At the beginning of the book, Meg is unhappy because she doesn't fit in at school, and desperately wishes she could be the same as everyone else. She's smarter than most kids, but her unorthodox way of thinking is not understood by her school, and she reacts by being sulky and stubborn. Her five-year-old brother, Charles Wallace, is also made fun of for being abnormally intelligent and different. But then the two meet Calvin, a "cool" kid who is unhappy because he hides his differences, and the Mrs. W's, who are the weirdest and most wonderful people they have ever met, and Meg begins to reconsider the value of her "differences".
The final nail in the coffin of Meg's desires for sameness come when the children visit the planet Camazotz, which has been entirely taken over by the Black Thing. On Camazotz, everyone is the same, everyone conforms to the standards set by IT, and it is the unhappiest place in the book. When Charles Wallace gets assimilated IT and becomes the same as everyone on Camazotz, Meg realizes just how much she doesn't want herself or anyone she loves to have their differences taken away.
The novel also contains many quotes from and references to great writers, thinkers, and scientists of the past (Shakespeare, Einstein, Goethe, etc.), all of whom were very "different" but accomplished great things for the good and the light through their work, and who are presented as the Earth's greatest fighter's against the Black Thing. In other words, the novel presents difference as not just a fact of life, but as a vital thing, the most important thing in the fight against evil.
Nonconformity Quotes in A Wrinkle in Time
How did Charles Wallace always know about her? How could he always tell? He never knew—or seemed to care—what Dennys or Sandy were thinking. It was his mother's mind, and Meg's that he probed with frightening accuracy.
"…I'm a sport."
At that Charles Wallace grinned widely. "So ‘m I."
"I don't mean like in baseball," Calvin said.
"Neither do I."
"I mean like in biology," Calvin said suspiciously.
"A change in gene," Charles Wallace quoted, "resulting in the appearance in the offspring of a character which is not present in the parents but which is potentially transmissible to the its offspring."
"But you're good at basketball and things," Meg protested. "You're good in school. Everybody likes you."
"For all the most unimportant reasons," Calvin said. "There hasn't been anybody, anybody in the world I could talk to. Sure, I can function on the same level as everybody else, I can hold myself down, but it isn't me."
"But Charles Wallace doesn't look different from anybody else."
"No, Meg, but people are more than just the way they look. Charles Wallace's difference isn't physical. It's in essence."
"We are the most oriented city on the planet. There has been no trouble of any kind for centuries. All Camazotz knows our record. That is why we are the capital city of Camazotz. That is why CENTRAL Central Intelligence is located here. That is why IT makes ITs home here." There was something about the way he said "IT" that made a shiver run up and down Meg's spine.
"For why should you wish to fight someone who is here only to save you pain and trouble? For you, as well as for the rest of all the happy, useful people on this planet, I, in my own strength, am willing to assume all the pain, all the responsibility, all the burdens of thought and decision."
"I'm different, and I like being different." Calvin's voice was unnaturally loud.
"Maybe I don't like being different," Meg said, "but I don't want to be like everybody else, either."
"Nobody suffers here," Charles intoned. "Nobody is ever unhappy."
"But nobody's ever happy, either," Meg said earnestly. "Maybe if you aren't unhappy sometimes you don't know how to be happy."
"But that's exactly what we have on Camazotz. Complete equality. Everybody exactly alike."
For a moment her brain reeled with confusion. Then came a moment of blazing truth. "No!" she cried triumphantly. "Like and equal are not the same thing at all!"
"You don't even know where we are!" she cried out at her father. "We'll never see Mother or the twins again! We don't know where earth is!...What are you going to do!" She did not realize that she was as much in the power of the Black Thing as Charles Wallace.
"You mean you're comparing our lives to a sonnet? A strict form, but freedom within it?"
"Yes." Mrs. Whatsit said. "You're given the form, but you have to write the sonnet yourself. What you say is completely up to you."