Billions & Billions

by Carl Sagan

  By far the most common reason for abortion worldwide is birth control. So shouldn’t opponents of abortion be handing out contraceptives and teaching school children how to use them? That would be an effective way to reduce the number of abortions. Instead, the United States is far behind other nations in the development of safe and effective methods of birth control—and, in many cases, opposition to such research (and to sex education) has come from the same people who oppose abortions.†

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  The attempt to find an ethically sound and unambiguous judgment on when, if ever, abortion is permissible has deep historical roots. Often, especially in Christian tradition, such attempts were connected with the question of when the soul enters the body—a matter not readily amenable to scientific investigation and an issue of controversy even among learned theologians. Ensoulment has been asserted to occur in the sperm before conception, at conception, at the time of “quickening” (when the mother is first able to feel the fetus stirring within her), and at birth. Or even later.

  Different religions have different teachings. Among hunter-gatherers, there are usually no prohibitions against abortion, and it was common in ancient Greece and Rome. In contrast, the more severe Assyrians impaled women on stakes for attempting abortion. The Jewish Talmud teaches that the fetus is not a person and has no rights. The Old and New Testaments—rich in astonishingly detailed prohibitions on dress, diet, and permissible words—contain not a word specifically prohibiting abortion. The only passage that’s remotely relevant (Exodus 21:22) decrees that if there’s a fight and a woman bystander should accidentally be injured and made to miscarry, the assailant must pay a fine.

  Neither St. Augustine nor St. Thomas Aquinas considered early-term abortion to be homicide (the latter on the grounds that the embryo doesn’t look human). This view was embraced by the Church in the Council of Vienne in 1312, and has never been repudiated. The Catholic Church’s first and long-standing collection of canon law (according to the leading historian of the Church’s teaching on abortion, John Connery, S.J.) held that abortion was homicide only after the fetus was already “formed”—roughly, the end of the first trimester.

  But when sperm cells were examined in the seventeenth century by the first microscopes, they were thought to show a fully formed human being. An old idea of the homunculus was resuscitated—in which within each sperm cell was a fully formed tiny human, within whose testes were innumerable other homunculi, etc., ad infinitum. In part through this misinterpretation of scientific data, in 1869 abortion at any time for any reason became grounds for excommunication. It is surprising to most Catholics and others to discover that the date was not much earlier.

  From colonial times to the nineteenth century, the choice in the United States was the woman’s until “quickening.” An abortion in the first or even second trimester was at worst a misdemeanor. Convictions were rarely sought and almost impossible to obtain, because they depended entirely on the woman’s own testimony of whether she had felt quickening, and because of the jury’s distaste for prosecuting a woman for exercising her right to choose. In 1800 there was not, so far as is known, a single statute in the United States concerning abortion. Advertisements for drugs to induce abortion could be found in virtually every newspaper and even in many church publications—although the language used was suitably euphemistic, if widely understood.

  But by 1900, abortion had been banned at any time in pregnancy by every state in the Union, except when necessary to save the woman’s life. What happened to bring about so striking a reversal? Religion had little to do with it. Drastic economic and social conversions were turning this country from an agrarian to an urban-industrial society. America was in the process of changing from having one of the highest birthrates in the world to one of the lowest. Abortion certainly played a role and stimulated forces to suppress it.

  One of the most significant of these forces was the medical profession. Up to the mid-nineteenth century, medicine was an uncertified, unsupervised business. Anyone could hang up a shingle and call himself (or herself) a doctor. With the rise of a new, university-educated medical elite, anxious to enhance the status and influence of physicians, the American Medical Association was formed. In its first decade, the AMA began lobbying against abortions performed by anyone except licensed physicians. New knowledge of embryology, the physicians said, had shown the fetus to be human even before quickening.

  Their assault on abortion was motivated not by concern for the health of the woman but, they claimed, for the welfare of the fetus. You had to be a physician to know when abortion was morally justified, because the question depended on scientific and medical facts understood only by physicians. At the same time, women were effectively excluded from the medical schools, where such arcane knowledge could be acquired. So, as things worked out, women had almost nothing to say about terminating their own pregnancies. It was also up to the physician to decide if the pregnancy posed a threat to the woman, and it was entirely at his discretion to determine what was and was not a threat. For the rich woman, the threat might be a threat to her emotional tranquillity or even to her lifestyle. The poor woman was often forced to resort to the back alley or the coat hanger.

  This was the law until the 1960s, when a coalition of individuals and organizations, the AMA now among them, sought to overturn it and to reinstate the more traditional values that were to be embodied in Roe v. Wade.

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  If you deliberately kill a human being, it’s called murder. If you deliberately kill a chimpanzee—biologically, our closest relative, sharing 99.6 percent of our active genes—whatever else it is, it’s not murder. To date, murder uniquely applies to killing human beings. Therefore, the question of when personhood (or, if we like, ensoulment) arises is key to the abortion debate. When does the fetus become human? When do distinct and characteristic human qualities emerge?

