The Mosaic Law has not been superseded, but the law of Christ has been superimposed on it.
See what I mean? You gave me a long, rambling, weird answer, starting off with A = !A. If you have two sets of laws, Law Group A and Law Group B, and Law Group B is superimposed on Law Group A, then you're following Law Group B, and you're not following Law Group A.
Therefore, Law Group A is superseded. How in the world can a new set of laws be enacted without superseding the old group?
It doesn't nearly need to be so complex, and the only reason why you feel compelled to make this more complex is because you're trying to have your cake and eat it, too. You're trying to say, "The old law is still valid, but we don't have to follow it". If you don't have to follow a law, then it's not valid. A law is either valid or not. There is no middle ground, but that's where this nebulous, irrational "fulfilled" business comes in.
> So what are we to do with all of these laws? We have to approach them as revelation of God (which they still are), not as rules for society (which they once were) or means of salvation (which they never were).
Do you have to follow them or not? You don't have to follow them. Therefore, they are nullified. Thrown in the trash.
> Paul said we are no longer under the supervision of the law (Gal. 3.25) since it has been superseded (Ga. 4.1-7). But in Romans 3.31, Paul specifically says, "Do we, then, nullify the law by this faith? Not at all! Rather, we uphold the law."
I know what the "apostle" Paul said, and he thought he was important enough to nullify God's law by saying we weren't under it. It's irrelevant. And then he spoke out of the other side of his mouth and said that we "uphold" it. But what does that mean? If you don't have to follow it, and you're not under it, and it has nothing to do with your salvation, then "upholding" it is a worthless, futile gesture. Paul was clear that he though the law was garbage:
"What is more, I consider everything a loss because of the surpassing worth of knowing Christ Jesus my Lord, for whose sake I have lost all things. I consider them garbage, that I may gain Christ and be found in him, not having a righteousness of my own that comes from the law, but that which is through faith in Christ—the righteousness that comes from God on the basis of faith." Phil 3:8-9