In Mobs, Messiahs, and Markets: Surviving the Public Spectacle in Finance and Politics, Will Bonner writes:
…you don't win by predicting the future; you win by getting the odds right. You can be right about the future and still not make any money. At the racetrack, for example, the favorite horse may be the one most likely to win, but since everyone wants to bet on the favorite, how likely is it that betting on the favorite will make you money? The horse to bet on is the one more likely to win than most people expect. That's the one that gives you the best odds. That's the bet that pays off over time.
And here is Charlie Munger speaking about the same topic:
The model I like to sort of simplify the notion of what goes on in a market for common stocks is the pari-mutuel system at the racetrack. If you stop to think about it, a pari-mutuel system is a market. Everybody goes there and bets and the odds change based on what's bet. That's what happens in the stock market.
Any damn fool can see that a horse carrying a light weight with a wonderful win rate and a good post position etc., etc. is way more likely to win than a horse with a terrible record and extra weight and so on and so on. But if you look at the odds, the bad horse pays 100 to 1, whereas the good horse pays 3 to 2. Then it's not clear which is statistically the best bet using the mathematics of Fermat and Pascal. The prices have changed in such a way that it's very hard to beat the system.
And then the track is taking 17% off the top. So not only do you have to outwit all the other betters, but you've got to outwit them by such a big margin that on average, you can afford to take 17% of your gross bets off the top and give it to the house before the rest of your money can be put to work.