Common knowledge is sometimes wrong. That is one reason why empirical science is so important; it gives us a method to verify or reject any claim, including those tagged as ‘common knowledge’. The classic example is the formally common knowledge that all heavenly objects circle the earth. It was only through Galileo’s empirical observation of Jupiter’s moons and subsequent verification that this common knowledge was challenged. Repeated empirical observations later rejected the previously held common knowledge and replaced it with new knowledge, the knowledge that heavenly objects only appear to circle the earth because the earth, itself, is rotating.

One of our modern commonly-held beliefs appears to be false. Many, if not most, people believe that we have become much more violent in recent centuries or that humans are naturally peaceful that have been made violent by modern society and institutions. This belief is often based on the great wars of the last century and genocides in places like Dafur and Rowanda. But, as Dave would point out, this is only anecdotal evidence. The empirical data paints a very different picture.

In an article on Edge.org adapted from a a TED conference lecture, Steven Pinker claims that the empirical data points to the conclusion that, in general, we are less violent now than in any time in history. From the Article:

“The decline of violence is a fractal phenomenon, visible at the scale of millennia, centuries, decades, and years. It applies over several orders of magnitude of violence, from genocide to war to rioting to homicide to the treatment of children and animals. And it appears to be a worldwide trend, though not a homogeneous one.”

Furthermore, the decline of violence seems to strongly correlate with the rise of rationalism. The article continues:

“The leading edge has been in Western societies, especially England and Holland, and there seems to have been a tipping point at the onset of the Age of Reason in the early seventeenth century.”

But what of the great wars of the 20th century? Certainly the horrible efficiency of modern weaponry increased the death toll, but the main reason appears to be simply because the world had more people who could die in wars. The death rates were much different in WWI and II in comparison to ancient conflicts.

“If the wars of the twentieth century had killed the same proportion of the population that die in the wars of a typical tribal society, there would have been two billion deaths, not 100 million.”

Dr. Pinker also offers a few explanations as to why many of us hold this false belief.

“Partly, it’s because of a cognitive illusion: We estimate the probability of an event from how easy it is to recall examples… Partly, it’s an intellectual culture that is loath to admit that there could be anything good about the institutions of civilization and Western society. Partly, it’s the incentive structure of the activism and opinion markets: No one ever attracted followers and donations by announcing that things keep getting better.”

I find this last explanation important. Recently, I’ve had Saturday visits from two groups of proselytizers, Mormons and Jehovah’s Witnesses. Both groups started by trying to convince me that modern society is hopelessly corrupt and evil. Presumably, they were planning on convincing me that their respective belief systems are the only remedies but they never got to make this point. Armed with the information presented in this article, I successfully challenged their claims and stymied their attempts to motivate me to believe.

The article goes on to list hypotheses to explain the decline of violence offered by the likes of Thomas Hobbes, Robert Wright, and Peter Singer. Regardless of the explanation, I find this as reason to be optimistic.