Hearing and reading many legal arguments has reinforced my belief that, as great as rational argument and readily observable phenomena are, we moderns have a superstition that they can solve every kind of problem. They can't. Rationality, absent the right kinds of express knowledge, may for some applications be very inferior to intuition based on tacit knowledge or rationality based on ancient wisdom rather than readily observed phenomena as its axioms. Too often "rational argument" is just shallow and foolish rationalization and carries false authority because it seems rational.
Furthermore, our ancestors' brains as far back some hundred thousand years were just as large as ours. Why then are we so quick to believe that the thoughts in those brains were far more foolish than ours?
Thus, I've long believed that there is hidden wisdom in ancient traditions that were long followed and that evolved through little more than trial and error rather than being purposefully designed and rationally explained. On the surface to our minds these traditions may seem foolish, pointless, or superstitious, but there is often hidden wisdom to be found. If found and expressed in modern rational terms, we may find something like that wisdom applies again, rather than our current beliefs, in future changed circumstances.
Here's a possible extreme example of some hidden wisdom in ancient tradition where we moderns see only rank superstition (although it may be a silly example, too -- the jury is still out).
We now consider the ancient trial by ordeal to be a barbaric relic, and rightly so, but below I give some reasons to believe that ordeals worked to some extent, and that they were among the best methods that legal systems could have used in Europe before around the 16th century when investigators started gaining substantial ability to gather and piece together circumstantial evidence. The other widely used methods of fact finding before this period were direct eyewitnesses to the actual crime(rare), witnesses as to reputation, confession (often obtained by torture), and grand juries of close neighbors. Usually two or more of these methods were combined. In England, it was common before the 13th century to combine a grand jury of neighbors (who usually had strong local knowledge of criminal and victim as well as often being witnesses to circumstantial evidence) with an ordeal. Grand jurors had such profound personal knowledge of the defendant, a fellow villager, that they would not, as they are said to do today, indict the proverbial ham sandwich. Rather, grand juries had usually lived with the defendant and victim for their entire lives, and thus had profound knowledge of the characters and circumstances that modern juries lack. They might, however, be susceptible to bias against the defendant. The ordeal was added as an extra required step to let God, as they saw it, reverse the grand jury if the grand jury made an error or swore falsely.
Some of the most common ordeals were those where the defendant was wounded in some way. If the wound was healing well, the defendant was pardoned, and if healing poorly, guilt was confirmed. For example, a hot iron would be used to burn the hand. The hand would be bandaged up and then examined in three days.
Two theories for how the ordeal could have been effective came across my mind earlier today (in a legal history class discussing ordeals). I just searched to learn that these were previously and independently thought of by somebody posting under the nym "WolfKeeper".
The first theory is that it was an instance of the placebo effect. With the placebo effect, often people will feel less pain, be more active (e.g. walk longer on a treadmill), be less depressed, etc. on treatment they think is real, but is not (e.g. a sugar pill) than with no treatment. Whether wounds will physiologically heal faster is more controversial. However, it does seem to be thte case that more extreme treatments, such as surgery, have a greater placebo effect than convenient treatments, such as taking a small, easy to swallow pill.
Defendants probably almost always believed the religious claims about ordeals that they were truthful messages from God. Under the placebo theory, if they so believed and were innocent, their wounds would heal faster; if they so believed and were guilty, they would heal slower. The placebo effect would have been strong both because of the extremity of the ordeal and the strength of the religious belief.
The second theory may be a physiological cause of a strong placebo effect on healing, or may be independently effective, or both. This theory is that cortisol levels would have been (and may still be) elevated higher and for longer periods for guilty defendants than for innocent defendants. The most extreme effect of extended periods of high cortisol is Cushing's Syndrome which can cause rapid weight gain, easy bruising, and slow healing of wounds. Weight gain and slow healing probably often occur to a lesser extent for less extreme elevations of cortisol. Perhaps ordeal by water and ordeals by wounds, respectively, could distinguish higher levels of cortisol typical in the guilty from lower levels of cortisol typical of the innocent. (I say "could" because much of the difference in stress, and thus levels of cortisol, could have been caused by the belief by both the guilty and the innocent that God would send a truthful signal via the ordeal. Thus the effect might not be readily replicable with typical modern defendants). The counter-argument is that an innocent person on trial might by as subject to long-term stress as a guilty person. This argument will have to be resolved by experimentation, if such a study is possible with modern defendants.
A third theory, which I at first dismissed in an instant and almost subconsciously as trivial, but which might in fact be very important, is that religious belief in the efficacy of ordeals might have convinced many guilty defendants to confess, whether or not the ordeal was otherwise effective. This theory might be tested if we can estimate the frequency of confessions from the historical record.
We might not be able to ethically test the placebo theory of ordeals. But the cortisol theory probably can be tested, for example by testing, at the same early phase of prosecution (before trial is held or charges are dropped) the cortisol levels of people and seeing whether they are later convicted by juries or whether their charges are dropped early by the prosecution (assuming we believe today's prosecutors and juries are reasonably accurate!)
The Catholic Church proscribed ordeals at the Fourth Lateran Council in 1215 and they soon fell out of favor in Europe. This proscription is probably due to the effect of recovering the ancient rational thinking of Roman law and Aristotle in Italy over the course of the 12th century. If the placebo effect theory is correct, the ordeal didn't merely become unpopular with the authorities -- it actually stopped working when people stopped believing that it worked.
On the European continent, the trial by ordeal was replaced with, in many cases, confession obtained by torture. It's not clear to me that a confession extracted by torture is any less barbaric or more effective than an ordeal. Torture and confession did, however, comport more closely to the reborn Roman law. In England, which lacked the strong hierarchical control by officialdom assumed by Roman procedural law, ordeals were replaced with trial by jury. Grand juries became pro forma and the main action moved to the "petite jury" or trial jury.
Not until around the 16th to 18th centuries did Europeans learn to use circumstantial evidence effectively. The methods the Continent developed for judges to formally weigh circumstantial evidence had quite a bit to do with the scientific revolution and the development of probability theory, but that is another story. Circumstantial evidence and science are two areas where it did pay off handsomely to express knowledge and apply rational thinking to it.
My thanks to Professor Renee Lerner and her wonderful legal history class for helping to inspire these thoughts.