Atheism is simply stated not believing in the existence of a God or gods. Any characterizations of atheism or of atheists that may be made beyond this point are not essential to the atheist platform. Yet, many often attribute a number of other ideologies or paradigms to atheism. For example, it is generally assumed that atheism has an inherent bias toward non-capitalistic economic systems. This is not true as demonstrated by the disagreement between Philosobot who leans more in favor of free-market capitalism and me who leans somewhat away from the same. In a similar vein Shermer (2006) defends capitalism as a healthy fitness-inducing economic system based on his application of evolutionary mechanics to economics. There are hence atheist representatives on many points of the political, economic, and moral spectrum. The issue of abortion is no different.
Though it might be immediately assumed that all atheists are in favor of pro-choice, abortion rights to women, this is not the case. As Philosobot and I are sometimes on different ends of the spectrum in our views, we disagree on the the matter of pro-choice or pro-life morality. We disagree on this issue and discuss it from time to time. Despite our polarity on this issue, we do agree that the issue is rather gray. The biblical theist might argue that our lack of a moral compass such as the Bible is the reason for the grayness that we perceive on this matter. To this I respond that the Bible is ironically quite gray on the matter of the moral or legal status of abortion.
Search from cover to cover in the Bible and there will not be found a clear and explicit imperative against abortion. Be she a Catholic, a Protestant, a Muslim, etc. the theist today considers the abortion of a fetus to be the killing or the murder of an unborn person. However, despite the numerable case laws against specific murder situations (e.g., self protection in the dark, self protection in the light, accidental murder, deliberate murder, the finding of a slain person without an accused, the killing of a person by your ox, etc.), never is the issue of abortion addressed. For how outspoken the Christian community is against abortion, the Bible is oddly silent on this matter.
There is, however, one passage in the book of Exodus that touches on ethical priorities related to the modern moral dilemma of abortion. The passage is as follows:
And if men strive together, and hurt a woman with child, so that her fruit depart, and yet no harm follow, he shall be surely fined, according as the woman's husband shall lay upon him; and he shall pay as the judges determine. But if any harm follow, then thou shalt give life for life, eye for eye, tooth for tooth, hand for hand, foot for foot, burning for burning, wound for wound, stripe for stripe (Exodus 21:22-25).
The above passage is the only legal case that touches on the legal-ethical status of the unborn in the Pentateuch. Other passages touch on the ceremonial status of the new born--conferring an innately more impure status to the female infant over the male (see Leviticus 12); yet, none but this pericope contain legal-ethical material about the status of the unborn. Note, this passage is unclear. It is not clear as to whether or not the "...yet no harm follow," relates to the mother or to the infant, and a case can be made for both. In fact, the Jews, the masters of Pentateuchal jurisprudence, disagree on this matter.
The nearly uniform voice in Rabbinic interpretation of this passage asserts that the mother is the sole subject of harm. There is no consideration given for the unborn fetus--dead or alive. Philo and a number of Medieval Karaite Jewish interpreters favor the position that the injured party is the premature child. Both schools of interpretation raise significant textual arguments in favor of their positions; however, the text is markedly unclear over the identity of the injured party.
For the amount of attention and contempt that American Christians exhibit toward abortion or the pro-choice platform, it is ironic that the only passage in the Bible possibly touching on the ethical-legal status of the unborn relates to an obscure case law with conditions that frankly do not apply today. We no longer, for example, apply the Lex Talionis of "eye for eye and tooth for tooth" nor can we apply it in the context of modern punitive systems that rely less and less on corporeal punishment.
There are several significant moral issues that Christians adhere to strongly today that have mere hairs of biblical support. There is obvious biblical room for disagreement on the matter of abortion due to the silence of the Bible on the same. This again is an example of where the theist is really left "to lean on his own understanding" because the Bible is a poor and irrelevant ethical workbook. The Bible Christian theist with her Bible must use her own instinct, conditioning, and reasoning to forge her ethical conclusions on the issue of abortion. Maybe she will finally recognize how gray this issue is so that she will stop trying to use the arm of political clout to legislate black-and-white morality into the world of gray.