“Enq: The materialist, disbelieving in everything that cannot be proven to him by his five senses, or by scientific reasoning, based exclusively on the data furnished by these senses in spite of their inadequacy, and rejecting every spiritual manifestation, accepts life as the only conscious existence.
Therefore according to their beliefs so will it be unto them. They will lose their personal Ego, and will plunge into a dreamless sleep until a new awakening. Is it so?
Theo: Almost so. Remember the practically universal teaching of the two kinds of conscious existence: the terrestrial and the spiritual.
The latter must be considered real from the very fact that it is inhabited by the eternal, changeless and immortal Monad; whereas the incarnating Ego dresses itself up in new garments entirely different from those of its previous incarnations, and in which all except its spiritual prototype is doomed to a change so radical as to leave no trace behind.
Enq: How so? Can my conscious terrestrial “I” perish not only for
a time, like the consciousness of the materialist, but so entirely as to leave no trace behind?
Theo: According to the teaching, it must so perish and in its fullness, all except the principle which, having united itself with the Monad, has thereby become a purely spiritual and indestructible essence, one with it in the Eternity.
But in the case of an out-and-out materialist, in whose personal “I” no Buddhi has ever reduced itself, how can the latter carry away into the Eternity one particle of that terrestrial personality?
Your spiritual “I” is immortal; but from your present self it can carry away into Eternity that only which has become worthy of immortality, namely, the aroma alone of the flower that has been mown by death.
Enq: Well, and the flower, the terrestrial “I”?
Theo: The flower, as all past and future flowers which have blossomed and will have to blossom on the mother bough, the Sutratma, all children of one root of Buddhi – will return to dust.
Your present “I”, as you yourself know, is not the body now sitting before me, nor yet is it what I would call Manas-Sutratma, but Sutratma-Buddhi.”
H. P. Blavatsky
The Mark Of God: Understanding Your "I AM Presence" 