[cthulhujr]

Can it be defined as what is being replaced and discarded? When you have a heart transplant, they replace the heart with a new one and discard the old heart. In this case, they're discarding the body, so I see it as a body transplant. As others have noted, mass is meaningless in this context.

Edit: The sources on wikipedia's https://en.wikipedia.org/wiki/Head_transplant article all call it a head transplant... so, I assume people more knowledgeable than I on the topic have already "talked it out". Head transplant it is!

[StavrosK]

That's exactly my view as well. You don't have a "body minus liver" transplant, you have a liver transplant (i.e. you get a new liver). Here, you get a new body, not a new head, therefore body transplant.

[matt_morgan]

I like that; and I like defining it as what part goes with the self. Your definition is probably cleaner but I think most of us feel like the "I" goes with the head no matter what else may change.

[leni536]

> Can it be defined as what is being replaced and discarded?

From the viewpoint of the patient? Which person is the donor and which is the patient?

[danilocesar]

They also "discard" the dead head... So, I guess no.

[justinlardinois]

What's discarded from the donor doesn't really mean much. We don't consider what parts of organ donors' bodies aren't used.

[cthulhujr]

They also discard the body of the heart donor.