Anthropomorphism is a motif in the book. Dorothy's first major experience with an inanimate object coming to life happens in Chapter 3, when she meets the Scarecrow:
While Dorothy was looking earnestly into the queer, painted face of the Scarecrow, she was surprised to see one of the eyes slowly wink at her. She thought she must have been mistaken at first, for none of the scarecrows in Kansas ever wink; but presently the figure nodded its head to her in a friendly way.
Dorothy is startled to see the Scarecrow wink and nod at her, but she takes the new development in stride. Her ability to look into the Scarecrow's face and recognize the friendliness and humanity there emphasizes the way her childishness makes her well-suited to the journey through Oz. An adult may doubt their own eyes if they saw a scarecrow wink, but Dorothy is confident in what she sees because, as a child, she believes the world holds all kinds of strange and whimsical possibilities. The fact that Dorothy is familiar with scarecrows from her life in Kansas suggests that Oz could be a creation or reflection of her own imagination. Whether or not Oz is a real place, Dorothy seems to fit in there. She is able to make friends with all kinds of anthropomorphized creatures along the way—more friends than she ever made in dusty Kansas with tired Aunt Em and Uncle Henry. Her laughter and bubbly personality, which have always seemed out to place to Aunt Em in Kansas, make more sense in this whimsical place.
And yet there seems to be a difference between fitting in and belonging. Dorothy spends her time in Oz longing for "home," which for her is the grayer world where she lives with her aunt and uncle. Each of the anthropomorphized characters has a home in Oz, whether that is in the Emerald City or the "Dainty China Country." Dorothy knows that for her, these are all places of childish fancy. Toto, arguably Dorothy's best friend, is the one animal who is never anthropomorphized. He remains by Dorothy's side the whole time, anchoring her to the "real" world where dogs cannot speak in human language.
Baum plays with language and children's tendency to take it literally. For example, in Chapter 20, he uses anthropomorphism to play with the meaning of an idiom:
‘Be quiet, sir!’ said the Princess; ‘can’t you see these are strangers, and should be treated with respect?'
‘Well, that’s respect, I expect,’ declared the Clown, and immediately stood upon his head.
‘Don’t mind Mr Joker,’ said the Princess to Dorothy; ‘he is considerably cracked in his head, and that makes him foolish.’
Dorothy and her friends are in the "China Country," where all of the inhabitants are anthropomorphized china. The Princess tells Dorothy that the Clown is "cracked in his head," which is typically an unkind idiom meaning mentally ill. Because the Clown is literally a piece of china with cracks in his head from trying to stand on it, Baum is able to call attention to the strange difference between the idiom's literal meaning and its figurative meaning. A child might be more likely to hear that someone is "cracked in his head" and think of an image like the Clown, rather than an image of a mentally ill person. Even the idea of the "Dainty China Country" draws on children's tendency to interpret language literally. In 1900, "China Country" might refer to China itself or to Chinese communities within Western countries. Baum imagines that to a child, adults' references to "China Country" might conjure the image of a country where everyone is made out of china.
Baum is not necessarily making a grand political statement by playing with these idioms. Instead, he is having fun with the way a child's imagination is unbound by reality and conventional ways of speaking and thinking. Aunt Em is often struck by how Dorothy can remain so cheerful on the dusty plains of Kansas. Playful moments like this suggest that it is Dorothy's young imagination that sets her free from the confines of the difficult life that has worn on Aunt Em for so many years. And in the end, Dorothy is able to go back home to Kansas with the colorful world of Oz in her mind as a permanent escape. This emphasis on youthful imagination sends the message that adults would do well to have a more childish outlook on life.
