Open societies are always endangered. This is especially true of America and Europe today, as a result of the terrorist attacks in Paris and elsewhere, and the way that America and Europe, particularly France, have reacted to them.
Jihadi terrorist groups such as Islamic State and al-Qaida have discovered the achilles heel of our western societies: the fear of death. Through horrific attacks and macabre videos, the publicists of Isis magnify this fear, leading otherwise sensible people in hitherto open societies to abandon their reason.
Scientists have discovered that emotion is an essential component of human reasoning. That discovery explains why jihadi terrorism poses such a potent threat to our societies: the fear of death leads us and our leaders to think – and then behave – irrationally.
Science merely confirms what experience has long shown: when we are afraid for our lives, emotions take hold of our thoughts and actions, and we find it difficult to make rational judgments. Fear activates an older, more primitive part of the brain than that which formulates and sustains the abstract values and principles of open society.