One part of the God Delusion asks that we be amazed that somewhere in our body is an atom of Oliver Cromwell's bathwater. Another part asks us to be amazed that there is not an atom of our being that was in us when we were a kid is in us today.
I call shenanigans. I don't have something of me from when I was a kid, but I have some of Oliver Cromwell? My ass. Some of my water could have been expelled gone around the planet and be in me again today.
There's a lot of atoms in me, a lot, clearly the latter statement is flawed or the former. If the laws of statistics gives me an atom of Oliver Cromwell it gives me an atom of me.