[filleduchaos]

> Is your arm part of your body?

Of course yes.

> Your hair?

Of course yes.

> A wig?

Of course not.

> A pacemaker?

Depends on who's asking and why.

> A well-fitted mechanical exoskeleton that you use without thinking about it? A poorly-fitted exoskeleton that you're still learning how to use?

Of course not to both of these things.

> A Jeep?

Of course not, and framing a Jeep and a human's liver as if the only possible point of difference between them is whether or not you can "feel" them is strange.

Half of us are fully capable of growing an entire other human being within our bodies, with a physical connection so tightly integrated that breaking it causes bleeding for weeks - and yet it's debatable whether even that counts as being a part of our bodies (especially medically speaking). Navel-gazing about the distinction between your body and a car not being clear-cut is simply inane to me in comparison.

[feoren]

So your definition seems to be that it's part of your body if it was built via instructions in your inherited DNA? So tattoos are not part of your body, nor are the gut bacteria you were mostly born with (or their ancestors) and without which you would quickly die. Phlegm that you spit on the street is still part of your body? Your tears? What about clonal colonies and parthenogenesis? Do identical twins have the same body?

The point is, your "of course" is based on some "obvious" definition that always gets fuzzy at the edges. Someone else's "of course" is based on some equally valid and obvious definition that gets fuzzy in different ways at different edges. Don't act like everyone who doesn't think exactly like you is just pointlessly navel gazing. The pointlessness is in trying to have a clear definition at all, which saying "of course" implicitly assumes.

> and framing a Jeep and a human's liver as if the only possible point of difference between them is whether or not you can "feel" them is strange.

Good thing that's nowhere near what I said. I said "I can feel it" is obviously not a good criterion.

[filleduchaos]

> So your definition seems to be that it's part of your body if it was built via instructions in your inherited DNA?

I think you'll find discussions significantly more straightforward if you don't make up the other person's side of the conversation for them and run off tilting at windmills.

What part of the comment where I e.g. said that whether or not a pacemaker is considered part of your body "depends on who's asking and why" gave you the impression that I define body parts as being built by you? What part of my comment mentioned genetics at all?

By the by, tattoos are a modification to a part of your body (your skin) but are very much not a part of it (your immune system is literally constantly trying to get rid of them). And your gut microbiota is very clearly considered to be a _separate_ organism from you, with its relationship described in symbiotic terms.

[feoren]

> I think you'll find discussions significantly more straightforward if you don't make up the other person's side of the conversation

You never specified your "obvious" definition, so I had to reverse engineer it from your examples. I wouldn't have to make up your side of the conversation if you just actually said what it is. You're still using "obvious" and "clearly" as meaning obvious to you, based on every iota of experience you've ever had, but totally failed to justify why exactly your "obvious" opinions should be obvious to anyone else. Either you have a hard and fast definition that can definitively determine whether that thing is or is not part of a body, or it's not obvious. Unless your rule for determining whether something is part of a body is: "just ask filleduchaos, and he'll tell you whether it obviously is or obviously is not."

> And your gut microbiota is very clearly considered to be a _separate_ organism from you

"Very clearly" again. It's considered a separate organism because it has different DNA than your germ cells. But so do your mitochondria. So does a chimeric twin. Is a chimera "obviously one" or "obviously two" bodies? Tell me which one of those is so obvious that I'd be completely stupid to believe the other one, please. I suspect you'll say it's obviously one body, but then you have a problem with gut bacteria being obviously not part of your body.