Moral Tribes: Emotion, Reason and the Gap Between Them and Us by Joshua Greene; book review

Joshua Greene, a Harvard psychologist turned moral philosopher, gets it right about at least one thing in Moral Tribes. “This is an ambitious book,” he tells us on page five. Its goal? To find “a metamorality, a global philosophy that can adjudicate among competing tribal moralities”. So, an answer to all conflicts between the world's nations, cultures, religions and factions? As a reader, you can't help but wish him luck.

Unfortunately Greene's prose suffers from an uncanny ability to make the most profound things sound clinical – love is “a highly specialised piece of psychological machinery” - and he also appears to have a narrow understanding of politics and history beyond the shores of the United States.

The Israel-Palestine conflict is a “political dispute...bedeviled by competing claims to specific parcels of land, grounded in the authority of various proper nouns.” Already it's hard to imagine that the people who really need a book about overcoming triablism will give it the time of day.

But then, Greene can claim to have done something older moral arbiters could not. Thanks to modern brain imaging, he can see what goes on in our minds when we make moral decisions. His main assertion is that our brains, beautifully shaped by evolution to foster cooperation between individuals, have an in-built tendency to produce “automatic” moral judgements – what we know as gut feelings.

This becomes a problem, he contends, when our brain's automatic setting tells us, for instance: 'this person is not a member of my tribe and therefore I feel hostile toward them'.

The motivating idea behind Moral Tribes is to help us overcome such thoughts when they lead us astray. His solution involves dusting down the old moral code of utilitarianism: the greatest good for the greatest number – regardless of tribe.

According to Greene, utilitarianism has struggled to win supporters because the “automatic” part of our brains makes us naturally inclined to reject certain utilitarian judgements simply because they don't “feel” right. But there is another section of the brain – the dorsolateral prefrontal cortex – which is very good at working out the drawbacks and benefits of an action in a utilitarian manner. Greene's conclusion is that we should listen to this, our brain's “manual mode”, when tackling society-level problems, rather than following the gut feelings created by our brain's more automatic settings.

It all amounts to a plea to think a bit harder about what's best for everyone when tackling complex moral debates. It's a worthy message, but one suspects that the world's tribes might require something more persuasive than the academic reasoning of a Harvard psychologist before they swap their holy books and manifestos for Stuart Mill and Jeremy Bentham.