If we knew exactly what others thought, felt and did (and vice versa), then we would not have to speak to each other. What for? There would be no room for interpretation, everything would be laid down and we would have to react as we react. It is only when we assume that others think, feel and act independently from that which we ourselves think, feel and act (and vice versa), that everything becomes obscured. A dependency arises, which everyone knows well from their daily life, e.g. when playing cards or buying a used car: If I do this, then the other person will probably do that. But what happens if I only pretend to do that? Will the other party then do that which I desire, or will he see through the game?
In systems theory, this game is called double contingency. It consists of all those problems which come into play through the freedom of others (other systems). We can always interpret the behaviour or messages of others differently and we have, ourselves, no control over how we will be understood. This duplication – both sides must reckon with the freedom of the other and are not, themselves, fixed about how they understand the other – allows social systems to emerge. This is also the reason why the meaning of a situation isn’t simply available and must be discerned. Other systems have to be interpreted, they must be given meaning, and it is exactly in this way that communication arises.