I meant to say something about this National Review column by Patrick Lee and Robert P. George, which takes our very own Ron Bailey as one of its foils, when it first appeared a few weeks ago, but there's a truly impressive amount of silliness to slog through. The piece attempts to respond to an argument in the debate over the moral status of embryos—a reductio of the hard "from the moment of conception" position—that I've offered myself from time to time: As cloning technology advances, every cell in the human body, placed in the right sort of environment, will be a potential human being. If not just embryos with semi-developed nervous systems but blastocysts a few days after conception are supposed to be treated as persons (the argument runs), then aren't we pushed to the absurd conclusion that every human cell must be treated in the same way?
Lee and George begin by burning quite a few pixels emphasizing that they don't regard embryos as "potential" persons, but rather as already persons at an early stage of development. But that doesn't actually get you anywhere: Insofar as "potential" still plays a role in the argument, because it's still the rational nature of human beings (which is to say, the kind of thing the blastocyst typically turns into) that distinguishes them morally, you've got the parallel question of why that loose skin cell isn't also an actual human being "at an early stage of development."
So the meat of the argument has to do with distinguishing that blastocyst from any other somatic cell…and the argument appears to consist in the copious use of italics. That is, the authors seem to think that if they point out that a blastocyst develops into an infant through a self-directed process, they can make that self-directed an interesting or morally relevant fact by sheer force of typeface. Even granting the notion that the embryo has an "active disposition" to become a grown person that the somatic cell lacks, it's never made clear why anything is supposed to hang on that distinction. Presumably it's got something to do with their claim that dropping the somatic cell's genetic information (which, unlike that in a gamete, is the full set required to make a new person) into an enucleated ovum creates a "new and distinct substantial entity." But this is just question begging and table pounding. While George and Lee manage to resist what must be the ever-present temptation to fall back on medieval talk of quiddities, there's no way to make sense of this argument without some rather queer metaphysical view about how the shift from a "passive" to an "active" potentiality (as accomplished by somatic cell nuclear transfer) creates a distinct entity with a distinct essence in some way that no other step in the maturation process does.
Actually, this is all too charitable so far: It's not even clear that this active/passive distinction can be cashed out in any terribly interesting way. Obviously, an ordinary somatic cell is going to require significant human assistance to turn into a little Timmy or Suzy. But that's also true of the embryo: If it's created in vitro, you've got to deposit it in a suitable environment (that is, a natural or artificial womb), and once it's there, you've got to keep a steady flow of nutrients and other building materials coming in order for the process to unfold. It's not at all obvious that the difference between a "passive" and an "active" disposition can really be specified intelligibly.
Finally, the authors whip out the italics again to argue that the radical moral difference between entities that have rights and entities that don't must correlate with some kind of radical ontological difference, in this case having some kind of special nature or essence, rather than "accidental" traits like rationality or self-consciousness, which exist along a gradient. But this is wrong at both ends. First, the moral status of different sorts of entities is also in many ways a matter of degree: Children and the severely mentally retarded have rights, but not all the same rights we afford more fully rational adult humans. And while most people don't regard non-human animals as having "rights" per se, most people will probably agree that there's at least something morally wrong with, say, torturing a chimpanzee or a dog for no good reason. Second, it's not obvious that there's some bright line, either-or property (unless we go hunting for those quiddities) that corresponds to "having the nature of a rational human being." There's about a 2 percent difference between human and chimp DNA; if we tweak one base pair at a time along the path from the former to the latter, what's the magic point at which some kind of embryonic transubstantiation imbues the cells we're tweaking with a human essence? Biologists, of course, use ability to reproduce as the criteria for distinct species populations, but that obviously won't do for any particular organism, which might for any number of reasons be unable to reproduce without calling into question its species membership.