This post is filed under "morality" because the question "Which parts of my brain are 'me'?" is a moral question - it's not predicted so much as chosen. You can't perform a test on neural tissue to find whether it's in or out. You have to accept or reject any particular part, based on what you think humans in general, and yourself particularly, ought to be.
Read the whole thing, and follow some of the hyper-links. And read the comments, which contain such gems as:
I'm depressed about the coming end of the human race. Got a solution for that? :-)
Posted by: MichaelG | October 22, 2008 at 03:07 PM
Yeah, shut up and save the world.
Posted by: Eliezer Yudkowsky | October 22, 2008 at 03:18 PM
Which is funnier because he means it, and already he's written several good arguments for it. Seriously: this should be required reading for the entire human race.