Patricia Churchland review Michael Gazzaniga's new book, The Ethical Brain, in the latest edition of American Scientist.

At a time when intellectuals may feel cowed by the heavy hand of the fervently religious, it is a relief to see that Gazzaniga neither shies away from controversial opinions nor waters them down so as to offend nobody. At the same time, he is respectful of moral convictions that do not line up with his own. His opinions are delivered not as dogma but as part of an ongoing reflection and conversation, in which seeing all sides of a moral problem is itself regarded as a moral achievement.

An overview of Gazzaniga's argument can be found in his Scientific American Mind article (with Megan Steven), "Neuroscience and the Law." Gazzaniga argues that "the brain is determined, but the person is free" and that responsibility is not a neurobiological property, but instead a "human construct" that should be considered in a social context. In the Scientific American article he writes

Neuroscience will never find the brain correlate of responsibility, because that is something we ascribe to people, not to brains. It is a moral value we demand of our fellow rule-following human beings. Brain scientists might be able to tell us what someone's mental state or brain condition is but cannot tell us when someone has too little control to be held responsible. The issue of responsibility is a social choice. According to neuroscience, no one person is more or less responsible than any other person for actions carried out. Responsibility is a social construct and exists in the rules of the society. It does not exist in the neuronal structures of the brain.

But Churchland is concerned about the "dualistic legal fiction" of the determined brain and free (responsible) person. Her objection is that neuroscience is not irrelevant to questions of guilt or innocence.

...although responsibility is assessed in a social context, the capacity to learn social norms and the capacity to act in accordance with them are matters of individual brain function. It is precisely because an important difference exists between a normal brain and the brain of someone who is seriously demented or unreachably deluded that such people are not considered responsible for crimes they might commit. Moreover, judicial institutions rely on threat of punishment to deter. The late maturation of the prefrontal cortex (with reference to neuronal density, synaptic density, dendritic length and myelination) means that the brains of mature adults are critically different from those of young children?which almost certainly accounts for the child's more modest ability to appreciate the consequences of his or her choices and to resist temptation.

I haven't finished reading the Gazzaniga book myself yet, but it looks to something I should consider for either my class next fall or for the CNS discussion group.

American Scientist Online | Brain-Based Values

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