“Enq: But what is the distinction between this “true individuality” and the “I” or “Ego” of which we are all conscious?
Theo: Before I can answer you, we must argue upon what you mean by “I” or “Ego”. We distinguish between the simple fact of self-consciousness, the simple feeling that “I am I”, and the complex thought that”I am Mr. Smith” or “Mrs. Brown”.
Believing as we do in a series of births for the same Ego, or reincarnation, this distinction is the fundamental pivot of the whole idea.
You see “Mr. Smith” really means a long series of daily experiences strung together by the thread of memory, and forming what Mr. Smith calls “himself”. But none of these “experiences” are really the “I” or the Ego, nor do they give “Mr. Smith” the feeling that he is himself, for he forgets the greater part of his daily experiences, and they produce the feeling of Egoity in him only while they last.
We Theosophists, therefore, distinguish between this bundle of “experiences”, which we call the false (because so finite and evanescent) personality, and that element in man to which the feeling of “I am I” is due.
It is this “I am I” which we call the true individuality; and we say that this “Ego” or individuality plays, like an actor, many parts on the stage of life. (Vide infra, “On Individuality and Personality”)
Let us call every new life on earth of the same Ego a night on the stage of a theatre. One night the actor, or “Ego”, appears as “Macbeth”, the next as “Shylock”, the third as “Romeo”, the fourth as “Hamlet” or “King Lear”, and so on, until he has run through the whole cycle of incarnations.
The Ego begins his life-pilgrimage as a sprite, an “Ariel”, or a “Puck”; he plays the part of a super, is a soldier, a servant, one of the chorus; rises then to “speaking parts”, plays leading roles, interspersed with insignificant parts, till he finally retires from the stage as “Prospero”, the magician.”
H. P. Blavatsky
The Mark Of God: Understanding Your "I AM Presence" 