I think some of my student, she is present here. She asked me, "What is knowledge?" The knowledge is that, "I am not this body." This is knowledge. Knowledge does not mean that how you can manufacture nuclear weapon. That is not knowledge. That is illusion. Real knowledge is to know the simple fact that, "I am not this body." That's all. But that knowledge is very rare. And to acquire that knowledge, there are so many systems. That system is called self-realization.
There is yoga system, there is jñāna system, jñāna-yoga, dhyāna-yoga, karma-yoga. There are so many yoga systems simply to come to the platform of this knowledge that, "I am not this body." And as soon as one comes to this platform that, "I am not this body," then what happens to him? Brahma-bhūtaḥ, self-realization. And what is that self-realization? What is the symptom? How I can understand that one is self-realized? Prasannātmā. He's jolly. (laughter) The . . . so long we do not come to that platform of knowledge, we are full of anxieties. And as soon as we come to the platform of knowledge that, "I am not this body," the immediate symptom is joyfulness, prasannātmā.