Harvard Professor of Psychology Steven Pinker 

Cognitive neuroscience suggests that morality is driven not just by the limbic circuits underlying emotion but also by parts of the prefrontal cortex that underlie abstract thought. And the historical record shows that many humane advances were initiated in the realm of ideas. Philosophers prepared careful briefs against slavery, despotism, torture, religious persecution, cruelty to animals, harshness to children, violence against women and frivolous wars. These arguments were disseminated in pamphlets and bestsellers and debated in salons and pubs, and then in conventions and legislatures that implemented reforms.

Advocates of reason and its gifts, such as science, technology and secular democracy, should no longer feel that they must be on the defensive. The association between the best and the worst of the twentieth century was always crude, and it is time to re-examine it in the light of statistically literate history. Almost seven decades after the horrors of the first half of the twentieth century, we now see that they were not a new normal or harbingers of worse to come, but a local high from which the world would bumpily descend. The ideologies behind them were atavisms that ended up in the dustbin of history, and the ideal of universal human rights, which would have seemed saccharine or incoherent to our ancestors, has become the moral commonplace of our age.

From: Taming the Devil Within Us, by Steven Pinker Nature October 20, 2011