Quote from Maverick74:
It's about probabilities. I know that any one trade's outcome is uncertain, but over a large enough set of trades, if one has an edge, that edge should be realized. This is also true of black jack. In fact, Fisher uses the casino analogy to describe ACD in that you want to be the casino owner with a small edge making as many trades as you can. Any one trade is random, but over a large enough trades, the opening ranges are significant.
There have been studies done over the years that shows momentum in itself is an edge. The edge being that momentum moves are not random. Of course when to get in and when to get out makes it a skills game just like poker.
Paul Tudor Jones has some great quotes about this in which he talks about some of the most successful traders and how their performance over 30 or 40 years cannot be random.
If one truly feels that they are making random trades with uncertain outcomes, they probably shouldn't trade. Just being the Dow over the last 100 years has produced about a 7.5% a year annualized return.