The value of anything is established by its properties. If values aren't really arbitrary, then there is an absolute morality. The rest of this is trying to explain why values can't be arbitrary, they can only be misunderstood as arbitrary.
This thread is an argument that order is the basis of all concepts. Order is very rigid, so when you build a concept like a moral system on it, like all concepts should be built, it is going to lead to absolute results. Morality is based on values, and the only way to justify morality is to prove your values are accurate. My argument is that values aren't arbitrary, thus there is an absolute morality.
Original post below:
Many atheists shy away from absolute morality because it sounds religious. I argue that there has to be an absolute morality because the universe is absolute. This may seem wrong as there are many subjective things. I am contending that this isn't true because subjectivity resides on the conceptual level and like disorder and change is not a part of actual existence, but rather merely descriptive. Absolute morality has to exist because the base foundation for morality is order, which enables it to have structure as a social concept. This means that even as a concept, it has to have an absolute and most perfect form as a social concept.
I have been working on this for a while, and I think I am nearing completion, but I am wondering what faults may be found with this line of thought... I have had to return to the drawing board to correct my errors a few times already.
This below is an addendum:
What I am contending is that once morality is conceived as a concept, the nature of order upon which any concept is structured necessitates a most perfect form.
Individual perception causes humans to see the concept with innaccuracy in contrast to the order with which the concept maintains structure in conceptual reality. This creates subjectivity.
But where I am really going with this is that order is the base functional principle of any structure in the universe.
At the very foundation of the level of actuality lies order. Without order, molecules neither form nor bind. Order enables structure, which in turn enables every other level of existence. Order permeates every level of existence as its foundation, including anything that exists on the conceptual level. For this reason, structural order serves as the archetypal basis that justifies having a moral system.
Disorder is mistaken as coexisting with order, but it exists on the conceptual level only and is a name given to an observation of change. It is not a counterpart to order. That means disorder is not actual. It is conceptual.
These things tie together to start to point out that best action can be established on the basis of the order of the universe, and the lack of actuality of disorder which would be its only challenger.
Humans aren't absolute therefore their morals aren't absolute. I like Dawkins idea of the ever changing moral zeitgeist. We adjust out morals as we evolve... but our evolution isn't in a constant direction towards an absolute state but adjusts to its environment.
Therefore we can only have a human morality based upon our environment.