A 12-year-old boy who had been the victim of continual physical and emotional abuse took his father’s gun and intentionally shot and killed a young woman because she was teasing him.

A 25-year-old man who had been raised by wonderful parents and never abused intentionally shot and killed a young woman he had never met “just for the fun of it.” 5.

A 25-year-old man who had been raised by wonderful parents and never abused intentionally shot and killed a young woman he had never met “just for the fun of it.” An MRI of the man’s brain revealed a tumor the size of a golf ball in his medial prefrontal cortex (a region responsible for the control of emotion and behavioral impulses).

The history of abuse and the precipitating circumstance in case 3 seem to mitigate the man’s guilt: This was a crime of passion committed by a person who had himself suffered at the hands of others.

Case 5 involves the same psychopathic behavior and motive, but a brain tumor somehow changes the moral calculus entirely: Given its location, it seems to divest the killer of all responsibility for his crime.

And it works this miracle even if the man’s subjective experience was identical to that of the psychopath in case 4—for the moment we understand that his feelings had a physical cause, a brain tumor, we cannot help seeing him as a victim of his own biology.

How can we make sense of these gradations of moral responsibility when brains and their background influences are in every case, and to exactly the same degree, the real cause of a woman’s death?

Degrees of guilt can still be judged by reference to the facts of a case: the personality of the accused, his prior offenses, his patterns of association with others, his use of intoxicants, his confessed motives with regard to the victim, etc.

Once we recognize that even the most terrifying predators are, in a very real sense, unlucky to be who they are, the logic of hating (as opposed to fearing) them begins to unravel.

Here is one front on which I believe our moral intuitions must change: The more we understand the human mind in causal terms, the harder it becomes to draw a distinction between cases like 4 and 5.The book has been the subject of criticism.