I remember my participation to an "I AM" workshop in the eighties... The techniqure was to work by couples and ask the partner "Who are you?", listening to the answer, then getting again to "who are you?", etc. After a while partners were shifted and the process went again and again all day long.
Through this process the usual definitions we use to organize ourselves as "solid identities" fall away like dead leafs, they reveal themselves as immaterial beliefs creating the illusion of being "some body"...
After one full day of expression of my "illusory mental building" I had no definition left, nothing about myself I could cling to, I could not say what or who I was anymore, I tried hard but the only answer that came to me was "I don't know".And the funny thing was that my partner also reached the same AHA at the same time...And we started tlaughing without reason. It was a very deep laugh, without subject nor object, a really cosmic laugh that lasted long : I did not know who I was but I was...I did not need to know who I AM but my I AMness was Laughing without my will in a state of total lightness and freedom...