Remathilis
Legend
In D&D, yes. Good is opposite to evil. That is why the PH refers to the "good/evil" axis.
Good-aligned weapons defeat evil outsider DR
Protection from Evil is a good-aligned spell. (and thus, evil clerics cannot cast it).
Paladins smite evil, blackguards smite good.
holy water is good-aligned, damages evil. Unholy water does the opposite.
Now, for the actions of mortals and outsiders, the line is a bit blurrier.
According to Savage Species, an outsider is "born" with its alignment subtype and requires powerful magic to change that. So a succubus (outsider, chaotic, evil) who dons a helm of opposite alignment becomes LG in alignment, but maintains the (chaotic, evil) subtypes and can still be smote by a paladin, even if she and the paladin are "technically" the same alignment and even might act under a similar moral code.
Mortals even further blur the line. Individual mortal actions can be seen as good or evil, even when they are both, neither, or the opposite. D&D tries to define certain actions as "nearly always" evil: lying, killing innocents, stealing, torture, cannibalism, necromancy, using poison, etc. However, an individual might not precieve any of the abovie as evil, especially if "the end justifies the means" Thus, a good person might lie to a foe to save his family, torture an orc to find thier base, eat a friends corpse to survive in the wilderness, use poison to take down a rampaging dragon, or use necromancy to fight an evil demon hell-bent on distruction. While the action can be justified, it doesn't make it "good".
To your examples:
1.) A celestial infiltrating a fiendish organization would have his morals tested regularly. Even if his motives were pure, the act of doing "evil" things would taint him. He wouldn't remain good (becoming neutral after a while, evil if he continued for a long time), and would probably need to atone.
2.) A fiend in a celestial organization would have a similar but different challenge. He would have to "accept" doing good deeds like saving orphans, stopping wars, or saving lives. If his goal was the toppling of the organization, he'd probably remain evil. However, the fact he'd have to take the high-road to maintain his cover would grind on him, and I can't see a fiend who would do this for long and remain a truly evil being. He also might drift toward a selfish-neutral.
Why the disparity? It seems goodness (and law) in D&D are held as ideals (hence the paladin) and are difficult to attain, but must be stove for. Its easy to embrace an evil to-hell-with-it mindset, but goodness requires determination and sacrifice.
I'll leave this thought with a quote that sums it up.
Good-aligned weapons defeat evil outsider DR
Protection from Evil is a good-aligned spell. (and thus, evil clerics cannot cast it).
Paladins smite evil, blackguards smite good.
holy water is good-aligned, damages evil. Unholy water does the opposite.
Now, for the actions of mortals and outsiders, the line is a bit blurrier.
According to Savage Species, an outsider is "born" with its alignment subtype and requires powerful magic to change that. So a succubus (outsider, chaotic, evil) who dons a helm of opposite alignment becomes LG in alignment, but maintains the (chaotic, evil) subtypes and can still be smote by a paladin, even if she and the paladin are "technically" the same alignment and even might act under a similar moral code.
Mortals even further blur the line. Individual mortal actions can be seen as good or evil, even when they are both, neither, or the opposite. D&D tries to define certain actions as "nearly always" evil: lying, killing innocents, stealing, torture, cannibalism, necromancy, using poison, etc. However, an individual might not precieve any of the abovie as evil, especially if "the end justifies the means" Thus, a good person might lie to a foe to save his family, torture an orc to find thier base, eat a friends corpse to survive in the wilderness, use poison to take down a rampaging dragon, or use necromancy to fight an evil demon hell-bent on distruction. While the action can be justified, it doesn't make it "good".
To your examples:
1.) A celestial infiltrating a fiendish organization would have his morals tested regularly. Even if his motives were pure, the act of doing "evil" things would taint him. He wouldn't remain good (becoming neutral after a while, evil if he continued for a long time), and would probably need to atone.
2.) A fiend in a celestial organization would have a similar but different challenge. He would have to "accept" doing good deeds like saving orphans, stopping wars, or saving lives. If his goal was the toppling of the organization, he'd probably remain evil. However, the fact he'd have to take the high-road to maintain his cover would grind on him, and I can't see a fiend who would do this for long and remain a truly evil being. He also might drift toward a selfish-neutral.
Why the disparity? It seems goodness (and law) in D&D are held as ideals (hence the paladin) and are difficult to attain, but must be stove for. Its easy to embrace an evil to-hell-with-it mindset, but goodness requires determination and sacrifice.
I'll leave this thought with a quote that sums it up.
Yoda said:
