Tor Nørretranders, from the Edge's latest annual question, "What have you changed your mind about? Why?":

98 percent of the atoms in the body are replaced every year. 98 percent! Water molecules stays in your body for two weeks (and for an even shorter time in a hot climate), the atoms in your bones stays there for a few months. Some atoms stay for years. But almost not one single atom stay with you in your body from cradle to grave.

What is constant in you is not material. An average person takes in 1.5 ton of matter every year as food, drinks and oxygen. All this matter has to learn to be you. Every year. New atoms will have to learn to remember your childhood.

These numbers has been known for half a century or more, mostly from studies of radioactive isotopes. Physicist Richard Feynman said in 1955: "Last week's potatoes! They now can remember what was going on in your mind a year ago."

I love this. First of all, it's exactly the sentiment I was trying to get across in my poem, "The Stygian Depths of You and I and All." Secondly, "Last Week's Potatoes" is tremendous name for a band.