I'm treading into this discussion carefully because there have been a billion and a half discussions about this on the internet and they're all awful. But whatever. My view on this is probably a bit radical and it's kind of an uncomfortable thing to argue, but logically, it's the only one that makes any kind of sense to me. I'm going to start off with a couple of basic premises that shouldn't be very contentious.
First, destroying something that isn't human ("clump of cells") is permissible under any circumstance. On the other hand, we must agree that killing an innocent, defenseless person under any circumstance is wrong. All sides should be able to agree with me so far.
With that in mind, I think there is only point worth considering. All other things, be they horribly tragic like rape or incest (or in the case of the musician in a symphony, as in the philosophical argument), I think are irrelevant. The only point that matters is when, exactly, it goes from "clump of cells" to "human life." This is where it gets extremely dicey because we need to determine a precise moment in time, a singular second, before which, terminating the "thing" is completely permissible, and after which is the murder of an innocent human being.
If you believe in morality, or the existence or "right and wrong," that moment is extremely profound. Again, there must exist a point in time, when one second before, the act is completely morally permissible and one second after is a heinous moral act. There have been a ton of opinions on when that moment is, but there doesn't seem to be any consensus. This is why I don't understand the significance of rape or incest. I recognize that those situations are brutal and awful, but the origin of the human or non-human doesn't really matter. Either the product of rape or incest is human or it's not. Either abortion at a singular moment in the pregnancy is wrong, or it is not. How rape or incest figures into that, other than being extremely tragic, is beyond me.
At this point, I don't think I've offered any kind of opinion on the subject of whether or not abortion is right or wrong. I think this is how the argument should be framed.
Personally, I think it's impossible to determine at which point in time that is. I think the only thing that makes sense to me is conception. I understand the arguments against it, but haven't found any that were particularly compelling. I think my view is the safest bet. I mean, we're arguing in a very murky area about whether or not something is murder. Because here's the deal: either it's murder or it's not and I think it's best to err on the side of caution.
I think it's too gray and I think it's too risky and I think if people believe there are murders against human life being sanctioned by the state that it's a worthy cause for which to fight. I know I'm going to get shallacked on here for my opinion, but any other opinion I offered would be dishonest.