  We recognize that specifying a precise moment will overlook individual differences. Therefore, if we must draw a line, it ought to be drawn conservatively—that is, on the early side. There are people who object to having to set some numerical limit, and we share their disquiet; but if there is to be a law on this matter, and it is to effect some useful compromise between the two absolutist positions, it must specify, at least roughly, a time of transition to personhood.

  Every one of us began from a dot. A fertilized egg is roughly the size of the period at the end of this sentence. The momentous meeting of sperm and egg generally occurs in one of the two fallopian tubes. One cell becomes two, two become four, and so on—an exponentiation of base-2 arithmetic. By the tenth day the fertilized egg has become a kind of hollow sphere wandering off to another realm: the womb. It destroys tissue in its path. It sucks blood from capillaries. It bathes itself in maternal blood, from which it extracts oxygen and nutrients. It establishes itself as a kind of parasite on the walls of the uterus.

  A human egg cell just after fertilization, partially surrounded by the runner-up sperm cells. The roughly 300 million also-rans have not yet arrived.

  A human embryo three weeks after conception, about the size of a pencil point, with head at the right. The segmentation extending to the tail resembles that of a worm.

  • By the third week, around the time of the first missed menstrual period, the forming embryo is about 2 millimeters long and is developing various body parts. Only at this stage does it begin to be dependent on a rudimentary placenta. It looks a little like a segmented worm.*

  • By the end of the fourth week, it’s about 5 millimeters (about ⅓ inch) long. It’s recognizable now as a vertebrate, its tube-shaped heart is beginning to beat, something like the gill arches of a fish or an amphibian become conspicuous, and there is a pronounced tail. It looks rather like a newt or a tadpole. This is the end of the first month after conception.

  • By the fifth week, the gross divisions of the brain can be distinguished. What will later develop into eyes are apparent, and little buds appear—on their wa
y to becoming arms and legs.

  A human embryo at the end of the fifth week after conception. The tail is curled under the leg buds. The face, seen here in profile, has a distinctly reptilian aspect.

  A 16-week-old fetus seems quite human externally. But it cannot yet move on its own enough to be detectable as “quickening,” nor can it survive outside the womb.

  • By the sixth week, the embryo is 13 millimeters (about ½ inch) long. The eyes are still on the side of the head, as in most animals, and the reptilian face has connected slits where the mouth and nose eventually will be.

  • By the end of the seventh week, the tail is almost gone, and sexual characteristics can be discerned (although both sexes look female). The face is mammalian but somewhat piglike.

  • By the end of the eighth week, the face resembles that of a primate but is still not quite human. Most of the human body parts are present in their essentials. Some lower brain anatomy is well-developed. The fetus shows some reflex response to delicate stimulation.

  • By the tenth week, the face has an unmistakably human cast. It is beginning to be possible to distinguish males from females. Nails and major bone structures are not apparent until the third month.

  • By the fourth month, you can tell the face of one fetus from that of another. Quickening is most commonly felt in the fifth month. The bronchioles of the lungs do not begin developing until approximately the sixth month, the alveoli still later.

  So, if only a person can be murdered, when does the fetus attain personhood? When its face becomes distinctly human, near the end of the first trimester? When the fetus becomes responsive to stimuli—again, at the end of the first trimester? When it becomes active enough to be felt as quickening, typically in the middle of the second trimester? When the lungs have reached a stage of development sufficient that the fetus might, just conceivably, be able to breathe on its own in the outside air?

  The trouble with these particular developmental milestones is not just that they’re arbitrary. More troubling is the fact that none of them involves uniquely human characteristics—apart from the superficial matter of facial appearance. All animals respond to stimuli and move of their own volition. Large numbers are able to breathe. But that doesn’t stop us from slaughtering them by the billions. Reflexes and motion and respiration are not what make us human.

  Other animals have advantages over us—in speed, strength, endurance, climbing or burrowing skills, camouflage, sight or smell or hearing, mastery of the air or water. Our one great advantage, the secret of our success, is thought—characteristically human thought. We are able to think things through, imagine events yet to occur, figure things out. That’s how we invented agriculture and civilization. Thought is our blessing and our curse, and it makes us who we are.

  Thinking occurs, of course, in the brain—principally in the top layers of the convoluted “gray matter” called the cerebral cortex. The roughly 100 billion neurons in the brain constitute the material basis of thought. The neurons are connected to each other, and their linkups play a major role in what we experience as thinking. But large-scale linking up of neurons doesn’t begin until the 24th to 27th week of pregnancy—the sixth month.

  By placing harmless electrodes on a subject’s head, scientists can measure the electrical activity produced by the network of neurons inside the skull. Different kinds of mental activity show different kinds of brain waves. But brain waves with regular patterns typical of adult human brains do not appear in the fetus until about the 30th week of pregnancy—near the beginning of the third trimester. Fetuses younger than this—however alive and active they may be—lack the necessary brain architecture. They cannot yet think.

