“No, Meg. Don’t hope it was a dream. I don’t understand it any more than you do, but one thing I’ve learned is that you don’t have to understand things for them to be. I’m sorry I showed you I was upset. Your father and I used to have a joke about tesseract.”

These lines, spoken by Meg’s mother, challenge the common idea that belief and understanding are the same thing. Mrs. Murry references Mrs. Whatsit’s odd visit the night before, telling Meg that the strange woman is real, even if she doesn’t make sense. This paragraph also plants the seed for Meg to discover her parents aren’t infallible. Meg’s father cannot and does not fix everything once he is found, and Meg learns how serious the tesseract is. It is not, as her mother says, a joke, which means Meg’s mother isn’t being completely truthful with Meg here.

“Mr. Jenkins, you’ve met my mother, haven’t you? You can’t accuse her of not facing facts, can you? She’s a scientist. She has doctors’ degrees in both biology and bacteriology. Her business is facts. When she tells me that my father isn’t coming home, I’ll believe it. As long as she says Father is coming home, then I’ll believe that.”

Meg is still a child here. She believes what her mother says because she believes her mother, as an adult and a scientist, is all-knowing. Meg believes this so much that she tells anyone who doubts exactly how she feels. This passage also shows how Meg is more capable and confident than she realizes. Meg spends much of the book believing she is helpless and stupid, but her ability to stand up to her principal (an adult with authority) shows she isn’t as afraid as she thinks.