In a timely post Scott Alexander investigates the evidence around the US justice system to see where, if at all, it is systematically biased against African-Americans. He looks at quite a lot of empirical evidence and concludes that:
There seems to be a strong racial bias in capital punishment and a moderate racial bias in sentence length and decision to jail.
There is ambiguity over the level of racial bias, depending on whose studies you want to believe and how strictly you define “racial bias”, in police stops, police shootings in certain jurisdictions, and arrests for minor drug offenses.
There seems to be little or no racial bias in arrests for serious violent crime, police shootings in most jurisdictions, prosecutions, or convictions.
This is important given the news coverage of the killing of Michael Brown, an 18-year old African-American in Ferguson, MI, by a white police officer. Although a lengthy grand jury investigation found that the police officer did not act unlawfully, many have rejected this verdict.
They may be motivated by a belief that the justice system is predisposed to exonerate white police officers who act wrongfully to racial minorities. This is a phenomenon I have written about in the past – one has to use one's existing beliefs to assess new information to make sense of the world at all. But Alexander's investigation of the evidence suggests that things may not be as clearly biased as they believe (or, indeed, as I did before reading the post myself).
Alexander makes an important point, however. Although law enforcement may be less biased in the US than we think, the laws themselves may still be very biased (even if that bias is unintended, which perhaps it is). Drug laws, which seem extremely unjust, will cause more injustice to African-Americans if they use drugs more regularly than other racial groups. And then there is the fact that African-Americans may be poorer on average than than white Americans, so they cannot access the same quality of legal defence.
The lesson from this may be that, though we can never escape the 'webs of belief' we construct to understand the world, we can try to be aware of the fact that we use these. If instead we decide to view disagreements about politics as existing because bad guys have incentives to fight good guys, we may end up in dark places where no amount of evidence will ever convince us that we may be mistaken.