In thinking about this, I'd like to suggest that the problem of consistency isn't just a problem for Christianity. As I've pointed out before, evil is a problem for materialists as well. For example, we could set out a materialist version of the trilemma:
1. The material universe is all that exists.
2. Any material configuration of the universe is neither good or bad, right or wrong.
3. Evil exists.
#1 is just the metaphysical commitment of materialism. So there shouldn't be much debate there. Any pushback would come with #2 and #3 and their relationship.
Specifically, by #3--"Evil exists"--we mean the claim that something is "wrong" with the material universe. And by "wrong" we mean something more than "wishing it were otherwise." "Evil" is a stronger, moral claim that goes beyond our preferences and wishes. To say that evil exists is saying something more than that I prefer or wish the universe were otherwise. To be sure, we do wish the universe were otherwise, but that doesn't make the universe "evil."
Why? Because of #2. The material arrangements of the universe are simply what they are, neither good or bad, right or wrong.
Now, the way the materialist threads this trilemma is to redefine what we mean by "evil." Specifically, "evil" just means "great pain." And it's true that material arrangements of the universe cause us great pain, that we experience life as an "evil." In that sense, we can reject #2 as false. Specifically, the current material configuration of the universe can be called "bad" because it is causing us great pain.
And it's here where we'd start to settle into a good debate. Is pain the same as evil? How can pain be "bad"? And even if great pain is "bad," in that I wish life were otherwise, is it wrong that the universe is the way it is, since the universe can't be anything other than what it is? And so on.
Now, to be very, very clear. I'm not saying a materialist can't find a way to harmonize this trilemma. But I am suggesting that such a harmonization would involve adjusting meanings of words like "bad," "wrong," and "evil." Not unlike how Christians rethink a words like "power," "love," or "evil" in their own trilemma.
The point I'm making is this. If we say "evil exists" both the theist and the materialist have a problem on their hands. For both the theist and the materialist evil creates challenges of logical consistency. True, many, from both camps, think those challenges can be met, while others think the tradeoffs required to achieve that consistency gives too much away.
