Stem Cells Again
The debate continues.

By Ronald Bailey, Reason magazine’s science correspondent
August 20, 2001 9:35 a.m.

atrick Lee and Robert P. George claim that my arguments for the morality of using stem cells derived from human embryos to treat patients have "collapsed" in the face of their analysis. Let's review briefly what this exchange has been about. The central question is are embryos, from which stem cells derived, are people? If they are people then they have intrinsic moral worth and it would be evil to kill them for the purpose of benefiting other people.

First, in characteristic move, Lee and George claim that I have "shifted" my arguments when in fact what I have done in each article is marshal additional evidence to show that embryos are not people. In their latest critique, they erroneously insist that I am defining human beings in terms of their being conscious or having "mental functions." Weirdly, Lee and George apparently think the fact that the brain dead no longer have thoughts, memories, emotions, or intentions, is a philosophical claim — actually it's just a medical fact. I cited the example of brain death simply to point out that the brain dead are not people and that we do therefore find it morally laudable to use their still living organs, donated either by prior bequest or by consent of next of kin, to cure patients. The brain dead don't have functioning brains, therefore they are not people. Embryos consisting on 100 or so undifferentiated cells, don't have brains, therefore they also are not people. The bright moral line is the presence or absence of a more or less working brain.

In their most recent installment in our ongoing discussion, Lee and George turn to embryology textbooks seeking support for their argument that embryos are human embryos. Well yes, they certainly do find that the textbooks declare human embryos to be human embryos, they clearly aren't dog embryos or cat embryos. However, what we are trying to determine is whether or not human embryos are people. It is assuredly the case that human DNA is required for an entity to qualify, but clearly that is not sufficient since every skin cell, every nerve cell, nearly all cells in your body contains human DNA which is why we look for additional criteria for defining people.

So, again, another thing we know for sure is that people all have human brains. So a test suggests itself, if beings have a more or less functioning ("more or less" because with regard to the possibility of doing evil, we want to err on the side of caution) human brains, then we have identified people. Conversely, if an they do not have more or less functioning human brains, then they are not people.

It is also curious that Lee and George are now citing embryology texts as though they were somehow analogous to the eternal verity of scripture, when the point of the discussion is that those texts are being revised in light of new scientific information, in particular in light of cloning which logically, if not yet logistically, could turn every cell in your body into your twin. Of course, new scientific information is not dispositive, but surely in this case it sheds light on the moral questions with which we must grapple.

In their latest critique, Lee and George assert that they have "argued that human beings have intrinsic, and not merely instrumental, value. Each of us has worth because of what we are, not because of the properties or states that we happen to instantiate." Where's the argument — I agree. Despite their mischaracterization of my arguments, we are not arguing over "properties or states that we happen to instantiate" we are arguing over whether embryos are people or not. To reiterate, people must have functioning brains, they are not just entities containing human DNA.

Lee and George assert that "[p]eople do not acquire worth, dignity, and basic rights only after coming to be." Agreed. People have worth, dignity, and basic rights, however, embryos aren't people.

Lee and George achieve an apogee in twisted logic when they falsely claim that I said in my most recent discussion that identical twins were not distinct individuals because they have the same genomes. Of course they are distinct — that is why I brought twins up in the first place. Lee and George completely miss, ignore, or misunderstand the point that identical twins prove that being distinct individuals does not depend on having the same genetic makeup, being distinct has everything to do with having separate brains. I'm sure that they must know this and so conclude that somehow they misread my arguments.

Using interesting and telling bits of word play, Lee and George, try to slur over the inconvenient facts that identical twins and chimeric indviduals undermine their arguments for the distinctness of embryos. They suggest in twinning "another distinct, living human individual is generated from the cells of an already extant embryonic human being, through extrinsic division." But doesn't "distinct" mean different, separate? Monozygotic twinning shows embryos are at some stage not "distinct" individuals, they can become two individuals at some later stage. Even more interesting is their strange characterization of what happens when two embryos combine in a womb to form one individual. They write "one twin dies and his cells become part of the other twin." Died? No, neither ceased living. What happens is that allegedly "distinct" embryos join into one individual.

Lee and George persist in trying to draw artificial lines in what is now known to be a continuum of potential development. Any human cell could, when combined with factors from egg cytoplasm, begin the process of embryonic development. It is true that it takes the "proper environment," as Lee and George say, for an embryo to develop, but it's also true that all it takes for any human cell to begin the process of develop is the proper environment and one of the necessary proper environments is egg cytoplasm. Lee and George in order to try to get around the problem that human DNA in the proper environment begins embryonic development, engage in a bit of verbal slight of hand, by redefining egg cytoplasm as a "co-principle" which is incorporated into the growing cell. If it's a co-principle, runs their argument, then it can't be environment. (I don't know for sure, but I doubt that standard embryology texts have much to say about such "co-principles.") Environment generally means "that which surrounds" — human DNA surrounded by egg cytoplasm begins embryonic development. So what we see is that there is a series of proper environments needed for human DNA to begin the process of embryonic development. Any one of them being absent, development fails.

Finally, Lee and George quibble over whether an estimate that I cited that as many as 80% of embryos naturally do not implant is too high. (See O'Rahilly R, Müller F. Human Embryology & Teratology. New York, NY: Wiley-Liss; 1992:56 for the 80% estimate.) Instead, they prefer to cite 45% as the "standard" estimate. Fine. Then they suggest that half of those are "the results of incomplete fertilizations." Again, fine. The plain fact is still that millions of viable embryos each year produced via normal conception still fail to implant and are shed in women's normal menstrual flow. Thus I asked in my earlier response: "Given Lee and Patrick's insistence that every embryo is "already a human being," does that mean that if we could detect unimplanted embryos as they leave the womb, we would then have a duty to rescue them and try to implant them anyway? Furthermore, do we mourn the deaths of these millions of embryos as we would the death of child?"

In reply, Lee and George strangely call our attention to the high infant death rate of past centuries. First, I remind readers we are not talking about infants, infants are people and even in past scientifically bereft centuries, they were people. Second, I believe that in past centuries the deaths of infants were mourned. Maybe what Lee and George are suggesting is that since we have a duty to rescue infants, then we do have a duty to rescue normal 5-day-old unimplanted embryos. If that's the case, why don't they just say so instead of hinting coyly at that conclusion? Perhaps because they know that if people actually think about that proposition a bit, that they will reasonably conclude that embryos are not people. The fact is that we do not rescue unimplanted embryos, nor mourn them because we do know that they are not people.