitiously) that ordeals yield accurate verdicts, guilty defendants always confess to avoid the ordeal. At the same time innocent defendants always opt for the ordeal—and are always acquitted, provided the priests cheat by (for example) substituting tepid for boiling water, or “sprinkling” a few gallons of cold holy water over the cauldron, or liberally redefining what counts as “unharmed”.

Not only does the system work, but it’s continually reinforced. Even the superstitious masses are smart enough to figure out that their equally superstitious neighbors opt for ordeals only when innocent; therefore they expect all ordeals to yield acquittals, and their expectations are always confirmed.

If not everyone is perfectly superstitious then the story is a little more complicated. Still, as long as there’s a healthy amount of superstition floating around, and as long as the priests are eager to convict the guilty and acquit the innocent, you’d expect most ordeals to yield acquittals, and you’d expect non-believers to be denied the ordeal option. (After all, the system works only as long as the participants believe it’s rigged not by the priests but by God.) And indeed, there’s some historical evidence for these and other prediction of the Leeson theory. See his paper for more.

(The image at the top is by the children’s book illustrator Jeffrey Brian Fisher.)


10 Responses to “Trial by Ordeal”

  1. 1 1 Adam

    Not to get defensive, but don’t you mean “Peter Leeson of George Mason University”?

  2. 2 2 Steve Landsburg

    You’re right. I’m fixing this.

  3. 3 3 Al V.

    Isn’t that basically how a lie detector works? A person who believes that he will be caught in a lie will be nervous, and therefore the lie will be detected. A person who doesn’t believe that the lie detector works won’t be nervous, and thus won’t be detected.

  4. 4 4 Sierra Black

    What happens if the defendant weighs the same as a duck?

    More seriously, this sounds completely insane. I mean, the caveats you include where there is no corruption on the part of the priests, the jurists, the defendants or the public might make it work reasonably well in many cases…but that’s never been anyone’s reality. In reality the priests can and I’m sure did game the system to suit their ends, which don’t always line up with uncovering the truth behind a crime.

    We know in modern times that guilty defendants don’t always confess to avoid horrible punishments; many are willing to go to their deaths protesting their innocence rather than admit to a crime they committed.

    Likewise, the innocent often confess guilt when motivated by fear, mental illness or the desire to protect a loved one. There’s nothing the ‘trial by ordeal’ system to deal with these problems, even if the priests and officials running the pot of boiling water were all altruistically in on the scam to weed out the guilty by scaring them with pots of water.

  5. 5 5 Steve Landsburg


    In reality the priests can and I’m sure did game the system to suit their ends, which don’t always line up with uncovering the truth behind a crime.

    Bingo. This is exactly what bothers me about this paper, and I’ll blog more about it (and about the larger issues it raises) in the next few days.

  6. 6 6 Brad

    Can you do a blog on the economics of superstitions?

  7. 7 7 Joe Z

    Considering the accused had no civil rights, trial by ordeal was astonishingly fair. There is actually a hint of justice here. I can’t imagine what manner of trial might have preceded it.

  8. 8 8 Snorri Godhi

    The Darwinist approach to this is that, if trial by ordeal survived for so long, there must have been a good reason (though not necessarily that it statistically led to a fair outcome); and if it disappeared, then there must be a reason for that as well (though not necessarily that the new system is more fair).

    Sierra Black bringing in Monty Python gives me the chance to remark on a strange fact: trial by ordeal disappeared just when the European intelligentsia started to believe in witches. Contrary to popular belief (or at least contrary to my own belief before I read Trevor-Roper’s essay on witch hunting), during the “dark” ages it was heresy to believe in the existence of witches. Only around the time when Tommaso d’Aquino reconciled faith with reason, the European intelligentsia started to use witch hunting as a means to keep down the rednecks.

  9. 9 9 Jon

    It’s an interesting paper. I wonder how often the process broke down. With, presumably, the priests gaming the system I would expect there to be occasions where too many people lost their belief in the accuracy of the system, creating the ‘more people are found guilty-more people stop believing until all people are found guilty of the crimes they are accused of(or, more likely, until the current judicial system produced such high conviction rates that it was given up on)scenario.

    Alternatively, if this didn’t happen, what is the likelyhood that someone who is accused is, to varying degrees, aware that the priests are acting as the arbiters and deciding whether or not they are guilty? In this scenario, wouldn’t people accused of crimes base their decision on whether or not to accept the ordeal based on their estimate of the probability of the priest believing them? This would mitigate the nonbeliever/skeptic problem (unless things were radically different back then, most skeptics probably didn’t need convincing that the preists were running a crooked game) and help prevent the ‘all people must be found guilty because no one believes in the system’ scenario.

  10. 10 10 dave

    crime and punishment:

    how can deterrence work given that a criminal through the act of commiting a crime proves themselves indifferent to the consequences.

    the only penalty worth commiting crime for is the economic one. a company is forced to pay a fine for pollution for example; if the fine is lower than the cost of not polluting, they would continue to ‘rationally’ commit the crime.

    the ‘how strong is your belief in your innocence?’ test is a poor system of justice, as sierra previously pointed out.

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