What Do You Mean by Karma?

Karma implies, does it not, cause and effect, action based on cause, producing a certain effect; action born out of conditioning, producing further results. So karma implies cause and effect. And are cause and effect static, are cause and effect ever fixed? Does not effect become cause also? So there is no fixed cause or fixed effect.

Today is a result of yesterday, is it not? Today is the outcome of yesterday, chronologically as well as psychologically; and today is the cause of tomorrow. So cause is effect, and effect becomes cause, it is one continuous movement: there is no fixed cause or fixed effect. If there were a fixed cause and a fixed effect, there would be specialization; and is not specialization death? Any species that specializes obviously comes to an end. 

The greatness of man is that he cannot specialize. He may specialize technically, but in structure he cannot specialize. An acorn seed is specialized, it cannot be anything but what it is. But the human being does not end completely. There is the possibility of constant renewal; he is not limited by specialization. As long as we regard the cause, the background, the conditioning, as unrelated to the effect, there must be conflict between thought and the background. So the problem is much more complex than whether to believe in reincarnation or not, because the question is how to act, not whether you believe in reincarnation or in karma. That is absolutely irrelevant.  
(J. Krishnamurti, The Book of Life)