"Give up all questions except one: 'Who am I?'. After all, the only fact you are sure of is that you are. The 'I am' is certain. The 'I am this' is not. Struggle to find out what you are in reality. Discover all that you are not -- body, feelings, thoughts, time, space, this or that -- nothing, concrete or abstract, which you perceive can be you. The very act of perceiving shows that you are not what you perceive."