  Acquiescing in the killing of any living creature, especially one that might later become a baby, is troublesome and painful. But we’ve rejected the extremes of “always” and “never,” and this puts us—like it or not—on the slippery slope. If we are forced to choose a developmental criterion, then this is where we draw the line: when the beginning of characteristically human thinking becomes barely possible.

  It is, in fact, a very conservative definition: Regular brain waves are rarely found in fetuses. More research would help. (Well-defined brain waves in fetal baboons and fetal sheep also begin only late in gestation.) If we wanted to make the criterion still more stringent, to allow for occasional precocious fetal brain development, we might draw the line at six months. This, it so happens, is where the Supreme Court drew it in 1973—although for completely different reasons.

  Its decision in the case of Roe v. Wade changed American law on abortion. It permits abortion at the request of the woman without restriction in the first trimester and, with some restrictions intended to protect her health, in the second trimester. It allows states to forbid abortion in the third trimester, except when there’s a serious threat to the life or health of the woman. In the 1989 Webster decision, the Supreme Court declined explicitly to overturn Roe v. Wade but in effect invited the 50 state legislatures to decide for themselves.

  What was the reasoning in Roe v. Wade? There was no legal weight given to what happens to the children once they are born, or to the family. Instead, a woman’s right to reproductive freedom is protected, the court ruled, by constitutional guarantees of privacy. But that right is not unqualified. The woman’s guarantee of privacy and the fetus’s right to life must be weighed—and when the court did the weighing, priority was given to privacy in the first trimester and to life in the third. The transition was decided not from any of the considerations we have been dealing with so far in this chapter—not when “ensoulment” occurs, not when the fetus takes on sufficient human characteristics to be protected by laws against murder. Instead, the criterion adopted was whether the fetus could live outside the mother. This is called “viability” and depends in part on the ability to breathe. The lungs are simply not developed, and the fetus cannot breathe—no matter how advanced an artificial lung it might be placed in—until about the 24th week, near the start of the sixth month. This is why Roe v. Wade permits the states to prohibit abortions in the last trimester. It’s a very pragmatic criterion.

  If the fetus at a certain stage of gestation would be viable outside the womb, the argument goes, then the right of the fetus to life overrides the right of the woman to privacy. But just what does “viable” mean? Even a full-term newborn is not viable without a great deal of care and love. There was a time before incubators, only a few decades ago, when babies in their seventh month were unlikely to be viable. Would aborting in the seventh month have been permissible then? After the invention of incubators, did aborting pregnancies in the seventh month suddenly become immoral? What happens if, in the future, a new technology develops so that an artificial womb can sustain a fetus even before the sixth month by delivering oxygen and nutrients through the blood—as the mother does through the placenta and into the fetal blood system? We grant that this technology is unlikely to be developed soon or become available to many. But if it were available, does it then become immoral to abort earlier than the sixth month, when previously it was moral? A morality that depends on, and changes with, technology is a fragile morality; for some, it is also an unacceptable morality.

  And why, exactly, should breathing (or kidney function, or the ability to resist disease) justify legal protection? If a fetus can be shown to think and feel but not be able to breathe, would it be all right to kill it? Do we value breathing more than thinking and feeling? Viability arguments cannot, it seems to us, coherently determine when abortions are permissible. Some other criterion is needed. Again, we offer for consideration the earliest onset of human thinking as that criterion.

  Since, on average, fetal thinking occurs even later than fetal lung development, we find Roe v. Wade to be a good and prudent decision addressing a complex and difficult issue. With prohibitions on abortion in the last trimester—except in cases of grave medical necessity—it strikes a fair balance between the conflicting claims of freedom and
life.

  When this article appeared in Parade it was accompanied by a box giving a 900 telephone number for the readers to express their views on the abortion issue. An astonishing 380,000 people called in. They were able to express the following four options: “Abortion after the instant of conception is murder,” “A woman has the right to choose abortion any time during pregnancy,” “Abortion should be permitted within the first three months of pregnancy,” and “Abortion should be permitted within the first six months of pregnancy.” Parade is published on Sunday, and by Monday, opinions were well divided among these four options. Then Mr. Pat Robertson, a Christian fundamentalist evangelist and 1992 Republican Presidential candidate, appeared Monday on his regularly scheduled daily television program, urged his followers to pull Parade “out of the garbage” and send back the clear message that killing a human zygote is murder. They did. The generally pro-choice attitude of most Americans—as repeatedly shown in demographically controlled opinion polls, and as had been reflected by the early 900 number results—was overwhelmed by political organization.

  * Cowritten with Ann Druyan and published first in Parade magazine as “The Question of Abortion: A Search for Answers,” April 22, 1990.

  * Two of the most energetic pro-lifers of all time were Hitler and Stalin—who immediately upon taking power criminalized previously legal abortions. Mussolini, Ceauşescu, and countless other nationalist dictators and tyrants have done likewise. Of course, this is not by itself a pro-choice argument, but it does alert us to the possibility that being against abortion may not always be part of a deep commitment to human life.