Mind is something within us with the help of which we know, think, recognize, analyse, determine, imagine, and desire, and so on. We make a determination and spend some energy to accomplish any work. There must be an instrument inside us, which is used for all such functions. What exactly is it? What is its material? There is no answer to these questions. Nobody knows what it is. Nobody knows what it is made of. It cannot be perceived through our senses. So we can only say that it is a set of functions of something very fine. It is not possible to know anything about the physical existence of this internal instrument. But we are sure of its existence, because there must be something where thinking, analyzing, imagining, etc. go on all the time, something which we employ for gaining knowledge and for willing. Mind is something that does all these activities.
The mind cannot be sensed or caught in the hand or with any instrument. It is something ethereal, it is not gross matter. The actual material out of which it is made is not known. It is not possible to know that. It is a fine material, we may say, very fine – beyond our ken. Even if you go to a psychologist or a psychiatrist, he cannot tell you what your mind is. But he can observe the workings of your mind through your behaviours, your movements. I had the misfortune or good fortune, I don’t know, to take a boy, a psychiatric patient, to a psychiatrist. When he started to question the young boy, the patient, the latter said to him, ‘You are asking me about my mind. But first tell me: what is mind?’ The psychiatrist kept silent. Nobody, not even a psychiatrist, can define ‘mind’.
But, in an indirect way we can understand the mind. It is known through its functions. What are the functions? To elucidate, to appreciate, to understand the nature of things, to distinguish between the good and the bad, to take resolutions, to wake up one’s urge strong enough to materialize what one thinks. This is mind.
Mind is the greatest possession of man. ‘Mana eva manushyānām kāranam bandha-mokshayoh’ – the mind is the cause of bondage for man, and it the cause of liberation also. Both bondage and freedom exist only in the mind. When one can bring it under control, one becomes free. He whose mind is under perfect control has conquered the world. Such is the importance of mind.