Are 'you' your flesh, your physical form? If so, would 'you' still exist if all your fleshy parts were incrementally replaced until you were wholly something artificial? Would you still be a person? Are 'you' your sentient mind, your own self-consciousness? If you brain, or whatever system we were left with from the above experiment were to be split in two in such a matter than each half functioned independently and was self-aware, would 'you' still exist, or would 'you' cease to exist as we were left with two new 'persons'? What makes one a person? What makes a person an individual?