In this context, it might be useful to look again at language from Justice Blackmun's original Roe v. Wade opinion, 410 US 113 (1973). Today, what he had to say about the view of religion toward abortion is often forgotten:
The absence of a common-law crime for pre-quickening abortion appears to have developed from a confluence of earlier philosophical, theological, and civil and canon law concepts of when life begins. These disciplines variously approached the question in terms of the point at which the embryo or fetus became "formed" or recognizably human, or in terms of when a "person" came into being, that is, infused with a "soul" or "animated." A loose consensus evolved in early English law that these events occurred at some point between conception and live birth. This was "mediate animation." Although Christian theology and the canon law came to fix the point of animation at 40 days for a male and 80 days for a female, a view that persisted until the 19th century, there was otherwise little agreement about the precise time of formation or animation. There was agreement, however, that prior to this point the fetus was to be regarded as part of the mother, and its destruction, therefore, was not homicide. Due to continued uncertainty about the precise time when animation occurred, to the lack of any empirical basis for the 40-80-day view, and perhaps to Aquinas' definition of movement as one of the two first principles of life, Bracton focused upon quickening as the critical point. The significance of quickening was echoed by later common-law scholars and found its way into the received common law in this country. ...
Texas urges that, apart from the Fourteenth Amendment, life begins at conception and is present throughout pregnancy, and that, therefore, the State has a compelling interest in protecting that life from and after conception. We need not resolve the difficult question of when life begins. When those trained in the respective disciplines of medicine, philosophy, and theology are unable to arrive at any consensus, the judiciary, at this point in the development of man's knowledge, is not in a position to speculate as to the answer.
It should be sufficient to note briefly the wide divergence of thinking on this most sensitive and difficult question. There has always been strong support for the view that life does not begin until live birth. This was the belief of the Stoics. It appears to be the predominant, though not the unanimous, attitude of the Jewish faith. It may be taken to represent also the position of a large segment of the Protestant community, insofar as that can be ascertained.... As we have noted, the common law found greater significance in quickening. Physicians and their scientific colleagues have regarded that event with less interest and have tended to focus either upon conception, upon live birth, or upon the interim point at which the fetus becomes "viable," that is, potentially able to live outside the mother's womb, albeit with artificial aid.... The Aristotelian theory of "mediate animation," that held sway throughout the Middle Ages and the Renaissance in Europe, continued to be official Roman Catholic dogma until the 19th century, despite opposition to this "ensoulment" theory from those in the Church who would recognize the existence of life from the moment of conception. The latter is now, of course, the official belief of the Catholic Church. As one brief amicus discloses, this is a view strongly held by many non-Catholics as well, and by many physicians. Substantial problems for precise definition of this view are posed, however, by new embryological data that purport to indicate that conception is a "process" over time, rather than an event, and by new medical techniques such as menstrual extraction, the "morning-after" pill, implantation of embryos, artificial insemination, and even artificial wombs.
