Books and Arts

Nature 436, 178-179 (14 July 2005) | doi:10.1038/436178a; Published online 13 July 2005

Dissecting the right brain

Paul Bloom1

BOOK REVIEWEDThe Ethical Brain

by Michael S. Gazzaniga

Dana Press: 2005. 226 pp. £17.50, $25.00

It matters to me what Michael Gazzaniga thinks about the brain and, if you live in the United States, it should matter to you too. In 2002, Gazzaniga was appointed to the President's Council on Bioethics and so his views on cloning, euthanasia, neurological enhancement and embryonic stem cell research will help shape US law and policy. Gazzaniga is an admirably clear writer who assumes no expertise on the part of his reader. Although he says that The Ethical Brain was written to encourage fellow neuroscientists to enter the public debate on these issues, it could be read by anyone who has an interest in the controversies that lie at the intersection of science and ethics.

Gazzaniga's main point can be summarized as: Don't Panic. He is sceptical that we will ever be able to create 'designer babies' or pills that lead to effortless improvements in human performance. He argues that 'mind-reading' techniques such as functional MRI and implicit tests of racial bias are actually of limited value when it comes to determining moral or legal responsibility. And he is confident that individuals can make competent decisions about the proper use of technologies such as cloning and neurological enhancement. With just a few exceptions, he believes the government should stay out of such decisions.

He is particularly dubious about slippery-slope arguments of the type: we can't let people do X, because even though X is ok, it might lead to Y and Y is terrible. As he puts it, "It does not make moral, political, or social sense to allow the fear of the extreme to hinder the good."

He also addresses the big questions, such as how to reconcile the common-sense notion that people possess free will and are responsible for their actions with the scientific view that, as physical objects, our actions are fully determined. Gazzaniga's solution is to distinguish brains from people — "Brains are automatic, but people are free." Responsibility is "a social construct that exists in the rules of a society, [it] does not exist in the neuronal structures of the brain". For him, scientists have nothing to say about such issues: they should stay in their labs and out of the courthouse and legislature.

This may be a bit too cautious. Even if Gazzaniga is right that responsibility is a social construct and that for a neuroscientist, no person is more or less responsible than any other, there are reasonable and unreasonable ways to apply this construct. If a paranoid schizophrenic kills someone while in a delusional state, we do not (and should not) punish him or her as we would a mafia hit man, because of what we know about schizophrenia. In this regard, science does bear on questions of moral responsibility, particularly with regard to difficult issues such as how to deal with crimes committed by teenagers, or by those with learning difficulties.

Gazzaniga is a lot less cautious when it comes to the implications of neuroscience for ethics in general. As he puts it in his preface, "I would like to support the idea that there could be a universal set of biological responses to moral dilemmas, a sort of ethics, built into our brains. My hope is that we soon may be able to uncover these ethics, identify them, and begin to live more fully by them. I believe we live by them largely unconsciously now, but that a lot of suffering, war, and conflict could be eliminated if we could agree to live by them more consciously."

This conclusion would follow if our universal moral sense had been implanted by an all-knowing and all-loving God. But biological evolution is a notoriously amoral force. Innate moral universals would have been shaped by the selective advantages that arise from caring for our kin and cooperating with our neighbours, but nothing in our genes tells us that slavery is wrong, or that men and women deserve equal rights. Such insights emerge through individual and group processes that engage all of our faculties, including our innate moral sense, but also the capacity to appreciate abstract arguments, formulate analogies, learn from experience, take other's perspectives and so on. Much of moral progress consists of using reason to override our gut feelings.

An excellent illustration of why ethics does not reduce to instinct comes from Gazzaniga's own treatment of issues such as stem cell research and euthanasia. This shows ethical reasoning at its best — rooted in common sense but also informed by a sharp, inquisitive mind and a deep appreciation of the facts.

  1. Paul Bloom is in the Department of Psychology, Yale University, 2 Hillhouse Avenue, New Haven, Connecticut 06520-8205, USA.


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