Paul Deussen understands very well that the first teaching of Advaita Vedanta is viveka–discrimination, separation, or telling apart. What is to be told apart from what?

Deussen writes, “This aim [in essence, moksha] the Vedanta reaches by separating from the soul (the Self, atman) everything that is not soul, not Self, and is only transferred thereto falsely, thus, in a word, all Upadhi’s [sic] or individualising determinations” (The System of the Vedanta, p. 58).

You have only ever experienced yourself as the subject. Taking this cue very seriously, you can grasp that you’ve never actually been associated with, let alone mixed up with, any object. Hence, separating yourself from non-self essentially involves jettisoning all “limiting adjuncts” (upadhis): the gross body, the energy body, the mental body, the intellectual body, and the state of bliss.

Of course, the practice described in the paragraph above is not a mental exercise, for that would imply that one is taking one’s stand as the mind. But the mind is an object, and thus you must disentangle yourself from this object especially.

You are not any object, and no object is associated with you. You are nameless, formless plenum.