More specifically, how would implementing this as a smart contract prevent bias from making its way into the algorithms or the learning datasets?
Remember that bias can be inserted accidentally, by well-meaning programmers who don't realize that the data they are using is biased or has other methodological problems.
Try reading anything at all about the jury selection process, and you'll be shocked at how abysmal our existing system is.
People tend to dismiss machines as being cold, calculated, and emotionless, but that's exactly what we WANT if we're aiming for equal, fair justice for all.
The law is a human construct, not a computer program. It is precisely because of issues of bias, fairness, methodology, etc. that the law is complicated and needs to be administered by people who can understand the complexities and use their education and initiative to ensure fair outcomes.
It's not perfect, and it never will be. But the legal system was designed with the assumption that judges and lawyers would be able to use discretion. To apply rigid computer logic on top of a system that was intentionally designed to be subject to human discretion would be a disaster.
Indeed, although unpopular, technological advances in things like data logging and DNA testing are able to establish both guilt and innocence in a much more scientific manner than a judge crippled by such things as their current mood (maybe they had an argument with their spouse before hearing the case and now they're feeling particularly vindictive) and whether they "like" the defendant as a person (maybe the defendant looks like their high school bully).
The Innocence Project has successfully exonerated many convicted "criminals" solely on the basis of DNA evidence, some of whom have been behind bars for many years. If that doesn't point to an extremely biased and flawed existing judicial system, I don't know what does.
When I think of bias in the judicial system, I don't immediately point the finger at machine learning algorithms and say "if we implemented these types of systems, then we'd be biased" -- instead, I look at peer juries and law enforcement officers as the source of bias, things like "Stop and Frisk" or "driving while black." You have very faulty systems in place like plea bargaining which effectively nullify due process and encourage false confessions in order to obtain a guaranteed lighter sentence. You have prosecutors with their own illicit motives like appearing in public to be "tough on crime" resulting in such atrocities as Aaron Swartz -- this very concept of "making an example out of somebody" is a biased one.
Someone brought up the point that "bias can be inserted accidentally, by well-meaning programmers" in an unintentional matter. On the other hand, right now, instead of employing some well-meaning programmer who is trying their very best to make sure things are fair, you have policies in place like racial profiling which are INTENTIONALLY biased. Which is worse?
In my mind, ML has the potential of creating a bias-free judicial system more than we could ever hope for by continuing to rely on fickle, highly error-prone, and even outright malicious humans. People just need to get past the fact that a "cold-hearted," emotionless computer is in the judge's chair because that's EXACTLY what we want.
That is not what I want. You should not want that either. If our current laws were implemented strictly and impartially, without reference to mitigating circumstances, the results would often be unfair, unjust, and morally wrong.
An emotionless computer would not consider any mitigating or unusual circumstances unless it was programmed to do so in advance -- but not all of the the circumstances that might come up in court are going to be obvious to the programmers.
Even foreseeable mitigating circumstances would be very difficult to program correctly, e.g. the difference between valid self-defense and manslaughter depends heavily on the state of mind of the defendant. Good luck teaching a computer how to deal with such a problem in a fair and just way, unless you can manage to develop the first artificial general intelligence.
Good luck getting a HUMAN to deal with such a problem in a fair and just way!
Even in the best legal system in the world, you'll be able to find a rapist or murderer who got away with it. That's not a valid counterargument.