People want to feel safe. As they grow up, they learn how to deal with others, navigate their social worlds, and learn how to negotiate with those whose desires conflict with theirs. Christopher needs all of this, too, but he struggles to communicate, which places him at a disadvantage with others and puts him in danger when he goes out alone. Christopher is aware of this, and he finds safety, not in other people, but in his own mind.

First, he has strict rules about how to deal with the world. He plans his day to the minute; he eats specific foods in specific ways; he speaks rote phrases to social questions; he rates days as good or bad depending on how many red or yellow cars in a row he sees from the school bus window. These techniques may seem stiff and arbitrary to outsiders, but to Christopher they represent stability in a chaotic world.

Second, he fills his thoughts with math and science. Christopher does this partly because he loves the power and certainty of mathematical and scientific proofs, and partly for their soothing effect on his often-anxious mind. On his journey to London, he must wend his way through crowds of people whose overwhelming presence terrifies him; to soothe his anxiety, he performs difficult arithmetical exercises in his head, which keeps his mind occupied and less frantic.