Steven Pinker addressed the Institute of Art and Ideas with his thesis outlining a decline in violence over the course of recent centuries. Is this the case and, if so, why?

"Violence has been in decline for long stretches of time, and today we may be living in the most peaceful era in our species' existence. The decline of violence has not been steady, it has not brought rates of violence down to zero, and it is not guaranteed to continue, but I hope to persuade you that it's been a persistent historical development visible on scales from millenia to years, from the waging of wars to the treatment of children and animals." Steven Pinker

It's certainly a substantial claim, and one that has stimulated much debate over the past year. Some have reviewed his book, "The Better Angels of our Nature: Why Violence has Declined", as a supremely important study of human nature. However, John Gray has attacked it as displaying a misplaced faith in an enlightenment teleology.

While Gray is strong in unpicking Pinker's rationalisations about why this decline has occurred, he fails to challenge significantly the main point of the book: the decline of violence itself. Dismissing Pinker's susbtantial research as "impressive-looking graphs and statistics...[that do] not, in the end, rest on scientific investigation", Gray points to the numerous wars that have dotted the 67 years of supposed Great Power peace since the end of the Second World War as refuting Pinker's view of reduced conflict. Yet Pinker doesn't ignore these but instead has placed the admittedly still horrific violences of 20th-century conflicts in their proper historical contexts of frequency and population proportion.