Judge Thokozile Masipa delivers her judgment in the trial of Olympic and Paralympic track star Oscar Pistorius at the North Gauteng High Court in Pretoria on Thursday.   Picture: REUTERS
Judge Thokozile Masipa delivers her judgment in the trial of Olympic and Paralympic track star Oscar Pistorius at the North Gauteng High Court in Pretoria last week. Picture: REUTERS

JUDGES, like all decision makers, live in the shadows of type 1 and type 2 errors. The state should not detain or punish the innocent (type 1 errors). It should also not let the guilty walk free (type 2 errors).

The ruling handed down in the Oscar Pistorius case by Judge Thokozile Masipa last week has put the idea of judicial error in the spotlight. Though legal experts are divided on the calls that Masipa made on the facts and on the law, the prevailing reaction on social and other media was to slam her judgment.

I have been disturbed by the ferocity with which Masipa was knocked off her pedestal. She is now on the receiving end of misogynistic and patronising vitriol. The sad irony is that this is coming from those who claim to be speaking out for justice for a woman who was killed.

If there is one Latin phrase that I hope would make its way into popular parlance in the same way that dolus eventualis has, it is argumentum ad hominem, a practice that has become too entrenched in our public debates. That principle of classic debate, to argue based on fact and reasoning and not on irrelevant characteristics of the person on the other side of the debate, is one sorely lacking in our vicious public discourse.

On the outcome of the case at hand, I am torn. As a black woman, my sense of safety and wellbeing is already undermined by daily horror stories of abuse that range from physical brutality to workplace harassment.

I expect the state to protect me from violence. I expect the criminal justice system to create the conditions that make a reasonably safe life possible. I expect that those who spill women’s blood should face punishment proportionate to their crimes.

In these uncertain and violent times, when so much needs to be done to heal and transform our society, the desire for a strong government that wields its power unabashedly is understandable.

That being said, I also need to be protected from the might of the state.

We come from a time, not so long ago, when police could show up in the middle of the night with dubious charges, emboldened by unjust courts that would uphold these.

Having confidence that the government cannot put an individual through a Kafkaesque circus is also important to my sense of wellbeing.

There are good reasons why the state has to meet fairly high standards before meting out punishment to its citizens, on our behalf.

The criminal justice system is not infallible. It is constantly called upon to minimise the incidence of type 1 and type 2 errors.

In economic literature, early works of optimal crime deterrence argued that both errors are equally detrimental to society.

My inclination is that type 1 errors are worse. Once a society can reconcile itself with the idea of punishing an insignificant number of innocent citizens, which is what obtaining convictions at all costs in a world of imperfect information implies, it opens itself to abuse of power in general. If the price of vigilance in avoiding type I errors is an increase in type 2 errors, I can live with this, within reason.

This inclination finds support in later works such as those by economists Matteo Rizzolli and Luca Stanca, who have argued that wrongful arrests are more detrimental to society than wrongful acquittals. They come to this conclusion by introducing more realistic notions of the costs of wrongful arrests, which include lost guidance and a sense of injustice that the wrongfully acquitted do not experience.

This brings economists in line with most philosophers and legal scholars, who mostly support a bias towards the accused in the process to assign guilt, even at the risk of erroneous acquittal.

Too many wrongful acquittals suggest a system in crisis. But so would too few, if the improvement is gained at the expense of due process.

In trying to deal with the immediate danger of violence, we should not flirt with the less obvious though problematic prospect of the unrestrained exercise of state power, especially when it comes to crime and punishment.

• Makhaya is an economist