That's a good angle to take, good or positive versus the bad or negative aspects of a persons will. Each drawing on either light or shadow as a result.
TL:DR bellow....
Taking a slightly different approach, it seems that the popular angle to take on "the light" is that it is a force or energy just like "arcane" or "nature". Like them, the light is therefore a neutral force, neither good nor bad, it just is. Perhaps this is derived from recent interactions with the pandas. I am not sure where this concept originates, but I rather like it. :)
Considering it thus, they then explain that the wielding of "the light" is based solely on one's conviction. Conviction that what they are doing is right, or perhaps ultimately 'good'. Much like a Scarlet Crusade Paladin wields light based power, he does so because he is completely convinced in the righteousness of his actions. So as long as I maintain the conviction that regardless of what I am doing it is for the right reasons (or the greater good) then I can use "the light". I can heal or I can smite.
It was an interesting take for me because (in my view) it completely disassociates "the light" from any sort of dogma or religious stance.
It no longer mattered "how holy" you were, so long as you maintained your conviction in the 'goodness' of your own cause. Seen like this, it made sense to me that someone like, say, oh, a gnome, who is by nature (and mostly tradition) a creature of pure logic doesn't need to find his spiritual side. He doesn't need to trade his cold reasoning logic for something as intangible as warm fuzzy faith. All he has to do is hold a powerful conviction in the righteousness (or goodness) of his cause and he can wield "the light", apart from any established order or faith.
This is the path that I have been slowly leading Cail down. I want him to be able to use the light to heal people, yet he just can't fathom religion. He's a doctor. Helping and healing people is in his bones. Until now he's only been able to use his skill, knowledge, technique, technology, and alchemically derived compounds. So as he is progressing into this notion of "the light" as a tool and a power that he can learn to harness, its opened up curiosities about the use of Shadow. Both for him as a character and more importantly for ME as his creator. :)
So if we say that "the light" is wielded through conviction in a righteous cause, how then is "the shadow" wielded?
I like the concept of a good or at least benign Shadow Priest.
How then is he able to use "shadow" if the power of shadow were related to evil or negativity?
Where dose that shadow come from?
For that matter, where does "the light" come from?
If the light is something that just is, a force like the Arcane or Nature, then could we also say that Shadow just is? Perhaps we can look at it as a parallel to Fel Magic. A force that corrupts and taints.
In my understanding Fel is derived from the Arcane. It's Arcane that has been stripped down to its most basic raw form. Where Arcane is Orderly, Fel is Chaotic. If that is true, then Fel is no more 'evil' than the Arcane is 'good'. If "the light" could be considered a parallel to Arcane, then perhaps "shadow" is simply a stripped down raw version of "the light". It would then neither be good nor evil. It just is.
Did you follow me through that wall of text? :P
If not, that's ok.
TL:DR
If Light is similar to Arcane, and Fel is derived from Arcane, then Shadow is equally derived from Light.
If Conviction is similar to Will, and Light is similar to Arcane, then only a strong Conviction is needed to use Light. Good or Evil never factors into the ability to use said power.
Follow? Make sense? Where am I right and where am I wrong?
Comment people! I need more data! :D
