A recent scientific study has shown that there is a causal link between brain damage and religious fundamentalism, as reported in this story on Salon.com.

"The findings suggest that damage to particular areas of the prefrontal cortex indirectly promotes religious fundamentalism by diminishing cognitive flexibility and openness — a psychology term that describes a personality trait which involves dimensions like curiosity, creativity, and open-mindedness."

Now it is clear why you can never successfully argue people out of fundamentalist beliefs; something that many of us have tried.

Let's be clear, the research is not saying that all religious beliefs are caused by brain damage; only fundamentalist beliefs.

Of course, this doesn't mean that we should all stop trying to persuade fundamentalists that their beliefs are wrong, but at least now, when we fail, we know that it is because they are mad.