Wow, thank you for taking the time to write all of that in response to what I wrote. There isn't any way right now that I could reply to it all, but I'd offer a few thoughts.
You rightly point out that viability is a biological/physiological fact. The "fetus" or "embryo" up to a certain stage is unable to live on its own. It depends upon the mother for its nutrition and survival, as well as its development. Granted.
Now as to what you say, philosophically it has problems. It can't be true that the only difference between the cells that form the human fetus and those of other organisms, such as other species of animals, is simply the "location" as you said. If I took some of the animal cells out of their location and implanted in place of the fetus, would a human being grow? No, of course not. Thus there must be some difference in the cells themselves which differentiates them from those of other species of animals or even other cells within the same "host" organism (mother). You could take cells, let's say, from the mother's heart and implant them in place of the developing fetus and, again, you'd have no developing child. The fetus instead is a complete organism that has its own genetic blueprint that contains the details of its development all the way through to adulthood. Any eighth grade biology student would be able to show that it exhibits the characteristics of life. It is therefore a living thing, in the genus animal, and all animals must belong to some species. You can't just say it's an "animal", since nothing exists that is "just an animal", nor could anything exist that is generically an animal. It has to be some kind of animal. What kind is it? If it's not human, what species would you put it into?
How is it that "viability" is as essential part of your definition of a "person"? What basis do you have for defining it this way? You claim that science does this. Since when does modern science claim to make a philosophical definition about "personhood" and what is involved in being a "person." I would define a "person" as a "substance of a rational nature." How would you define it? The unborn child has a rational nature. Here I'm using "nature" and "species" to mean the same thing. An unborn child, as I pointed out, can only reasonably be classified in the species "human." It has a rational nature, but in the fetus this nature is in potency, much like we say that man is "rational" in his nature, but have you ever seen a baby (after birth) that could reason? No, because that ability is there only in potential. Obviously you would say that the baby is a "person." I'd be interested to see how you are defining "person."
Responses to particular points:
1) You wrote (concerning the quote from Scripture about God knowing the child before he "forms" it in the womb): "It implies nothing at all about the fetus being a person or "life" beginning at conception. It merely means that God had intentions of, and therefore knowledge of, bringing a given person into existence. It has absolutely nothing at all to do with a fetus being a person, which it isn't."
I would respond that it, from a theological perspective, on principles that should be acceptable to any Christian (who must accept the authority of Scripture), establishes several things: first, it establishes the love of God for the being in the womb, which is expressed by his "knowing" of it. Second, it establishes that it is His work, because He is the One Who formed the child. Third, it goes toward establishing the personhood of the unborn child, since God is speaking of the unborn child as the same as the one reading the Scripture..."before I formed you in the womb." Thus the one formed in the womb in the beginning is the same as the reader, who is obviously a human person. Now of course, this argument, since it comes from Scripture, is only meant to serve as an argument for the Christian, since non-Christians cannot be expected to accept such an argument on the basis of an authority that they do not accept.
2) You wrote: If this is an argument for your rationale of a political position, it is invalid. The United States is a secular nation, and "Congress shall make no law in respect to a particular religion." (Source: The Constitution)
With all due respect, I urge you to read the founders and the Constitution more closely. First, the Constitution does not protect the country from religion. Rather, it protects religion from government coercion and interference. It does not follow that because the government may not establish a religion that religious arguments are not "valid." Many of the founders, from Jefferson to Madison to Franklin and Washington, made arguments from Scripture with regards to the new Republic. They certainly were not, for the most part, unreasonable enough to make the outrageous recent claim that the citizens of a predominantly Christian nation should ignore the teachings of Scripture, as if they were one being on a political level and another on a religious level.
3) You wrote: "You go on to say, "If it is a child, created in the image and likeness of God, what right does society have to sanction its death? None, of course-none whatsoever." I would hope you don't support capital punishment. Someone who has committed crimes and evil acts are still made in the image of God. Human judgements are fallible and often wrong, and we don't have the moral authority to murder someone."
It does NOT follow that because life is sacred, and because innocent life ought never to be taken under the sanction of the state, that those who are guilty of grave offenses should therefore not have their lives taken at the sanction of the state. To equate innocent, unborn children with convicted murderers is erroneous. If this principle did not admit of exceptions, how could one defend themselves in the event of a life-threatening attack upon his family? The same would hold for the case of wars. Wars almost inevitably lead to loss of life, and even sometimes innocent life. So how is it that a war could be justly engaged in? Clearly, in defense, an attacker may be repelled, whether on an individual or state level, by appropriate and even deadly force. The primary intention is to stop the attack and not to kill people. In the case of the man guilty of murder, there is a penalty of justice that is due, as well as an interest in protecting society from further crimes. The penalty is so severe and irrevocable though that it ought to be used as a last resort and only with clear and compelling evidence.
