If physical action causes reaction, doesn't mental action cause reaction too? For example, Newton's third law is that if a body acts another body, so the other body reacts to the acting body.

Now consider a mental action, for example one person who loves another person: that action doesn't always cause a reaction, the other person doesn't love a person who loves.

Is not the law of action and reaction, of cause and effect, also true for mental actions as it is for physical actions?
Is Newton's action- reaction law true for only on the body? Isn't it true for our mind?


In relation to kamma the physical universe has a tendency to balance itselt out towards the zero-state. The various conservation laws can be an example of that. Take for example the law of conservation of angular momentum. If you alter one of the vectors the others vectors will "react" and change in accordance in order to maintain the zero-state. 

The most common example used is the ice skating figure doing a pirouette. Here the skater begins with arms stretched out and thereby having a large moment of inertia. Then the skater pulls the arms closer to the body and thereby decreasing the moment of inertia. In order to conserve the angular momentum something else has to change and that is the angular rotational component.

In the same way when we commit actions by body, speech or mind there will be an reaction. Like when disturbing the universe it will wobble a bit and then balance itself out again.

When that is said i do not think that your question is really about buddhism and it maybe better to ask the question on Physics SE since you will probably get a better answer there. 

When answering your question i tried to make the reaction-mechanism of our actions a bit clearer by making a comparison between the physical universe and kamma (i do not know if such a comparison is valid and this one is merely for the sake of understanding the mechanism). In buddhism we call that cause and effect as its also been mentioned previously in this thread.

Lanka