When people conceive of a life after death and a subsequent rebirth, they almost invariably overlay their current life, personality and circumstances over that conception. They thus tend to believe that the same “I” that they recognise in this lifetime somehow is going to be consistent and identifiable in future lifetimes. “John Smith” today is “John Smith” in some future lifetime as well, carrying on a consistent story-line, with the one that we experience today. This however is not a realistic nor logical conclusion about the functioning of the process of rebirth, the law of karma, or the evolutionary cycle of development. Sri Aurobindo explains: “For the growth of the embodied being towards the full stature of its reality, not only a new experience, but a new personality is indispensable; to repeat the same personality would only be helpful if something had been incomplete in its formation of its experience which needed to be worked out in the same cadre of self, in the same building of mind and with the same formed capacity of energy.” If this were to occur, however, “Our life and rebirth would be always the same recurring decimal; it would be not an evolution but the meaningless continuity of an eternal repetition. Our attachment to our present personality demands such a continuity, such a repetition; John Smith wants to be John Smith for ever: but the demand is obviously ignorant and, if it were satisfied, that would be a frustration, not a fulfilment. It is only by a change of outer self, a constant progression of the nature, a growth in the spirit that we can justify our existence.”
Sri Aurobindo, The Life Divine, Book 2, Part 2, Chapter 22, Rebirth and Other Worlds; Karma, the Soul and Immortality