Why is it that, time and again, intelligent, educated people end up falling for ideas that turn out on closer examination to be nonsense? We live in a supposedly rational age, yet crazy notions seem increasingly mainstream. New Age peddlers claim to cure Aids with vitamin tablets. Media gatekeepers stoke panic and regurgitate corporate press releases in the name of 'balance'. Wild-eyed men in sandwich boards blame it all on the CIA.Even the word 'sceptic'...