Identity Quotes in The Curious Incident of the Dog in the Night-Time

How we cite our quotes:

Quote #4

And I don't know what some hardness, perhaps of eye means, and I'm not interested in faces. (107.11)

For most of us, a person's face makes up a big part of his or her identity. (Note: not that person's personality, but his or her identity – for example, when we imagine a person in our minds, we might picture the face first.) If Christopher is uninterested in faces, then what are the important factors in identifying a person?

Quote #5

And it was strange because he was calling, "Christopher...? Christopher...?" and I could see my name written out as he was saying it. [...] I could see it written really large, like it was on a big advert on the side of a bus. And it was in my mother's handwriting [...] (157.26)

This is a powerful image, evoking just how earth-shattering the discovery of his mother's letters must be. It has even dislodged his sense of self, so that he sees his own identity as being wrapped up in his mother's idea of him in her letters.

Quote #6

But the mind is just a complicated machine. (163.10)

Is this is all what the mind is – a complicated machine? Or does he really mean the brain? Either way, do you agree?