Let's say I'm a mad neuroscientist who successfully alters the structure of a
Yes. Of course, I only think that because I think personal identity depends on continuity of memory and character traits, and I think memory and character traits are constituted by brain states. So, if you could somehow alter my brain enough to wipe out my memories (perhaps replacing them with some artificial set of memories) and change my character traits, you will have killed me. And if you did it knowingly and purposely, you have committed murder (i.e., the intentional killing of a person). But...
1. I'm not sure how our legal system would deal with it. I suspect there's something in our murder statutes that requires a dead body for a murder charge. We'd have to get our laws up to date with our science (and philosophy!).
2. Now, I've opened the door to some slippery slopes (or sorites arguments). How much of my identity does an evil neuroscientist have to mess up before he kills me. If he deletes 50% of my memories and changes half my character traits, has he killed me (killed half of me?)? What about 90%? Of course, real-life brain damage or disorders, such as amnesia, Alzheimer's, and vegetative states, raise similar questions about when a person passes away, even if the body hasn't.