No system is perfect. Our criminal justice apparatus is a system. Therefore, our criminal justice system is imperfect.

A small syllogism--but it has big consequences: The murder, caging, and shaming of untold innocents.

How can we reduce our rate of wrongful convictions without making convictions impossible? The question's tough because we will never have a flawless conviction-to-guilt ratio; changes that help defendants risk helping guilty suspects as much as innocent ones.

Still: Wrongful convictions are unacceptable. Tragic. And so--in a democracy championing due process--we must act.

The first step in solving a problem is identifying its cause. Luckily, one cause is simple--so simple another syllogism can describe it: Prosecutors are human. Humans suffer cognitive biases and draw imperfect conclusions from even perfect information. Therefore, prosecutors suffer cognitive biases.

Speaking at Harvard Law in April, Making a Murderer attorney Dean Strang took this further: Since errors on guilt can be so tragic, he argued, prosecutors and police should exercise humility. Not humility concerning one's ego (though that helps), but humility concerning the evidence--and one's ability to draw correct conclusions from even complete information.

Now, it's no secret that we humans grant far too much confidence to our opinions. But when powerful people do this, the dangers compound. Zealotry replaces fair-mindedness. The worst excesses happen when prosecutors forget they're flawed humans, like anyone else, and that as a result they're subject to cognitive flaws like tunnel vision, racial bias, and the desire to reduce cognitive dissonance through "cognitive consistency" even at the expense of complicated, nuanced, self-contradictory, paradoxical truth.

Indeed, since prosecutors, police, and judges are repeat players--people who've "seen it all"--they are sometimes less well-positioned to view a case objectively than a third party. Principles like "beyond a reasonable doubt" and "innocent until proven guilty" gradually lose force, especially because our justice system today resembles less one of trials than one of pleas. This is partly why the late Justice Scalia called juries the "circuit breaker" in our machinery of justice. Citizens might take standards like probable cause and beyond a reasonable doubt more seriously than habituated legal elites.

Nothing is ever certain. Our system recognizes that by leaving room for uncertainty, making the standard for guilt "beyond a reasonable doubt" rather than "absolute" or "definite."

Crucially, Strang argued that our inability to remove uncertainty from criminal justice provides reason to do away with capital punishment. There have been innocent people on death row before, and there might be innocent people on death row right now. Is the maintenance of capital punishment worth even one innocent life?

The vast majority of prosecutors are true professionals, keenly aware of their immense power and its consequent responsibility. They form accurate conclusions on guilt far more often than the converse. Still, cognitive bias and overconfidence touch us all. Only a conscious awareness that we might be wrong can counter unthinking heuristics, biases, and schemas that lead to imperfect conclusions. For when applied to criminal adjudication, humility--as with other life questions--leads us to fuller conclusions.

Wisdom counsels not the confident use of power, but the wise use of power. The first step of wisdom is recognizing how little we know.