Jeanne Damoff writes about Lewis’ gift for telling the truth in fiction:

Lewis does a great job of portraying the woman as intelligent but entirely pure. She entertains the Un-man’s ideas because she’s never had a reason not to listen to anything being said to her. Though Ransom tries to counter all the lies, the woman has no reason to trust one of them over the other. She’s never encountered debate, never required discernment. But occasionally the Un-man pushes too far. When he invites her to “make a story” about living on the Fixed Island–to imagine herself doing the forbidden thing–she says, “If I try to make a story about living on the Fixed Island, I do not know how to make it about Maleldil. For if I make it that He has changed His command, that will not do. And if I make it that we are living there against His command, that is like making the sky all black and the water so that we cannot drink it and the air so that we cannot breathe it. But also, I do not see what is the pleasure of trying to make these things.”

She follows up this post with another called “The post I do not want to write.”