In this hilarious extract from his bestselling "The Stuff of Thought" Steven Pinker takes us on a fascinating journey through the world of profanities, to show us why we swear, how taboos change and how we use obscenities in different ways. Why do so many swear words involve sex, bodily functions and religion? What are the biological roots of swearing? Why would a democracy deter the use of words for two activities - sex and excretion - that harm no one and are inescapable parts of the human condition?Taboo language enters into a startling array of human concerns from capital crimes in the Bible to the future of electronic media. You'll discover that in Quebecois French the expression 'Tabernacle' is outrageous, that 'scumbag' has a very unsavoury origin and that in a certain Aboriginal language every word is filthy when spoken in front of your mother-in-law.