The following will explore a couple of areas in which I feel that the criminal justice system of many Western countries might be deficient, from the standpoint of rationality. I am very much interested to know your thoughts on these and other questions of the law, as far as they relate to rational considerations.
Moral Luck
Moral luck refers to the phenomenon in which behaviour by an agent is adjudged differently based on factors outside the agent's control.
Suppose that Alice and Yelena, on opposite ends of town, drive home drunk from the bar, and both dazedly speed through a red light, unaware of their surroundings. Yelena gets through nonetheless, but Alice hits a young pedestrian, killing him instantly. Alice is liable to be tried for manslaughter or some similar charge; Yelena, if she is caught, will only receive the drunk driving charge and lose her license.
Raymond, a day after finding out that his ex is now in a relationship with Pardip, accosts Pardip at his home and attempts to stab him in the chest; Pardip smashes a piece of crockery over Raymond's head, knocking him unconscious. Raymond is convicted of attempted murder, receiving typically 3-5 years chez nous (in Canada). If he had succeeded, he would have received a life sentence, with parole in 10-25 years.
Why should Alice be punished by the law and demonized by the public so much more than Yelena, when their actions were identical, differing only by the sheerest accident? Why should Raymond receive a lighter sentence for being an unsuccessful murderer?
Some prima facie plausible justifications:
- Identical behaviour is hard to judge - perhaps Yelena was really keeping a better eye on the road than Alice; perhaps Raymond would have performed a non-fatal stabbing.
- The law needs to crack down harder when there are actual victims, in order to provide the victims and families a sense of justice done.
- This could result in far too many serious, high-level trials.
Trial by Jury; Trial by Judge
Those of us who like classic films may remember 12 Angry Men (1957) with Henry Fonda. This was a remarkably good film about a jury deliberating on the murder trial of a poor young man from a bad neighbourhood, accused of killing his father. It portrays the indifference (one juror wants to be out in time for the baseball game), prejudice and conformity of many of the jurors, and how this is overcome by one man of integrity who decides to insist on a thorough look through the evidence and testimony.
I do not wish to generalize from fictional examples; however, such factors are manifestly at play in real trials, in which Henry Fonda cannot necessarily be relied upon to save the day.
Komponisto has written on the Knox case, in which an Italian jury came to a very questionable (to put it mildly) conclusion based on the evidence presented to them; other examples will doubtless spring to mind (a famous one in this neck of the woods is the Stephen Truscott case - the evidence against Truscott being entirely circumstantial.
More information on trial by jury and its limitations may be found here. Recently the UK has made some moves to trial by judge for certain cases, specifically fraud cases in which jury tampering is a problem.
The justifications cited for trial by jury typically include the egalitarian nature of the practice, in which it can be guaranteed that those making final legal decisions do not form a special class over and above the ordinary citizens whose lives they effect.
A heartening example of this was mentioned in Thomas Levenson's fascinating book Newton and the Counterfeiter. Being sent to Newgate gaol was, infamously in the 17th and 18th centuries, an effective death sentence in and of itself; moreover, a surprisingly large number of crimes at this time were capital crimes (the counterfeiter whom Newton eventually convicted was hanged). In this climate of harsh punishment, juries typically only returned guilty verdicts either when evidence was extremely convincing or when the crime was especially heinous. Effectively, they counteracted the harshness of the legal system by upping the burden of proof for relatively minor crimes.
So juries sometimes provide a safeguard against abuse of justice by elites. However, is this price for democratizing justice too high, given the ease with which citizens naive about the Dark Arts may be manipulated? (Of course, judges are by no means perfect Bayesians either; however, I would expect them to be significantly less gullible.)
Are there any other systems that might be tried, besides these canonical two? What about the question of representation? Does the adversarial system, in which two sides are represented by advocates charged with defending their interests, conduce well to truth and justice, or is there a better alternative? For any alternatives you might consider: are they naive or savvy about human nature? What is the normative role of punishment, exactly?
How would the justice system look if LessWrong had to rewrite it from scratch?
Looking at the comment thread here, it seems to me that many commenters are unaware, or at least fail to remember, that in the U.S. and Canada, and presumably many other Anglospheric common law jurisdictions, well over 90% of criminal cases are these days resolved by plea-bargaining and never reach trial.
This is an essential feature of how the criminal law system works today -- the whole infrastructure of criminal courts would be overwhelmed to the point of collapse if it actually had to provide jury trials for more than a tiny minority of all defendants who get convicted. In the contemporary socially atomized and thoroughly bureaucratized society, in which law has become complex, vast, and abstruse to the point where it's completely outside the intellectual grasp of the common person, trial by jury is little more than an ancient historical relic. Focusing on juries as a central issue of the modern criminal law makes little more sense than focusing on the monarchy as a central factor in the modern U.K. government and politics. Of course, jury trials provide good material for movies and TV shows, and like in many other things, folks who haven't had any personal experience with the system tend to mistake what they seen on TV for reality.
The true backbone of the contemporary American criminal law are the discretion of the police and prosecutors to investigate, arrest, and bring charges, and the subsequent plea-bargaining procedure. You can still insist on a jury trial, but the system has developed to the point where prosecutors can wield threats that will nearly always make it safer to plea-bargain. They can crank up the list of charges to the point where even with a very small probability of being found guilty, the probabilistic expected penalty is higher than what you're offered to plea-bargain for -- and even if you're innocent, it takes a good and very expensive lawyer to reduce this probability to a negligible level. Not to mention that if things reach trial, cops and prosecutors are sometimes -- and arguably quite often -- willing to use very dirty tricks, up to an including perjury and faked evidence.
All this is not necessarily bad. Honest cops and prosecutors may well be more accurate in determining guilt than typical juries -- but any realistic analysis of the system should focus on them as the central decision-making agents on whose accuracy and honesty the quality of the system hinges, not juries.
Most hands of poker are decided without showing the cards. Does that make the cards irrelevant? Of course not; everything that happens is conditioned by the probable outcome if there were a showdown, as judged by the players in the hand. Changing one player's hand could change everything, even if no one else ever sees it.
A change in the way verdicts are reached will be much more powerful, being seen by both sides. Therefore even if nothing is done about the plea bargain system (and something should be done), the key to the game is still the "showdown".