Thanks for the invite to answer another question! Your assertion this time that fundamental principles can be used in application to the problem of right and wrong can be said to be correct in part. There is also the iteration, the test of one solution against challenges that draw the first conclusion into doubt. I guess, in the judicial arena, this would be the appeals process, whether it be something like appealing a death penalty conviction or appealing a decision based on a law that is called into question by new evidence or a philosophical challenge. The physical properties of the universe cannot be said to be enough to draw upon fully, as they do not, as yet, take into account cognition and intelligent response. I don't think that there will always be a "case closed" conclusion to judicial decisions; just look at Roe vs. Wade. The tide of political thought turning toward the religious right calls this decision into many agendas again even long after the decision has been handed down.
In practice, "right" and "wrong" appear to correlate to a societal stability curve; society will allow just so much challenge on just so many levels and then it will react and the standards will change. There are many fundamental standards, most prominently the Ten Commandments. Although they are worded for the ancients, they address those behaviors that must not be allowed for the good of the group. Killing is not only wrong, but it is disruptive. But take that idea into war. Martin Sheen's character Willard in "Apocalypse Now" said it best: "Charging a man with murder in this place was like handing out speeding tickets at the Indy 500." It is still wrong and disruptive, but the environment has changed to make it necessary-i.e., it is a war zone. So right and wrong can be defined under controlled circumstances, but in the enforcement of these laws must be tempered by many factors (in a courtroom setting they might call these "mitigating circumstances." ) Some of these circumstances are enough to forgive the wrong; some are insufficient. But the system is so complex that they are almost never exactly the same (but they often follow patterns that can become blinding to those too accustomed to dealing with them over and over). Thus the occasional case of overreaction--police brutality where the offense does not match the treatment meted out, deadly force used against a man who holds a fake gun, etc. etc.,; judgement by humans and on humans is vastly imperfect. The creator of a law might not be able to see the effects that law might have 200 years down the road. Take the continual back-and-forth arguments over the Second Amendment to the Constitution of the US. Part of its original purpose was to enable citizens to protect themselves from the government, not just from random threats. The right to bear arms shall not be "infringed." It has been constantly infringed since it was written, mainly in response to abuses of the right. However, this has the effect of defining as "wrong" those people who feel the need to carry guns to protect themselves in New York City, when such a practice is illegal there. Thus, a right is made into a wrong by legislated reaction to abuses. The 4th Amendment protecting against "unreasonable search and seizure" can be abrogated by the government by the Patriot Act in reaction to another abuse--terrorism. Thus rights become wrong and the tide turns to the ones in power decreeing what is right and what is wrong. So, we come full circle and I find myself agreeing with your assumption that universal principles could be used to explain this, as it comes down to exercise of power in the end; however, other trends exist, and I seem to have gotten off on a tangent.
I am not arguing for moral relativism as a "right" thing; however, I am pointing out that this relativism DOES exist and is driven by forces other than philosophical or ethical ideals. Thus, in practical everyday application of morality to life, we must take into account the ones who do not see "right" and "wrong" as we do, or who see it but choose to ignore it in order to exercise force to gain an end.
OK, that's a lot of long-winded answers on my part! I am waaay past my bedtime! It's been fun!
P.P.S. I read your addendum, eros_halo, and I wonder how you can end it with a blanket assumption that the Bible is the inspired word of God without citing some sort of test to determine this. If this is so, then would not the other holy books of other religions also be inspired by an entity or spirit outside the universe as you say? And if we can never know of things outside the Universe (i.e. Creation, as you say), then what information do you have that makes you believe that the Bible originated there and not in the minds of men? It is folly to seek the Mind of God at the expense of understanding the Mind of Men, since we live among Men and must interact with them (unless you want to be a hermit). Ethics can only be taken as far as it applies to men. In the early 20th century, a mystic named Aleister Crowley wrote a work called "The Book of the Law," that he claimed was the channeled word of the spirit Aiwass. There have been many other so-called "inspired works." What makes the Bible true and these others false? What criteria do you use for judgement?