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Comment by matt_morgan | Hacker News Reader

It should really be called a "body transplant."

From the article:

(Technically, the surgery would be a body transplant, since the acquisition of a new body is what saves the patient’s life. Then again, the head makes up less than 10 percent of our body weight. Can you really “transplant” the heavier, majority part? And if rejection occurs, it will be the body rejecting the head, not vice versa.)

This reminds me of an old joke: The doctor has a patient come in, and is startled to realise he has a live frog sticking out of his forehead. "Good lord, how did you end up with that?" the doctor asks. "Well, it started as a zit on my ass," replies the frog.

The article does mention that, but I don't think simply defining the base of the transplant as the section with the most mass accurately describes the situation. What part of the body defines a person's identity? Is it the head, or the rest of the body? I can see a case where the brain is considered the center of mass (from an operation standpoint).

Going by center of mass means that for a sufficiently large tumor, you'd be talking about a patient-ectomy.

I think that underscores the point about flexibility in naming operations ;)

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!

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.

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

They also discard the body of the heart donor.

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

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.

> 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?

Which part stops talking to you, if it loses consciousness and slips into a coma?

That's the part that sues you for malpractice.

At that point, isn't the question whose family sues you for malpractice?

Only if it stays in the coma.

Doesn't it come down to what can be exchanged and retain jwn?

jwn's head on a different body may be taller and slimmer, but the personality remains. It should, in essence, still be "you". Vice versa and we get a completely different person but with about your height and build.

So on that basis I think I prefer to think of body transplant to head transplant.

...maybe. I think we underrate the physicality of our minds. For example, if you transplanted a male head on a female body or vice versa, some personality changes would be expected. Or a male head on a male body with different testosterone levels, for example.

Hm. Never considered a gender swap body, but it raises some interesting questions.

While I agree with you agree with your general argument from an abstract and pedantic point of view, OTOH, I think "head transplant" is a lot cleaner and more convenient to use than "all-of-the-body-except-the-head transplant", without any loss of clarity in practical communication.

At some point, you have to accept that language is meant to be used, and that's more important than being abstractly consistent.

The head is part of the body, so, no; "All-of-the-body-except-the-head" would be accurate, but overly cumbersome. Given that people know that the seat of identity is in the head, "head transplant" fairly obviously in practical use means "all-of-the-body-except-the-head transplant", but is a lot easier to say.

Going completely off topic, but when I heard the title, the initial picture I saw, was a body, with a failing head, being saved by the addition of functional head from the recently deceased.

After a few seconds, I remembered "the seat of identity is in the head" and I corrected the image. Anyway, for all of us reading the news before our morning coffee kicks in, I have to say that "body transplant" would more quickly convey what's actually happening.

I've read that the transplant can be defined through what part has to be kept alive during the procedure. So when you're transplanting a heart, there is a brief period where the heart is without a body to support it - ergo heart transplant.

I think the same applies here.

But a body without heart or head doesn't live by itself either.

A true Body of Theseus problem.

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