The insanity defense and free will

In the wake of the Jared Loughner murders, here’s a debate on Who Qualifies for the Insanity Defense?” (New York Times, January 20, 2011). One ofthe panellists, Dr. Beatriz Luna, who uses neuroimaging methods to understand the development of voluntary control, comments,

The emergence of neuroscience methods that have the ability to characterize brain behavior have the promise of informing the justice system in issues like the insanity plea. However, these methods have not reached the level of identifying if an individual is a criminal and may never reach that level.

Neuroimaging methods can potentially inform the law as to whether someone has the capacity to make knowing and purposeful acts.

Even if neuroscience could provide some notion of the character of a person, the free will that the law protects may not be identifiable by neurobiological markers alone. Neuroscience can only inform the law about one of the many circumstances that underlie a criminal act. It cannot determine the ultimate culpability of a crime, which is an ethical issue.

Neuroimaging methods can potentially inform the law as to whether someone has the capacity to make knowing and purposeful acts. In cases where a person with a psychiatric disorder commits a crime, it may very well be knowingly and purposeful.

Good point. Just because a machinist, for example, believes he’s the President of the United States does not mean he isn’t guilty if he bludgeons the old lady next door to death because she “spitefully”refuses to acknowledge that fact. If the President had done it, he’d be guilty too.

Hat tip: Stephanie West Allen at Brains on Purpose