Mystics would tell you, you are not your body - materialists would tell you, you are only your body - whereas the existential fact of human life is that, you are not your body - you are not your mind - you are nothing - for there is nothing constant about you at any given moment that you can say that you are that - your mind is constantly changing - your body is constantly changing - you as a bio-psychological creature are constantly evolving - if there is anything that's constant about you, it's change itself - therefore, what you really are, is an eternal force of change.