Imagine Robert is on trial for committing a series of gruesome murders. He tortured several people to death, and he shows no remorse for his actions. Neuroscientists scan his brain to determine the cause of Robert’s emotional deficits—e.g. his lack of empathy—and determine that the following regions of his brain are atypical: temporal poles, anterior cingulate cortex (ACC), posterior cingulate cortex (PCC), orbitofrontal cortex (OFC), parahippocampal regions, amygdala, and hippocampus. On the basis of their findings, Robert is diagnosed with psychopathy.
What should we make of these brain scans?
The defense may argue that they show that Robert is mad and therefore less legally responsible for his violent actions. The argument might go something like this: Robert has deficits in some of the mental capacities necessary for following the law. One is not fully culpable for what one cannot do. Robert is not fully culpable for his violent crimes.
Another interpretation is that the brain scans show that Robert is a bad person. Robert has no capacity for empathy, not because he is mad, but because he is bad. Being bad is not a legitimate excuse for committing a crime. Thus, Robert’s brain scans do not make him less culpable.
I find both of these interpretations plausible. Perhaps when Robert was younger, his brain was fully typical. However, as he continued acting violently, he gradually lost the capacity for empathy. In this case, we might think that Robert is bad. On the other hand, perhaps Robert had these abnormalities from a young age, and they help explain his long standing pattern of violent behavior. In this case, we might think that he is mad.
Pretend that the bad interpretation is correct. Robert’s capacity for empathy has gradually diminished over time because of his bad choices. If this is the case, is he fully culpable for his violent crimes?
One possibility is that Robert is not fully culpable because when he committed the crimes, he did not have the mental capacities necessary for following the law (albeit as a result of his bad choices). Another possibility is that he is fully culpable in virtue of the decisions that led to his lack of empathy and subsequent crimes. In other words, Robert may be responsible for the person he is (a bad person) even if he currently lacks the important mental capacities cited by the defense.
I don’t have a satisfying answer to the mad or bad question, nor to the culpability question. But readers who are interested may find some closure in works by Nicole Vincent, Heidi Maibom, and Marga Reimer.