'Who am I?' The answer is 'I am God'. The body comes and goes, but the Atma is permanent. The body has birth and death, but the spirit does not have any of these. You reach the stage where you say, 'I am God', but even there, there is duality, 'God and I'. That is not the full Truth. When we breathe, the breath makes the sound of 'So-Hum', 'He am I'. There is still the body consciousness, the 'I'. But in deep sleep, the declaration of 'He' and 'I' falls away and only '0' and 'M' remain, 'Om'; there is only the One.