Ive seen several articles recently discussing a new book out this month: Nassim Nicholas Taleb, The Black Swan: the Impact of the Highly Improbable (http://www.amazon.co.uk/Black-Swan-Impact-Highly-Improbable/dp/0713999950/ref=pd_bbs_sr_1/203-5091590-1107162?ie=UTF8&s=books&qid=1178519926&sr=8-1). (Ill say at once I havent yet read the book itself). There was quite a good article on it in the Guardian business section (http://business.guardian.co.uk/economicdispatch/story/0,,2068696,00.html), which gives a summary of the theory:
Taleb argues that there are three attributes of a Black Swan. The first is that they lie outside the realm of regular expectations, with nothing that has happened in the past able to point to its possibility. The second is that they have a huge impact. The third is that despite being unforeseeable, human nature means we construct convincing explanations for the appearance of a Black Swan once it has happened.
However, the Guardian has also done another longer and noticeably less good article on the book (http://books.guardian.co.uk/departments/politicsphilosophyandsociety/story/0,,2067489,00.html) which discusses current events and history and shows how some people can completely miss Talebs point. This starts off by referring to events such as Cho Seung-Huis killing spree at Virginia Tech and the September 11th attacks as black swans, which needs a whole lot of more careful thought. Firstly, what counts as a black swan event depends at whether youre looking at a micro or macro level. Me inheriting a million pounds this year from a previous unknown relative is a black swan event. Somebody in Britain inheriting a million pounds this year from a previously unknown relative is statistically likely to happen. Cho being the attacker was difficult to predict (although some people had apparently warned about him). But when I heard the news on the radio, at one level my reaction was of weary predictability. Such crimes occur fairly frequently in the US and they will continue to occur fairly frequently in the US as long as gun control is so lax. If the massacre had been in Japan (or somewhere else with very tight gun laws) or in the US senate, it would have been improbable.
With the September 11th attacks you again have the question of what the impossible to predict event was. An attempt by Islamist terrorists at a huge attack within the US was not unpredictable: there had already been the World Trade Center bombing, as well as attacks outside the US. The use of planes in this way was unprecedented (as far as I know), but there had been intelligence specialists warning beforehand this was possible. The successful co-ordination of so many hijacks I dont think could have been anticipated or how many people were killed. So at one level September 11th was a black swan, but not at all of them. It was noticeable that the sense of shock at the attacks (though widespread) was less intense among Americans (and non-Americans) who had experience of cultures where terrorism is not a rare occurrence.
As this suggests, outside the realm of regular expectations depends crucially on the point of view of the observer. I can remember being shocked by Princess Diana dying in a car crash: if Id known beforehand (as some of her security men did) that she often did not wear a seat-belt, Id have been much less surprised. Maybe George W Bush couldnt anticipate the effects of Hurricane Katrina; a lot of experts had been able to. (See Barbara Tuchmans book, The March of Folly (http://www.amazon.co.uk/March-Folly-Barbara-W-Tuchman/dp/0349106746/ref=sr_1_1/203-5091590-1107162?ie=UTF8&s=books&qid=1178522534&sr=8-1, which now needs an Iraq update, for classic examples of how leaders can get into predictable disasters).
Where the Guardian article really goes off the rails, however, is when it starts talking about history and particularly counterfactual history. Some use of counterfactuals is a valuable tool in history. The article quotes from Ian Kershaw:
“If you look at major historical events, the outcome is not random or simply contingent,” says the (non-Marxist) historian Ian Kershaw, whose latest work on the second world war, Fateful Choices, has a counterfactual flavour, though he rejects the label. “There are developments which predispose the outcome, and the job of the historian is to work out what are the predisposing elements, and what is truly contingent.”
(For more on the use of counterfactuals in history, see http://www.historycooperative.org/journals/ahr/109.3/bunzl.html)
What is more dubious is that the article starts talking about the theories of Niall Ferguson and other (largely right-wing historians), arguing that the First World War etc happened only as a result of chance and had no great causes. But what the black swan theory suggests is in fact that the entire conservative idea that some big events neednt have happened is even more flawed. Such views normally rest essentially on the presumption that things could just have carried on as usual: the British could have hung onto North America, the king might have won the English Civil War, the Russian revolution might not have happened. But in fact the black swan theory suggests that shocks to the system happen more frequently than one would expect and that more of the same is less likely than you would think. If it had not been Sarajevo, some other unforeseeable event would probably have precipitated the First World War. After all, a war between the Great Powers was not an unimaginable event in the 1910s: there were even people enthusiastic about the possibility. Similarly, if George Washington had lost, would the United States really now be the southern equivalent of Canada? Or would the essential problems of taxation without representation still have festered and led to another attempt at independence? When history suggests rulers and politicians learn very little about changing the system from near misses, its difficult to avoid such unpredictable events.