Hopefully this will remain a cordial discussion :D

It seems that many pro-choice advocates are not in favor of abortions per se, but of women's rights in terms of their right to decide what happens to, and I've heard this term used often before, their own bodies. On the other hand, there are those who take philosophical issue on the dehumanizing of what they consider to be fully human, and thereby murder or not.
Of course there are asshats who simply don't consider other peoples' perspectives, but I will just omit those kinds of views from discussion, as I don't think that they are conducive to anything.

Before I begin I would like to make the argument that, in my mind, the resolution of such a decision lies in whether or not humanness is a binary with all humans having an equal right to life, and if so, whether, or when, humans become "unkillable". That is, if I am certain that fetuses have the same humanness as I feel I do, then I would make the claim that abortion is in fact murder, and morally wrong. On the other hand, if I were to become convinced fetuses are in fact either subhuman, or completely unhuman, then abortions should be morally equivalent to killing a mosquito.

Now, I am leaving the fact that only women are prone to pregnancy entirely out of this issue. It is extremely unfortunate that it might be moral to place life-altering restrictions on a group that is already considered to be treated at a substandard level (as compared to men) by a variety of institutions. However, if it were only men that might get undesirably pregnant, my stand would hold identically. I fundamentally do not think that it is a question of women; it is a question of what is murder?

Of course there are societally pragmatic definitions for morals as those things which can bring about positive effects upon the whole of society. For example, murder is deigned inappropriate because it is harmful to society as a whole. Under this perspective, freedom of abortion is an obvious conclusion; a world in which babies that would otherwise grow up in environments where it is most often difficult to raise them, added on to the emotional baggage of the parents and the restrictions upon their own strivings, plus an understanding that a low population is no way a struggle of this century, means that abortions make society better (barring the effect of accepting it on peoples' psyches and beliefs regarding what things we are allowed to kill).

At the same time, such a definition for morality, especially the morality of murder seems fairly misaligned with reality. For example, we do not have massive campaigns to rid ourselves of people with very heavy mental disabilities, even though this would also be societally favorable–it would mean that their genes are more certainly not passed down and it would allow for, again, a better situation of those who would otherwise have to care for them. Nonetheless, such an initiative would be almost unquestionably cruel and immoral. It would near-genocidal and it would unquestioningly be considered murder.

It seems, therefore, that there is some fundamental nature in humans that we value, and we thinks makes them "unkillable". It is far more cruel to, most people would say, commit genocide than to hire an exterminator, even though the latter is likely killing a much larger number of individuals. Further, as much as we may deny it, it seems that many humans have a disposition to value some lives more than others. For example, when someone commits an atrocity awful enough, there is a sizable percentage of people that believe it qualifies them for being killable. More interestingly, a common response to the question "what would You do if You have a time machine?" is going back and assassinating figures who caused many deaths, such as Hitler or Stalin. And the only moral qualm with such an action is typically associated with the butterfly effect and not the moral question of whether murder to save lives is acceptable. Therefore, it seems that almost everyone thinks that many lives are worth more than one. It seems like a very basic conclusion to arrive at after all this text, but we're starting to progress.

At another point in time, I have heard in response to the debate that it is in part an issue of deciding something where it is clear that something has at some point in time occurred, but that it is difficult to specify when. This kind of issue is apparent, for example, in all kinds of government age-limits. For example, it is recognized that 15 is probably much to young to be drinking alcohol, or being an adult and by 25 most people should be allowed to do so. Nonetheless, the exact age is a somewhat arbitrary decision between those points in time. Likewise it seems that perhaps (if we are assuming a binary human-not-human descriptor) humanity is something that occurs after sexual intercourse, but before the age of 3 years (by which point a vast majority of toddlers exhibit consciousness). Nonetheless, it seems that this binary is not reflected by policy and many opinions. The fact that abortion is widely accepted, to begin with, is a demonstration that killing a fetus does not equivalate murder. Likewise, a quick Google search informed me that the maximum sentence for manslaughter is 25 years, whereas for infanticide it is 5 years. A plausible definition for murder might include the removal of consciousness of intelligence. But then taking drugs or getting a concussion are minor murders, a lobotomy is death, and killing someone who is braindead is an entirely insignificant action. In any case, such a definition, would imply, that the mentally disabled are less deserving of life and that mentally highly functioning individuals are more deserving. Further if such is the case, there should be no difference between infanticide on newborns and an abortion a couple of weeks later. In such a case, we could define a neural scale for how alive someone is and how much we kill it but completely stopping it's brain activity. Such a definition is repulsive.

This brings another point and another degree of consideration. The contrast between repulsiveness of actions and pain. A fetus before a certain age has little nervous system so if harm is defined in pain this should be fair game. This is especially considering that the abortion would alleviate the parents considerable pain. This approach is not unlike vegetarians who are willing to eat animals that were raised and killed in ways that did not bring them pain. On the other hand, there is something fundamentally repulsive, in my mind, in the thought of killing, anything from a fetus to a mosquito. Then again, I also think cheese is repulsive. But it seems that killing is generally a repulsive act. Movies depict (and I have no way of knowing how mythical this is, but it seems to make sense to me) people getting light-headed and vomiting on the sight of corpses (especially if they're recently, and gruesomely disease). Images of dismembered fetuses and such that pro-life activists like using, have a similar emotional effect. I think it's a tricky question.

I ask myself, therefore, on what philosophical basis the liberal movement so immediately supports abortion. To my understanding, the entire social philosophy of liberal movements is supporting otherwise disenfranchised and powerless groups. I understand, of course, entirely how abortion helps bring women power. But at the same, this seems to overlook the point that it removes from fetuses (which really have no testimonies or internal spokespeople) an even greater degree of rights. So I ask, how can so many people look at the question of abortion without looking at the question of murder?