In the spectrum of thought, we have objectivity and subjectivity. Objectives are static and unchangeable, and one of the main objective items we know of is fact.
Subjectivity, on the other hand, can change because you think it's a certain way. Included in this are morals and beliefs.
Science is an objective subjective. It is subjective but said subjectivity must be proved with objective fact.
Now, for abortion. Pro-life bases the main body of their argument on morals. This is making a subjectivity objective, which is an impossibility.
For example: "Abortion is murder because I think it is. "This is a fairly common argument, and the main fallacy is the objectivity. This is an amazing example of subjecting an objective. Murder, in this case, is the objective fact, in that it is legally defined and for something to be murder, it must fulfill a set of requirements. Since abortion is a debate on legality, murder must be objective according to the law. Since the main debate is in the Western-based countries(Canada, the US and the UK), then this definition must be objective to the laws of these countries. Therefore, unless something fits the requirements of murder, it is not murder.
Pro-choice, on the other hand, believes in the subjective. Since morals are subjective and cannot be made objective, the best thing to do is allow the subjectivity, ergo, give the choice of havign an abortion to the person or people it involves - the pregnant woman.
Now, a possible fallacy is that "the fetus has no choice in the matter," but personhood is also objective. It is legally granted at personhood, and like murder, it cannot be made subjective. Since the fetus has not been born, it is not a legal person, and therefore the woman's say overrides the fetus' say.
Now, the law is also objective-subjective. It can be changed, depending on the influence of the person creating the amendment. However, if you do change it - in this case granting the fetus personhood - then the change will affect certain other things. In this case, granting the fetus personhood will do nothing, as no person may use another person's vital resources to live without first having the donor's consent. Therefore, nothing changes as the woman's right to bodily autonomy overrides the fetus' right to a life.
Another common pro-life argument is "They shouldn't have had sex if they didn't want a child." This is a restriction of freedoms, as people have the right to do what they want privately, within the already existing laws. As of May 25, 2006, there is no such law prohibiting sex between two consenting people at or above the age of consent without intent to produce a baby in Canada, the United States, or the United Kingdom. Thus, saying they should not have had sex is a restriction of private freedom.
That is all for this argument, and I do hope you have read it thoroughly.
http://www.gaiaonline.com/journal/?mode=view&p=3704497
