Negative Zero asks
if Darkness is simply the absence of Light (failed ABC show Miracles notwithstanding) is Chaos the absence of Order? or is it the other way around?
Well, there are two related questions here:
(a) what kind of world do you want to create?
(b) based on the mechanics of D&D regarding Law and Chaos, what must necessarily be true about the Law-Chaos dynamic in your world?
Of course, question (a) can be answered almost any way. However, there are a few obvious possibilities:
1. Order is the natural state in which the universe existed before time and chaos was somehow unleashed into the universe as a cancerous force eating away at it. (In this theory, chaos has a good analog with entropy -- time exists because we can measure the escalation of this thing: chaos/entropy which is unidirectional.)
2. Chaos is the natural state in which the universe existed before time and order was somehow imposed by a freak organization of matter within the chaos, creating some kind of order-bestowing entity/God. Gradually, order is overcoming chaos, beating it back even if it loses battles to chaos from time to time.
3. Nothingness is the natural state in which the universe existed before time but with the introduction of matter, two opposing forces came into existence: one which sought to order, consolidate and organize matter, the other seeking to disperse matter.
4. Chaos and Law are forces which have always existed since the beginning; the two are evenly matched and vie against eachother eternally.
I would argue that arguing that chaos is the mere absence of order is actually #2. Chaos, there, is not so much an active principle as it is the inherent state of things that have not been given purpose and form by law/order.
In response to (b), I would argue that option #2 in which chaos is not an active principle is problematic. As long as D&D recognizes "neutral" as a concept, neither evil nor chaos can simply be defined as an absence of good or law; the mere absence of such things, I would argue, is represented by neutrality. Thus, in my reading of the D&D game mechanics, chaos and evil must be active principles; so, throw away your Catholic theology (in which evil is the mere absence of good) -- as far as D&D is concerned, chaos and evil are active principles.
My theory of evil and chaos as active principles is also somewhat supported by the mechanics of detection spells. People can detect law, chaos, good and evil but they cannot detect neutrality. Furthermore, in the description of
detect chaos, chaos is described as having a "strength" -- this cannot work for the absence of law/order concept.
If neutrality were a simple balance or synthesis of law and chaos, one would expect that neutral people would register in both a
detect law and a
detect chaos spell but instead, the neutral register with neither spell. This suggests to me that neutrality is the absence-defined thing, not chaos.