Moral Minds:
How Nature Designed our Universal Sense of Right and Wrong
by Marc D. Hauser, Harper Collins, New York, 489 pp, hardback £25.00, ISBNs 10: 0-06-078070-3 and 13: 978-0-06-078070-8

Reviewed for Times Higher Education Supplement, 06 April 2007

(This is the version submitted. It may have been edited before publication.)

The human moral sense is evolved and inbuilt, somewhat like our capacity for language. This is the basic argument of Moral Minds by Harvard biologist Marc Hauser, best known for his work on animal behaviour and communication. The architecture of our minds, he says, reflects our egalitarian hunter-gatherer past and reveals “leftover circuitry from the cavemen”.

Hauser begins by contrasting three approaches to moral thinking, illustrated by a series of quirky little drawings. The Kantian creature follows Kant’s categorical imperative, living by the golden rule to treat others as you would have them treat you, and never using people merely as a means to something else. The Humean creature follows Hume’s conclusion that reason is and ought to be the slave of the passions. And finally there is the Rawlsian creature, named after the political philosopher John Rawls who, with Noam Chomsky, proposed deep similarities between language and morality. Rawlsian creatures have an innate moral faculty; they can readily form moral judgements, and yet often have no idea why they hold the views they do.

This is the most obvious likeness to language explored in this book. Just as people all over the world utter grammatical sentences in their own language but have little or no insight into how the grammar works, so they construct moral codes and make judgements without insight into their reasons.

Here’s one of the many thought-provoking examples used by Hauser: the trolley problem, taken from a classic set of moral dilemmas proposed by the philosopher Phillipa Foot. Bystander Denise is a passenger on an out-of-control trolley, with an incapacitated driver, heading for five people on the track ahead. Denise can flip a switch turning the trolley onto a side track with just one person on it. Should she flip the switch? Hauser’s own intuition is that she should, and he can amass various moral arguments as to why. But now think about bystander Frank. He is on a footbridge over the same trolley with the same five endangered people. On the bridge is a large man whom Frank can push off the bridge and so stop the trolley and save the five. Should he do so?

Here Hauser’s intuition, and mine, is that he should not. But why not? Is it because of Denise and Frank’s intentions, is it because Frank would be using the man as a means, or what? In each case the result is the same, one person is killed and five are saved. But then what if a surgeon can save the lives of five dying people by taking organs from one perfectly healthy person? Almost no one says that this action is justified, but why not? By posing all sorts of weird variations on this theme Hauser reveals both how similar are the intuitions of very different people, and how difficult it is to provide logical justifications for those intuitions. Indeed he tells an amusing story of how his father, an intelligent physicist, got into a frustrated muddle when trying to find logical justifications for his immediate responses.

Hauser reviews evidence from different cultures, and from his own online Moral Sense Test, showing how judgements vary between people of different backgrounds and cultures. This builds up to another important likeness between language and morality. Languages are not free to vary without constraint; rather there are universal principles that all languages follow, as well as parameters that vary, such as the use of word order, different ways of making plurals and so on. This is the same, Hauser argues, with morality; there are universal principles and culturally configurable parameters. Also like language is that once people acquire their specific moral grammar, other grammars may seem as incomprehensible as Chinese does to an English speaker. He then goes on to discuss murder and manslaughter, the varying treatment of women, attitudes to abortion and euthanasia, paedophilia and incest, notions of fairness and punishment, and many other common moral issues.

The book is very long and very dense, so it’s not an easy read, but the wealth of detail and original arguments not only provide an excellent survey of our moral sense but provide lots of jumping off points for what I’m sure will be a productive new research paradigm.