there are always new atoms, but always doing the same dance

"To note that the thing I call my individuality is only a pattern or dance, that is what it means when one discovers how long it takes for the atoms of the brain to be replaced by other atoms. The atoms come into my brain, dance a dance, and then go out -- there are always new atoms, but always doing the same dance, remembering what the dance was yesterday."

http://news.ycombinator.com/item?id=377751