Symbolism, Imagery, Allegory
We've all had comfort objects—no shame in the security blankie game—and, if you're like us, then whatever you found most precious probably got pretty freaking dirty and worn out. Well, until your mom came along and forced it into the wash, anyway.
But what happens when you're older, and your comfort object is a piece of clothing that you take to wearing in very public situations where its presence is socially unacceptable? That's what Miracle has to figure out when she starts wearing her dad's ratty bathrobe everywhere she goes. And we do mean everywhere.
At first, after he disappears, Dane's robe is "a soft coat of armor protecting me, wrapping me in its warm smells of cigarettes, wine, and musty old books—Dane's smell" (2.61). After two years of constantly wearing it, though, "It had become faded and torn […] and I had spilled all kinds of food on it—grape juice, spaghetti sauce, and chocolate—and it smelled of incense" (6.37). Kids tease Miracle about it constantly, saying that they know she doesn't have any clothes on under it.
You'd think that the teasing, let alone the smell, would be enough to convince her to stop wearing the robe, but that's not the case. For Miracle, the robe gives her an identity that she doesn't have without Dane present in her life: "Anytime I removed it, I felt certain that I had become invisible, as if the robe gave my body its shape and substance. Without it I was nothing at all" (7.4). In other words, she doesn't know who she is without her dad, so to hold herself together, she wears his ratty old robe.
Importantly, the robe—like the knowledge of Dane's disappearance and her own lack of identity—weighs Miracle down, making it hard to dance, ride her bike, or do anything that will help her become her own person. She even finds it after the tornado and puts it on, even though it's waterlogged and muddy.
The robe, therefore, is a symbol of Miracle's need to cling to other people to form her identity, especially her dad. It isn't until her treatment at The Cedars and her time with Dr. DeAngelis that she's able to discover that she has a personality separate from her family that makes her unique on her own. So long as she's covered in the robe, we know she's covering herself up with the identities of others.