You wrote: "I must add that abortion is far from murder, assuming the abortion takes place before the fetus is viable. I do admit, late term abortions are a sad reality. It is scientifically accepted that when a fetus is viable, it gains consciousness in the brain, and is therefore human. Abortions after this point would certainly constitute murder, and I frown deeply upon that."
This assumes that viability is essential to classification in the species human, as I pointed out above. I haven't seen any defense of this assumption. You simply have stated it. If I hook a man to a respirator and/or a feeding tube, and he's unable to live on his own, but he depends upon the respirator and/or feeding tube, does he cease to be a human person? Would it be morally licit to walk in and chop his head off or scorch him? How does the lack of "viability" determine the existence of a human person? If this were so, with the changing technology that man has available, the definition of human person would change. So the same child in the womb, at the same stage of its development, could be a human person today and not tomorrow. Does that make any sense to you as how to define personhood?
I really don't want to go into the issue of homosexuality. I brought up that issue only as regards marriage. I don't make any assertion about the genetic influence on homosexuality, and it's quite possible that there is a genetic link, although that hasn't been conclusively shown. That in no way affects whether marriage should be between two people of the same sex. Again, it's all about definition. What is marriage? Men have defined it as an institution centered around having children and the nurturing of the family. Even in societies where homosexuality was well accepted, marriage was never previously redefined accordingly. Of course someone can love someone else of the same sex. But is love all that is required for marriage? I would reject that claim. Marriage is an institution based upon family, not just love. Often, it's the children who hold a marriage together even after the love has passed.
You wrote: "The Constitution forbids banning same-sex marriage. The Constitution guarantees equal treatment and equal opportunity under the law, regardless or race, sex, religion, upbringing, or sexuality. We do not have the right to refuse others their right to happiness, especially when it's within the boundaries of the law."
The Constitution does NOTHING of the sort. I again urge you to read the debates on the ratification of the document and all of the founders. These matters are left to the states, if they are to be political issues at all. They are not at all under the purview of the federal government. Matters that are so close to the lives of so many people as the institution of marriage were never considered federal issues since the powers delegated to the Constitution, as the Federalist points out, "are few and defined." The powers of the states are "broad and indefinite." Such an understanding of the Constitution turns our federal system on its head. Marriage, family issues, internal things of that matter are state matters. The federal government has no authority whatsoever to dictate to the states how to handle it.
You wrote: "I agree with you that people are too caught on to party leadership. But simply because someone supports abortion or same-sex marriage does not mean they do not know right from wrong; rather, they understand it even better. Ethically speaking, everyone should be treated and loved the same regardless of their sexuality. Ethically speaking, a woman should not be forced to go through child bearing/birth. Ethically speaking, a child should not have to be brought into the world if it is unwanted."
My friend, I agree 100% with that. It is wrong to hate people because of their "sexuality" as you say it. It is even wrong not to love them. Ethically speaking, a woman should not HAVE to be forced to go through with child bearing. She should welcome it as a great gift and blessing and a fulfillment of her femininity. Ethically speaking, a child should not HAVE to be brought into the world unwanted. He should be welcomed with open arms, as a gift of God. It doesn't follow from this that the law, the peoples' guide, can allow that child to be killed before birth. No, it follows from this that we have a duty to WANT these children, these little gifts of God, or if you don't believe in God, these little "gifts of nature." Whatever you want to say. It is unethical for a woman to be given such a gift and not want it. It is unethical to have sex and not be willing to take responsibility for that should it mean the transmission of life.
I don't agree that pro-life people "couldn't care less about the well being of the child once it's here." That's a horrible accusation. It is ad hominem and beneath the effort you showed in the rest of your post. Adopted children are 43% more likely to commit suicide or be victims of depression? And therefore, by implication, we should kill them before they are born? I do not see it. No, if we had a society of love, where they are welcomed as gifts and blessings, we would not have that problem. It's the society that produces abortion that produces this depression and suicide as well.
Again, thank you for your post, and I hope that my response will be taken in the spirit in which I intend it, with the utmost respect, but with a sharp disagreement.