Wm: This is a bit creepy…

Oh, okay; I think I can read this as saying that you’d find it a little suspicious (perhaps “a little too convenient”). I misunderstood before — I thought you were saying that you’d never expect them to do something like that. Yeah, I’d take it in stride… There’s only one thing I don’t expect from the modern Catholic Church, and that thing _nobody_ expects anyhow.

chaospet: okay, I dig that. And I do agree that it’s very important to dig away at the boundaries.

Huh. This isn’t supposed to happen. I’m not used to agreeing with you.

-Wm

I know you don’t. Neither do I. As Canuovea says, the comic is just making a conditional claim: if you say that zygotes are people, then chimeras create substantial puzzles for you.

Again, though we lack a precise definition of personhood, I think we obviously do have a strong sense of how to differentiate people in ordinary circumstances on the basis of things like psychological traits. And indeed, it is very common in the debate over criteria of personhood to appeal to this intuitive sense of what counts as a person for counterexamples. For instance, when John Locke says that personhood and personal identity is all about memory, we come up with all sorts of counter-intuitive results that challenge the idea. Such examples don’t strictly disprove Locke’s account, but they do provide some reason to question it and search for a more viable alternative.

My suggestion is only that the revelation that tetragametic chimeras exist, that two zygotes can fuse and develop into a single entity, plays the same sort of role in creating a challenge for those who think personhood requires nothing more than a sperm and egg cell fusing to form a full set of DNA.