Fundamental Theorem of Poker

Poker is a game of incomplete information.
You rarely ever know the exact 2 cards your
opponent holds until the cards are flipped over.

This theorem from David Sklansky is one
you should keep in mind whenever you're
faced with a decision at the poker table.

It may seem overly simple, but that's the beauty of it.
Applying it on the other hand, is not always so simple.

The Fundamental Theorem of Poker
"Every time you play a hand differently from the way
you would have played it if you could see all your
opponents' cards, they gain; and every time you play
your hand the same way you would have played it if
you could see all their cards, they lose.
Conversely, every time opponents play their hands
differently from the way they would have if they could see
all your cards, you gain; and every time they play their
hands the same way they would have played if they
could see all your cards, you lose. " (1.)

As your play improves, you should be constantly trying
to make your opponents play in a way that would be wrong
if they knew what you had.

This is accomplished by reading your opponents
and their hands accurately, and by playing deceptively.

1. The Theory of Poker by David Sklansky, 1987