QOTD: The potential for personhood

Quote of the Day:

Yes, Mr Barnard began as a zygote. That does not mean the zygote was Mr Barnard. My car began as a stack of metal ingots and barrels of plastics; that does not imply that an ingot of iron is a car. My house began as a set of blueprints and an idea in an architect's mind; nobody is going to pay the architect rent for living in his cranium or on a stack of paper in a cabinet. The zygote was not Justin Barnard, unless Justin Barnard is still a vegetating single-celled blob, in which case I'd like to know how he typed his essay.

Since Barnard claims to be a philosopher, I'll cite another, a guy named Aristotle. This is a quote I use in the classroom when I try to explain to them how epigenesis works, in contrast to preformation. Aristotle did some basic poking around in chicken eggs and in semen, and he noticed something rather obvious—there were no bones in there, nor blood, nor anything meatlike or gristly or brainy. So he made the simple suggestion that they weren't there.

Why not admit straight away that the semen…is such that out of it blood and flesh can be formed, instead of maintaining that semen is both blood and flesh?

Barnard is making the classic preformationist error of assuming that everything had to be there in the beginning: I am made of bones and blood and flesh and brains and guts and consciousness and self-identity, therefore the zygote must have contained bones and blood and flesh and brains and guts and consciousness and self-identity.

It didn't.

Why not admit straight away that the zygote is such that out of it selfhood may arise, rather than maintaining that the zygote is the self?

In that case we have to recognize that the person is not present instantaneously at one discrete moment, but emerges gradually over months to years of time, that there were moments when self was not present and other moments when self clearly was present, and moments in between where there is ambiguity or partial identity or otherwise blurry gray boundaries. This is a conclusion that makes conservative ideologues wince and shy away — I think it's too complicated for their brains, which may in some ways be equivalent to the gormless reflexive metabolic state of the zygote — but it is how science understands the process of development. - PZ Myers