Totally the wrong question

This NYT op-ed on the insanity defense is infuriating precisely because it so completely misses the issue. The point of a criminal justice system explicitly should not be to determine who does and does not deserve punishment.

Let me say that again because it's important: The point of a criminal justice system explicitly should not be to determine who does and does not deserve punishment.

...and, in fact, attempts to the contrary are exactly what results in such a screwed up system of justice.

What the criminal justice system should be concerned with is creating a system of deterrents to behaviors that are deemed socially undesirable. Note how different that is from trying to tease apart the motivations of defendents: in the former case, it's vitally important to understand whether someone is acting as a rational agent when committing a crime, for we deem it "immoral" to punish someone who isn't acting rationally. But in the latter case, that distinction is secondary. More immediately important is whether the prospect of being captured and punished would dissuade someone from committing the act. Whether or not they are acting rationally is utterly irrelevent. It's a judgment on the effects rather than the causes, which means a) it's ultimately much more effective in achieving concrete ends like reducing crime, and b) it's far less subjective, both of which we can all hopefully agree are desirable.

Think about it: in the latter case, you could have someone who thought that angry pink unicorns were terrorizing a victims head and decided to rid that person of said malicious unicorns by bashing them over the head. If the prospect of being thrown in jail for actually going through with the bashing is compelling, you don't care how fucked up the logic the attacker is using is. You just care that the victim lives. At trial, you don't spend weeks upon weeks trying to tease apart whether the attacker really thought there were unicorns, whether it was reasonable to think there were unicorns, etc. You just care about the effects. If it's the case that someone can be prevented from trying to bash unicorns by threat of jail time, then bashing someone over the head, regardless of unicorns, is a crime. All you have to determine is whether the crime was committed or not by the defendant.

You might be inclined to object, "But it seems so unfair to throw someone who was just trying to help in jail!" You're missing the point. What I'm proposing is a framework of law that cares only about pragmatic implications instead of arbitrary moral judgments. Define your goals. If you care a lot about not sending unicorn bashers to jail who were, in their own minds, just trying to help, fine. Legislate to that effect. Bear in mind that you may have to balance that desire against the desire not to have random bystanders beaten senseless by unicorn hunters. But once you determine the balance between those, and no doubt a variety of other factors, you encode that balance into law, and at that point, law becomes largely deterministic rather than subjective. Granted, you no doubt still have the ambiguities in verbiage and other such imperfections in the process of encoding the law, but you no longer are teasing apart intent because it's totally irrelevent.

In a world where it's increasingly clear that nobody acts entirely rationally...ever...laws based on the faulty assumption of the Rational Man seem utterly outdated and, more than simply useless, actively detrimental. There is a line between regarding people as agents of their own rational and free will and as agents of environmental forces beyond their control that we will likely never fully nail down, so it seems stupid to try to legislate based on those fatally obscure motivations. Legislate instead on the things that are readily visible and trivially agreed upon: objective, tangible outcomes.