A title this would be, had I the originality.

I recently posted about the meaning of life, or at least what it means to be alive.

I read a couple of articles in BoingBoing that built on this very interesting question, so, another post on the questions they raise.

A woman with a stopped heart following two heart attacks, hypothermia, no neurological function, rigor mortis, her skin started to harden and her fingers to curl in death, arrangements are being made to donate her organs... is she dead?

Perhaps she is, it depends on your definition of death. By the UK and US medical and legal definitions of death, she definitely is dead. And in that case, our definition of death includes the ability to be brought back from death (whether by the work of Man or God), even at this late stage. Because, it just happenned. http://www.newsnet5.com/health/16363548/detail.html

Death isn't necessarily permanent, then? Grey areas like that make life fun!


But there's another article that is even more fun, and leads to even more thoughts. I'll explain in a sec, but first, some ground-thoughts.

With protozoa, one-celled organisms, telling what an individual is, is easy.

"When I need a friend I just give a wrinkle
split right down the middle
and pretty soon there's two of me
both as handsome as can be."
- The Incredible String Band

If it's a different cell, it's a different individual. I'll gloss over the fact that the exact moment when individuality strikes, exactly how many atoms can still be joined together and still call them the same cell, is maybe a little vague. Basically, it's quite clear.

With people, it's fuzzier. We instead generally count it by "cell lines". If something has your genes, it came from your original fertilised egg, and so it *is you*. Your hand is a part of you because it shares your genes. (There are grey areas. Identical twins, and animals which reproduce parthogenically, or by bifurcation, all share genes, and hence cell lines: but I'm ignoring these grey areas for the moment!)

Cancer cells in yourself are a part of you, since the tumour comes from your own cells, and is just malfunctioning.

Is a donated organ, say a hand, part of you? It is not from you, and not from your cell line. It is alive, given life support by your body, but is it not really still a part of the donor? If the donor is still alive, that sort of implies that people can be split into pieces and still be alive, in multiple places at once.

Which causes no problems for anyone, mentally... except theologians, if they believe in the concept of individuality, who then have to pick which organ contains the individual's soul (or self, spirit, individuality, etc). And then, if parts of that organ can die or be donated, which *cell* of that organ contains it, or else they need to deal with whether souls can be split up or not.

Anyway, this donated organ can grow and its cells can split and the stem cells from the marrow in its bones can go on to repair (infect?) any part of your body with not-you-derived cells. Over the course of a few years, every cell in your body is replaced, or so I read (I am skeptical, but I'll go with it for the sake of this question). If all the cells that make up the hand are replaced by those from your own bone marrow's stem cells, does the hand become "part of you", if it was not before?

What if someone were given bone marrow transplant, so that all their stem cells now came from someone else's genetic stock? In a few years, would they be someone else, once all their cells came, not from a combination of their own parents' genes, but from the donor's?

Women are apparently often (always, to some extent?) chimeras, made up of multiple cell lines, and are much more prone to this than men. This causes birthmarks; complications in pregnancy where one part of the body is allergic to the child that another created; complications figuring out parenthood (if you take a sample from the woman that is from a different cell line than the ovary that created the egg, then parenthood may not be established); and so on. But we have no problem saying that women are individuals, and are only one being, not multiple ones.

And then I find that some (very few) cancers can be sexually transmitted! Which quietly blew my mind. Because, you see, cancers are special. Unlike the hand, we *know* that every cell in a cancer split from itself. It is always from the original host's cell line.

So the oldest living mammal cell line... the oldest living mammal, by some definition... is a sexually transmitted disease for dogs.