¿WHO ARE YOU? NO, REALLY ¿WHO ARE YOU?

 This is something to think about who we are, but seen from a different level and perspective. Published originally at news.bbc.co.uk.
It makes you ponder indeed.

Consider a photo of someone you think is you eight years ago. What makes that person you? You might say he she was composed of the same cells as you now. But most of your cells are replaced every seven years. You might instead say you're an organism, a particular human being, and that organisms can survive cell replacement - this oak being the same tree as the sapling I planted last year. 

Are you really an entire human being? If surgeons swapped George Bush's brain for yours, surely the Bush look-alike, recovering from the operation would be you. Hence it is tempting to say that you are a human brain, not a human being.
In the end, then, no attempt to make sense of your continued existence over time works. You are not the person who started reading this article.