The question and our efforts to answer it reveal something unsettling; that civilisation and culture provide only the most fragile layer of defence against the encroachment of terrible darkness. This thin veil of security and freedom and rights is held in place by the flimsiest of pegs — intellectual and political freedom, respect and civility, and tolerance and the rule of law. When any one or a number of these pegs are compromised, weakened, or removed the structural integrity of the whole system that guarantees our safety and security is damaged...