Sarah That occurred to me, too! Upon reflection, I came to the conclusion that Sam seems to be an unusually discerning character. Liza, on the other hand, isn't outright described as undiscerning, but she was adamant about reading the Bible, not studying it—not asking questions, not wondering about any perceived conflicts. Liza isn't inquisitive, and seems to accept things as they are, even when perhaps she shouldn't.
Ashley Liza does see evilness in Cathy, not to the same degree as Samuel does, but Liza does recognize it: "I can find no real fault with her save perhaps a touch of laziness, and yet I don't like her very much (197)."
Mary Raihofer Also, Liza saw virtue in a woman who spoke little and kept things to herself and saw gossip in less than a virtuous light. Her husband Sam had that 6th sense - he could feel the chill of evil. And that is what took Sam back a little. He thought Liza could do the same and yet in this case, Liza saw things in black and white.