I'm genuinely not trying to have a go and engage in argument for argument's sake. This is a very relevant issue to me and, as of now, I remain unconvinced that my position is the Christian one.
Putting matter in such a simple statement allows me to answer in a uncomplicated manner. I an not simply "unconvinced", I am certain that my position is not a Christian one. However, I do not live in a Christian world.
In addition, while I do not consider "natural law" to be over the Law of God, to some extent I believe they are compatible. After all, it was God who created nature. Self preservation is a strong drive in EVERY living organism. As is reproduction. Freud once was attributed to saying that you can boil most human drives down to two main things: sex and death. I do not agree with Freud on all matter (or even most), however, he may have a point here. Self preservation and the desire to reproduce are two of the strongest drives in any living thing. It has been stated on this thread that many of my views on self defense are a justification rather than actually the teachings of Christ. That is not wholly incorrect. They are a justification, based on my way of seeing the order of things. Like with sex, the desire to reproduce is strong, so in my view celibacy is NOT a natural state for man. I read all scripture regarding sex in this context. To me, the Scriptures do not forbid sex, they give limits to where and how it should occur. I see killing in self defense in the same manner. Given the strong drive toward self preservation, passiveness is NOT natural. I read the scripture in this context. This leads me to derive the following from reading scripture:
1. Life is precious, and every attempt should be made to preserve it.
2. We should live our lives with forgiveness being the default point of view, not vengeance.
3. God did not bring death into the world, man did. Killing is never a sinless act since killing is NOT perfection.
4. We should not kill out of passion or covetousness. We should not kill in anger.
5. If a situation can be handled with non-lethal means, it should be. Taking another person's life is not a trivial matter. In doing so, you remove any chance of that person's repentance. What is worse, you are taking his life at a time that he is probably committing a sin, and he will not have a chance to repent of that sin if lethal force is used. As such, if you can survive the assault, you would do best to "turn the other cheek".
6. In a case where it is apparent that another person means to take my life or the life of one that I have a duty to protect, it is permitted for me to use the means at my disposal to prevent him from doing so. If this results in his death, so be it. I will have sinned, and the canons prescribe a penalty for that sin. However, unlike the attacker, I will have time to repent.
7. My beliefs above also lead me to be against aggression. My actions should be strictly defensive, and I should strive to do nothing that would bring aggression upon me.
I believe that a complete reading of the Scriptures, the Canons, and the writings of the Fathers - as well as the civil laws of our society, would show my views above to be compatible with Christianity in a non-perfect world. My views, however, are NOT perfection and are fallen along with the rest of me.