“Philosophers and many proponents of cognitive psychology hold that moral judgments are within our control, and thus people who choose to commit crimes, barring delusions, know what they are doing and that it is wrong. The legal system depends on this notion. However, recent research suggests that damage to an area of the brain just behind the eyes can transform the way people make moral decisions. The results indicate that the ventromedial prefrontal cortex, implicated in the feeling of compassion, may be the foundation for moral regulations, assisting us in inhibiting (or not) harmful treatment of others. Failure in its development, or damage to it, might alter the way a person perceives the moral landscape, which will thus affect his or her actions. If juries include information of this kind in their deliberations, it could mitigate the harshness of the sentences they impose on convicted criminals. While more research must be done, other types of brain scans are being entered as evidence in the trials of some heinous crimes to show that the perpetrator could not help what he did.”

“Nature consists of facts and of regularities, and is in itself neither moral nor immoral. It is we who impose our standards upon nature, and who in this way introduce morals into the natural world, in spite the fact that we are part of this world. We are products of nature, but nature has made us together with our power of altering the world, of foreseeing and of planning for the future, and of making far-reaching decisions for which we are morally responsible. Yet, responsibility, decisions, enter the world of nature only with us”

“How does something immoral, when done privately, become moral when it is done collectively? Furthermore, does legality establish morality? Slavery was legal; apartheid is legal; Stalinist, Nazi, and Maoist purges were legal. Clearly, the fact of legality does not justify these crimes. Legality, alone, cannot be the talisman of moral people.”

“Our moral decisions about ourselves can be spiritual. Our moral decisions about other people can only be practical.”

“How do we regulate our emotions? The answer is surprisingly simple: by thinking about them. The prefrontal cortex allows each of us to contemplate his or her own mind, a talent psychologists call metacognition. We know when we are angry; every emotional state comes with self-awareness attached, so that an individual can try to figure out why he's feeling what he's feeling. If the particular feeling makes no sense—if the amygdala is simply responding to a loss frame, for example—then it can be discounted. The prefrontal cortex can deliberately choose to ignore the emotional brain.”

“What, then, can we conclude about the moral value of Metallica's music? In light of our discussion, it is decidedly mixed. Insofar as it has the potential to arouse negative emotions that lead to destructive behavior, it is morally damaging. Insofar as it helps purge us of destructive emotions, it is morally beneficial. And, insofar as it engages our imaginative empathy and gets us to think more clearly and deeply about controversial issues, it is morally edifying. So, while Metallica is unquestionably a monster of a rock band, it is far from obvious that they are some kind of monster.”