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Martingale
Dec. 28th, 2006 02:36 pmBack about ten years ago, when I was living in the Bay Area, I got to talking to a guy - otherwise a smart fellow, earned quite a good living programming for one of the big names in IT - who told me had a surefire strategy for winning at roulette. He explained it to me, and it turned out that like many before him he'd reinvented the old system known as the 'martingale'. For those who don't know it, it goes like this:
- Pick a game where you have a roughly 50% chance of winning and a payoff to match. Red/black bets in roulette, coin-toss, that sort of thing.
- Make a bet.
- If you win, pocket the money.
- If you lose, double up, and keep doubling until you win, at which point you pocket the money.
As he explained to me, the laws of probability say that sooner or later you have to win, and doubling every time means that when you do win you'll win more than you lost.
It's quite a convincing argument and has bankrupted many people. The catch is that there's a limit to how much you can lose before you run out of money to gamble with. If you start with $1023 in your wallet and a one-dollar bet, you have a 99.9% chance of winning a dollar... and a 0.1% chance of losing everything in your wallet. (That's for a coin-toss; in roulette, the odds are a little bit worse.)
I was reminded of it this article, found via![[livejournal.com profile]](https://www.dreamwidth.org/img/external/lj-userinfo.gif)
james_nicoll: ( Currently there are no active or reserve Army combat units outside of Iraq and Afghanistan that are rated as )
The difference between this and a martingale is that at least in a martingale you do have a decent chance of winning. At this point, Iraq is screwed; the best we can hope for in the next few years is a low-level civil war followed by another dictatorship or theocracy that will have just as much regard for human rights as its predecessors. Keeping US troops there is unlikely to make that process any cleaner, just a little more protracted.
(I'm no longer sure whether Afghanistan is still winnable, but the chances there are at least a little better than Iraq, and it would be nice to have something in reserve for contingencies, because the world is a dangerous place and there are times when it is actually useful to have a working army at one's disposal.)
- Pick a game where you have a roughly 50% chance of winning and a payoff to match. Red/black bets in roulette, coin-toss, that sort of thing.
- Make a bet.
- If you win, pocket the money.
- If you lose, double up, and keep doubling until you win, at which point you pocket the money.
As he explained to me, the laws of probability say that sooner or later you have to win, and doubling every time means that when you do win you'll win more than you lost.
It's quite a convincing argument and has bankrupted many people. The catch is that there's a limit to how much you can lose before you run out of money to gamble with. If you start with $1023 in your wallet and a one-dollar bet, you have a 99.9% chance of winning a dollar... and a 0.1% chance of losing everything in your wallet. (That's for a coin-toss; in roulette, the odds are a little bit worse.)
I was reminded of it this article, found via
james_nicoll: ( Currently there are no active or reserve Army combat units outside of Iraq and Afghanistan that are rated as )The difference between this and a martingale is that at least in a martingale you do have a decent chance of winning. At this point, Iraq is screwed; the best we can hope for in the next few years is a low-level civil war followed by another dictatorship or theocracy that will have just as much regard for human rights as its predecessors. Keeping US troops there is unlikely to make that process any cleaner, just a little more protracted.
(I'm no longer sure whether Afghanistan is still winnable, but the chances there are at least a little better than Iraq, and it would be nice to have something in reserve for contingencies, because the world is a dangerous place and there are times when it is actually useful to have a working army at one's disposal.)
