That a theme for meditation should be formulated in the interrogative is at once an indication that the kind of meditation involved is intellectual. What am I? is a simple question with a complex answer.
In this exercise you will repeatedly think of what you really are as distinct from what you seem to be. You will separate yourself intellectually, emotionally, and volitionally--so far as you can--from your flesh, your desires, and your thoughts as being objects of your consciousness and not pure consciousness itself. You will begin by asking yourself "Who am I?" and, when you comprehend that the lower nature cannot be the real you, go on to asking the further question: "What am I?" By such frequent self-studies and self-discriminations, you will come closer and closer to the truth.
-- Notebooks Category 4: Elementary Meditation > Chapter 4: Meditative Thinking > # 36