John T. Noonan makes the argument that the jump in probability for a fetus coming to term, at a specific point in the development of the fetus, has an important implication for the humanity (personhood) of the fetus. He bases this argument on the reasoning that life itself is a matter of probabilities, and most moral reasoning is an estimate of probabilities. He goes on to state that his argument in which a fetus has an implication for the humanity of the fetus is strictly an appeal to probabilities that actually exist. To demonstrate his point concerning probabilities he uses an analogy. The analogy he uses is of a man who shoots into the bushes because of movement in the bushes. If the chances of this movement in the bushes being a man were 200 million to one, then no one would think anything of him firing away into the bushes. However, if the chances are 4 out of 5 that the movement is a man, then you would not be justified in firing into the bushes. He uses this analogy to relate it to the development of a baby. When a male ejaculates he emits about 200 million spermatozoa. Of these 200 million, only one single spermatozoon has a chance to develop into a zygote. Noonan says that therefore, if one spermatozoon is destroyed than youre only destroying a being that had a one in 200 million chance of ever developing into a reasoning being. This would be similar to the case of shooting into the bushes when there is a one in 200 million chance that the movement is that of a man. On the other hand, if a fetus is destroyed, then youre terminating a being that had an 80 percent chance of developing further into a baby outside the womb who, in time, would reason. This would be similar to shooting into the bushes when the movement has a 4 out of 5 chance of being that of a man. The probability of the baby becoming a full being of reason drastically changes from a single spermatozoon (1 in 200 million) to a fetus (4 out of 5). This probability change is important because it leads you to believe that aborting a fetus is wrong because of the high probability it has of becoming a being of reason.
Judith Jarvis Thomson offers a rather interesting analogy to an unwanted pregnancy. Thomson begins her analogy with the hypothetical situation of waking up and finding oneself wired by their circulatory system to a stranger. The stranger turns out to be a famous violinist and the Society of Music Lovers kidnapped you because you were the only hope for the violinists survival. In order for the violinist to be saved, you must remain wired to that person for 9 months. The key point to this analogy is that you were kidnapped and did not have a choice to be wired to the violinist or not. You were forced into it. Analogously, when a female is raped and impregnated, they did not have a choice; they were forced into it. The analogy works well in rape cases, but not in all unwanted pregnancy cases.
A rape is very similar to this hypothetical situation because a rape is forced upon you without your choosing. Similarly, in the hypothetical situation the person did not choose to be wired to the violinist; she was kidnapped and forced to by the Society of Music Lovers. This analogy would not work well, though, with a case in which a female voluntarily has sex and gets pregnant without intending to. The pregnancy was unwanted, but she chose to have sex; she was not forced into it like the case of the person and the violinist. The analogy therefore, does not work well with all unwanted pregnancy cases. Regardless of whether the analogy is reasonable or not, the quality of this comparison is irrelevant for her larger argument.
Thomson makes her large argument real clear by explaining her position clearly, thoroughly, and through the use of analogies. The larger argument she makes is that the mother has certain undeniable rights such as the right to control her own body. And these rights can at times outweigh the right to life of a fetus in cases of rape, of threat to her life, or when she has tried very hard and responsibly not to get pregnant. Thomson goes on to say, however, that womens rights do not justify all cases of abortion such as those for mere convenience purposes. Although Thomsons analogy of the violinist may seem a bit shaky, it doesnt really have an effect on the way she makes her points concerning her stances on abortion. She clearly addresses many radical and traditional beliefs of abortion throughout her essay, and then she refutes many of them through means that are unrelated to the initial violinist analogy. Therefore, the quality of the violinist analogy doesnt really affect her overall argument and position on the issue.
I personally tend to agree with Thomsons views concerning abortion. I personally believe that it is absolutely justifiable to have an abortion in cases of rape, of threat to the mothers life, or when she has taken reasonable precautions not to get pregnant. I also believe that a mother should not be able to abort a fetus just because she feels the child would be an inconvenience. I feel very passionate that it is absolutely morally permissible to have an abortion in the case of a rape. In cases of rape, sexual intercourse and ultimately pregnancy, was forced upon a female without their choice. To tell a woman that she must then go through with this pregnancy in which the father is some heinous creep would just be plain wrong. Not to mention that she didnt want this pregnancy in the first place. I also believe that a mothers right to life is just as important as a fetuss right to life. Therefore, if going through with a pregnancy would be life threatening then a mother should have the right to abort the fetus. If a mother would choose to die in order for the baby to be born then it would be an incredible superrogative good, but she is under no obligation to sacrifice herself on behalf of the fetus. If a person has taken a responsible and reasonable precaution not to get pregnant, but does, then I feel they should also have the right to abort the fetus. I just think that as long as a conscious effort was made to prevent pregnancy, then it is morally permissible to have an abortion. Abortion would not be morally permissible, in my opinion, for cases in which it is done for the sake of convenience. I strongly believe that a fetuss right to life outweighs any convenience issues in which the parents might have.