Tuesday, June 24, 2008

Randomness and Probability

A typical English summer's day - bright start, cloudy middle, bright end.
By lunchtime the need for relaxation and conversation afflicted Nosher and me so deeply that the bottle of parsnip wine was taken from Nosher's solar-powered fridge and we sat in our deckchairs on the grass outside Nosher's old shed, a glass in our hands.
'I've been reading an interview with Nassim Nicholas Taleb that my brother sent me' I said 'I think it appeared in the Sunday Times.'
'Getting into celebrities, are we?' asked Nosher.
'Apart from liking parties, I don't think this guy is a celebrity - he's a former options trader with a PhD in mathematical probabilities, and he's made a fortune applying his methods.'
'So what's so special about him?' Nosher persisted 'is he going to save the world?'
'He bet on long-shot options that relied on market downturns to make money, and when the inevitable downturn came, he was one of the few who made a lot of profit' I explained 'and, no, he doesn't claim to be able to save the world. But what he does say is rather more interesting than that.'
'Which is?'
'That experts who claim to be able to predict the future - especially in the money markets - are kidding themselves and everyone who believes what they say. Mathematical probabilities are only a guide to how the world should work in ideal conditions. If a coin's been flipped 50 times and comes up heads each time, Taleb says that the conventional wisdom that the rules of statistics still apply is mistaken: for it's so unlikely that heads would come up 50 times that it is reasonable to believe instead that the coin has been tampered with and it will come up heads again for sure.'
Nosher took a sip of his parsnip wine and frowned.
'What's so new about that?' he said 'we all know that human beings are by nature unpredictable, and many are devious and dishonest, and will swing the odds in their favour any way they possibly can. What's Taleb saying that's new?'
'I haven't read his book yet' I confessed 'it's called the The Black Swan: The Impact of the Highly Improbable, but apparently he argues that bankers and economists are subhuman and very dangerous, because they believe the world can be controlled using mathematical models and risk-management systems, whereas history tells us that human behaviour does its best to confound even the most elaborate predictions. And the book is selling very well, so it seems.'
Nosher smiled.
'So this guy is saying that the most prevalent characteristic of human behaviour is its irrationality?'
'Possibly - I'll let you know when I've read his book. But he has only contempt for militant atheists like Richard Dawkins. Taleb says that religion isn't about belief and has more to do with aesthetics, although he acknowledges the problems of intolerance it can engender.'
'Sounds rather like your view then - not the content of belief but the manner of believing, and all that?' Nosher said.
'Yep, possibly some common ground there.'
'Well, one thing's for sure' said Nosher 'This Taleb guy is better at selling his book then you are!'
More from http://www.overthegardenfence.blogspot.com/ soon.
Find out more at http://www.paulsturdee.co.uk/
and http://www.pgsbooks.co.uk/
Paul Sturdee's book Is God a Terrorist? is available from all good booksellers; please support your local bookshop - if you don't, it may not be there next time you visit!
If you have any difficulty obtaining a copy, contact the PGS Books website.
Wishing you a nice day, take care, and be sure to enjoy your irrationalities!


No comments: