Poker players understand that a lack of knowledge of past events is exactly the same as uncertainty about future events. For example, if the first round of hol

Poker players understand that a lack of knowledge of past events is exactly the same as uncertainty about future events. For example, if the first round of hold em has dealt two cards to each of 9 players, there are 18 cards out and you only know the state of two of them. The odds that the flop will contain specific cards that help your hand are calculated against the total number of unknown cards, regardless if the unknowns are held by other players or still in the deck. For example, you get a pair of 3s. There are two more threes in the deck, and it is pretty likely that if the flop contains one of them that you will have the best hand at the table at that point. For the first card turned up at the flop, there is a 2/50 chance it will be a three, the next is 2/49, the next 2/48. It doesn't matter how many face-down cards have been dealt to your opponents. All the unknowns are still in the pool of possibilities, and it is no different when you assess the evidence you have of any other type of event that has already happen. Each bit of evidence means what means, and the unknowns contribute to the pool of uncertainty.