There is not enough argument in British politics, although there is no shortage of dispute. Maybe the distinction is pedantic. The two words can be interchangeable. But right now, with waves of fear and fury radiating out of the Middle East, it feels important to recognise a difference between communication that increases understanding and its opposite; between words used as tools to assemble meaningful propositions and words brandished as weapons and decoys. The sheer abundance of news, the processed info-mulch that we scoop off our screens throughout the day, is such a familiar feature of our lives that it can...