Sri Chinmoy: One of the quickest ways to silence the doubting mind is to feel that the mind itself is just a full wastepaper basket, something that you have to empty. Another way to silence the mind is to consciously say, “I have no mind, I have no mind, I have no mind. I have only the heart, I have only the heart.” That way also you can silence the mind.
But in your case, it is not the mind that is the problem. Your vital does not aspire; that is where the problem starts. Your difficulty is that your vital is tamasic, lethargic, and so your brilliant mind is very restless, doubtful and destructive. In your case, your doubt comes from the unaspiring vital. The vital means determination, or will-power, let us say. You are lacking in will-power in your dynamic vital. If you or anybody else is wanting in will-power in the vital, automatically you will suffer from the doubting mind. If the vital is strong, dynamic, then the heart is able to give peace, love, light and bliss from the soul. Then the heart and the vital can and will go together, and with the soul’s help, automatically they can silence the mind. In your case especially, make the vital very dynamic, progressive, and do not allow it to remain lethargic.