The Better Angels of Our Nature: the Decline of Violence in History and Its Causes
Steven Pinker
Allen Lane, 832pp, £30

For once, the publisher's advertisement does not lie: this marvellous book really is riveting and myth-destroying. In it, the psychologist Steven Pinker shows, using a wealth of histo­rical, anthropological and geographical data, how violence has declined over human history. A person living today in most parts of the world is far less likely to die by homicide, or through war, than he or she would have been
at any time in the past in virtually every part of the world.

They are "far less likely" by a factor of tens or hundreds. Life was more dangerous if you were a hunter-gatherer anywhere from Australia to the Arctic, if you were a pastoralist in the ancient Middle East, if you lived in a city state in the Roman empire, or in medieval Europe, or in colonial America, China, South America, India or Timbuktu. And whether it is the Maori genocide of the Moriori people of the Chatham Islands in the 1830s, or the Enga people of New Guinea, killing each other at a rate of roughly 300 per 100,000 in continuous warfare, forget the noble savage.

Moreover, this is easily the best time ever to become a victim of the law. If you do fall foul of the state you will not be enslaved, disembowelled, broken on the wheel, crucified, or otherwise ingeniously tortured to death in front of crowds of people enjoying the spectacle of your suffering, the fate of countless people throughout history (Pinker confesses that his gorge rose as he researched this section of the book, and it does not make for easy reading). It is even a good time to be a cat, because you will not be caught and lowered slowly into a fire for the enjoyment of the party, as happened quite commonly in late-medieval Europe.

What has caused this change in our behaviour and appetites? Although I think I detect a bias towards genetic determinism in some of Pinker's earlier work, this new book is unambiguously an investigation of historical and cultural rather than biological change. There are many factors involved, but the groundwork is the rise of Hobbes's Leviathan - the state. Its absence is the most dangerous situation facing any population.

John Locke famously poured scorn on the parties to Hobbes's social contract who handed over the monopoly of force to a sovereign: "This is to think that men are so foolish that they take care to avoid what mischiefs may be done them by polecats, or foxes, but are content, nay think it safety, to be devoured by lions." Locke was not wholly wrong, given that tyrants can be appalling enough, but Hobbes was essentially correct. The suppression of private violence by the rule of law was the first step (one can see the faltering start of the process in the Icelandic sagas). Inside a state, fighting in the courts replaced fighting in the forest or the streets. We then needed a force to diminish interstate warfare, and the principal catalyst here is the rise of trade. Commerce, as Hume and Adam Smith so clearly saw, puts us in a win-win situation; it is not difficult to find it preferable to the lose-lose situation of war.

The process of humanisation, if that is the right word, took off during the Enlightenment and it is a tonic to read Pinker's bracing defence of this against its modern detractors. In the 18th century, across Europe and America, religious wars faded, persecution declined, the notion of heresy withered, toleration advanced, law replaced the whim of the sovereign, cruelty became abhorrent, slavery became ever more problematic, and sympathy became the natural reaction to distress.

In Europe, unfortunately, the idea of the Enlightenment was quickly tarnished by the French Revolution, catalysing the Romantic backlash with its ideals of Sturm und Drang, blood and soil. It is these ideals, and not those of the Enlightenment, that festered, unhappily aided by the distorted idea that Charles Darwin had demonstrated the inevitability of conflict, until they boiled over into two world wars. But blaming the Enlightenment for Kaiser Wilhelm, let alone Adolf Hitler, is rather like blaming education for George W Bush.

As for the reason this almost miraculous transformation in people's sensitivities took place, Pinker is rightly cautious. Obviously there were agitators, such as Voltaire and the influential 18th-century Italian reformer Cesare Beccaria, but what needs to be explained is how these suddenly found an audience. One surprising factor may be the upsurge in "manners" and decency. It is much easier to treat people badly when one finds them disgusting (in his book Yuck!, published this summer, Daniel Kelly describes how parts of the brain associated with normal interactions with other people are shut down by the disgust reaction). Perhaps more importantly, increasing literacy and availability of books drove the rising ability to take other perspectives, to see things from other people's point of view (an ability attacked by the Daily Mail, for instance, or Fox News in the United States).

After the humanitarian revolution and in spite of setbacks during the 20th century, we have more recently seen something like a rights revolution. Civil rights, women's rights, gay rights, children's rights and animal rights are among the quiet revolutions of the very recent past. Advertisers in the 1950s found it quite acceptable to show husbands spanking their wives for misdemeanours and schoolmasters caning children, and to hold up minorities as the butt of humour or contempt.

Just as it would now be unthinkable to smoke in a classroom, so many of the attitudes routinely expressed just a short time ago have become impossible.

Pinker is a polymath, and his ability to recruit data from a phenomenal variety of sources is hugely impressive. He also has a startlingly lucid way of writing about his multitude of topics. He is equally at home explaining the sunk-costs fallacy, the Poisson distribution, the role of testosterone, the function of the prefrontal cerebral cortex, or the relationship between general intelligence and co-operation in the one-shot prisoners' dilemma.

Perhaps Pinker's greatest achievement is in explaining the moral philosophy of Immanuel Kant in prose that is enviably clear. Kant's insight that, in order to respect ourselves, we must respect others rightly appeals to Pinker, but he shows equal admiration for Kant's political writings, and in particular for his understanding of the conditions necessary for "perpetual peace".

Pinker is no Pollyanna. "The forces of modernity," he writes - "reason, science, humanism, individual rights - have not, of course, pushed steadily in one direction; nor will they ever bring about a utopia or end the frictions and hurts that come with being human. But on top of all the benefits that modernity has brought us in health, experience and knowledge, we can add its role in the reduction of violence." He is not complacent about the future, but grateful for the progress of the past. By savouring the accomplishment of a more peaceful world, we can become more attuned to those conditions that made it possible, and perhaps more resolute in protecting them.

Simon Blackburn is Bertrand Russell Professor of Philosophy at Cambridge. His most recent book is "Practical Tortoise Raising: and Other Philosophical Essays" (Oxford University Press, £25)