According to Book of Exalted Deeds, how to choose between two evils?

Question

The Book of Exalted Deeds says that evil means used to prevent greater evil cannot be used by good characters, and says:

Some good characters might view a situation where an evil act is required to avert a catastrophic evil as a form of martyrdom: "I can save a thousand innocent lives by sacrificing my purity." [...] After all, it would simply be selfish to let innocents die so a character can hang on to her exalted feats. Unfortunately, this view is ultimately misguided. [...] What the character sees as a personal sacrifice is actually a shift in the universal balance of power between good and evil, in evil's favor, thus it is not a personal sacrifice, but a concession to evil, and thus unconscionable.

And

Good ends might sometimes demand evil means. The means remain evil, however, and so characters who are serious about their good alignment cannot resort to them, no matter how great the need.

However, standing by while a catastrophic evil happens, while doing either nothing or attempting a good scheme with very little chance of success, seems to be evil as well.

There is guidance in the book that exalted campaigns shouldn't force PCs to choose between two evils, but what are the characters supposed to do if it happens anyway? Or, what are non-player good characters supposed to in those situations?

Despite all of that text, it still seems that the least evil thing to do would be to actually perform the evil act. Is that the right interpretation?

Answer 1

This answer comes with caveats:

• Your literal question of "Which interpretation is right" is going to depend on who you're asking and what side of the fourth wall they're on. Alignment questions are difficult to properly answer here if they require us to apply real-world judgment, which the vast majority of them do. I'm going to assume that the adjudication of the individual acts as good or evil is an issue settled elsewhere and focus strictly on what happens when such acts are compared and combined as stated in the question.
• The source you've cited, the Book of Exalted Deeds, is one of the most controversial pieces of the ruleset. In this answer, I'm going to assume everybody - players, GM, even audience if any - understands this and accepts it as part of this game without question. Whether this assumption is justified is, again, best debated elsewhere.

With all that out of the way...

The Book of Exalted Deeds, as you've cited, explicitly makes it clear that the idea of good ends justifying evil means simply doesn't work that way, and that less evil ends justifying more evil means simply isn't a meaningful question. These acts remain evil despite the given reasoning and will affect a character's alignment accordingly.