People have had just about all major organs south of the brain replaced individually by either machines or biological transplants. (Can anyone identify one that hasn't?) And I don't think anyone's ever seriously claimed that such people have had their identity changed in any meaningful sense. Unless you have a very complicated hypothesis about multiple organs in the abdomen effecting personality in a weird redundant way--where losing one of them doesn't change your identity but loosing many does--the evidence is overwhelming that everything we think of as "identity" is in the brain.

Of course various hormones change personality traits, and many of those are governed or heeded below the neck. Trivially, testosterone.

I think you underestimate the effect body changes can have on one's identity. "identity change due to trauma" will find you plenty to think about, for example http://www.centerforpos.org/Positive/POS-Research/Papers/Pap... "Matthew, a professional ‘cellist, damaged two tendons in his shoulder. […] he felt “a kind of total emptiness and utter exhaustion that really was literally sapping my will to live.” At the centre of this emptiness lay the question, “Who am I now?""

http://biomed.brown.edu/Courses/BI108/BI108_2003_Groups/Hand...: "In addition, assessments should be made of their body-image adaptation after amputation, impact of amputation on their identity and relationships"

http://www.athealth.com/consumer/disorders/traumaeffects.htm...: "Survivors may have problems with identity when PTSD symptoms change important aspects of a person's life such as relationships or whether the person can do his or her work well."

http://www.nbmtlink.org/resources_support/spg/spg_appearance...: "Every time I look in the mirror, I see someone different than the person I knew during my life before transplant."

Is all of that in the brain? In some sense: yes, but bodily changes do change how you think about yourself, and that is one definition/aspect of 'personality' (http://en.wikipedia.org/wiki/Identity#Personal_conception_an...)

All of these effects are smaller and of the same type as you might get from life events (like PTSD, or divorce). But that doesn't mean that "you are your marriage" in anything like the same sense as "you are your brain".

I don't disagree, and I'm excited about these new developments - but continuity-of-consciousness would continue even if I had my bowel ripped out. This is not the case if I had my brain ripped out.

On the other hand, people with radical brain surgery still think they're the same person, putting aside cases like Phineas Gage.

On the gripping hand, even though transferring my brain and its shell to a different body will still maintain my memories, and continuation-of-consciousness and transferring everything neck-down won't, if the person with my guts-and-spleen acts more like me, and the person with my head on their shoulders acts more like the guy whose anus it's attached to acts more like them, perhaps it could be said that we really did switch, despite the memories.