Cardano’s Gambit
by ilene - October 30th, 2010 9:53 pm
Cardano’s Gambit
Courtesy of Tim at The Psy-Fi Blog
Gamblers ‘Nonymous
Investing is, up to a point, gambling. Most of us don’t think of it in that way but if we conceive of the universe of stocks as a gas of randomly moving particles buffeted this way and that by forces largely beyond their – and certainly beyond our – control then there’s no other conclusion that can be drawn.
However, we don’t really believe this. What we generally believe is that although randomness is pervasive in stocks there’s a pattern that lies beneath the surface which we, in spite all evidence to the contrary, can pick out. For the idea that there are repeatable patterns hidden within apparently random games of chance we can thank one of our more unlikely heroes. Meet Girolamo Cardano, medieval physician, professional gambler and mathematician extraordinaire.
God’s Will
For a very long time in human history there was no appreciation or investigation of probability, the mathematics that lies behind assessments of risk. For the most part people didn’t believe in chance: stuff happened and that was God’s will. The idea that there was some order in the chaos either seems not to have occurred or to have been literally unthinkable.
Gamblers, however, did have some vague understanding that there were patterns in the randomness and quite a lot of self-interest in figuring these out. It’s no surprise that gambling figures quite large in early accounts of advances in probability theory. In Cardano, who seems to have been addicted to gambling, the will to understand and the ability to do so came together.
Elementary Probability
In many ways what Cardano figured out is today regarded as almost trivial, but at the time it was revolutionary and it allowed him an insight into why and when he should take a risk and when he shouldn’t. Perhaps the simplest example is to do with dice. At the time it was regarded as a bit of a mystery why, when three dice were rolled, the sum of face-up numbers came to ten more often than nine, despite the fact that there were six ways of summing possible numbers to both.
The answer to this conundrum is almost childishly simple to our eyes. There are twenty seven ways of combining the possible sums to ten while there are only…
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Philip R. Davis is a founder Phil's Stock World, a stock and options trading site that teaches the art of options trading to newcomers and devises advanced strategies for expert traders...
Ilene is editor and affiliate program
coordinator for PSW. She manages the site