But in addition to those who thought that the individual soul existed before conception, there have been those who thought that the individual body existed before conception, in the shape of the father's semen. Onan, in Genesis, spilt his seed on the ground; in Jewish tradition this was seen not only as a form of sexual pollution, but an offence against life. Aquinas, in the Summa Contra Gentiles, in a chapter on "the disordered emission of semen" treats both masturbation and contraception as a crime against humanity, second only to homicide. Such a view is natural in the context of a biological belief that only the male gamete provides the active element in conception, so that the sperm is an early stage of the very same individual as eventually comes to birth. Masturbation is then the same kind of thing, on a minor scale, as the exposure of an infant. The high point of this line of thinking was Pope Sixtus V's 1588 bull Effraenatam, which imposed an excommunication, revocable only by the pope himself, on all forms of contraception as well as on abortion. But the view that masturbation is a poor man's homicide cannot survive the knowledge that both male and female gametes contribute equally to the genetic constitution of the offspring.
At the other extreme are those who maintain that it is not until some time after birth that human rights arise. In pagan antiquity, infanticide was very broadly accepted. Jones quotes a chilling letter from a husband in Alexandria to his wife in first-century Rome. "If you are delivered of a child before I come home, if it is a boy, keep it, if a girl discard it." No sharp line was drawn between infanticide and abortion, and as a method of population control abortion was sometimes regarded as inferior to infanticide, since it did not distinguish between health and unhealthy offspring.
In our own time, a number of secular philosophers have been prepared to defend infanticide of severely deformed and disabled children. They have based their position on a theory of personality that goes back to John Locke. Only persons have rights, and not every human being is a person: only one who, as Locke puts it, "has reason and reflection, and considers itself as itself, the same thinking thing, in different times and different places". Very young infants clearly do not possess this degree of self- awareness, and hence, it is argued, they are not persons and do not have an inviolable right to life. Since such a thesis is far removed from any of the Jewish or Christian traditions recorded in his book, Jones does not spend much time discussing it. Rather, he takes the rejection of infanticide as a starting point for the evaluation of the other positions that he does take seriously. Any argument that is used to justify abortion or IVF or stem cell research must undergo the following test: would the same argument justify infanticide? If so, then it must be rejected.
The central issue, then, is to record, and decide between, the three alternatives from which we began: should we take individual human life as beginning at conception, at birth, or at some point in between? If the correct alternative is the third one, then we must ask further questions. When, in the course of pregnancy, is the crucial moment? Is it the point of formation (when the foetus has acquired distinct organs), or is it the point of quickening (when the movements of the foetus are perceptible to the mother)? Can we identify the moment by specifying a number of days from the beginning of pregnancy?
Some familiar texts from the Bible suggest that we should opt for conception as the beginning of the individual life of the person. "In sin did my mother conceive me" sang the Psalmist (51: 5). Job cursed not only the day on which he was born, but also "the night that said 'there is a man-child conceived'" (3:
3). That individual human life begins at conception is a view found in some rabbinic texts, and in the early Christian Church it was held by Tertullian in the West and Gregory of Nyssa in the East. Since 1869 it has been the dominant position among Roman Catholics, but for most of the history of the Catholic Church it was a minority view. As Jones shows clearly, the theologian who first brought it back into favour among Western Christians was Martin Luther.
It has been much less common to regard personality and human rights as beginning only at the moment of birth. But one important rabbinic text allows abortion up to, but not including, the time when a child's head has emerged from the womb.
Some Stoics seem to have taught that the human soul was received when a baby drew its first breath, just as it departs when a person draws his or her last breath.
Through most of the history of Western Europe, however, the majority opinion has been that individual human life begins at some time after conception and before birth. In the terminology that for centuries seemed most natural, the "ensoulment" of the individual could be dated at a certain period after the intercourse that produced the offspring. Among theologians and canonists in the West "there was a consensus", Jones tells us, "that the human soul was directly created by God and that it was infused into the embryo when the form of the body was complete, generally held to be 40 days or thereabouts".
