Symbolism, Imagery, Allegory
Part IV of The Joy Luck Club begins with—you got it—another uber-symbolic parable.
In this parable, a grandmother is snuggling her baby granddaughter and talking to the kiddo about innocence (which is a pretty heavy subject for a little kid, actually). The granddaughter, being a baby, just keeps laughing.
The grandma reflects on this. She thinks back to her own loss of innocence, and the fact that she pushed her daughter to grow up too fast. A lack of innocence, the grandma thinks, means not only being able to recognize darkness in other people, but to nurture darkness within yourself. This is a spooky thought.
Then the grandma has another thought: what if the granddaughter is the reincarnated Queen Mother of the Western Skies who has learned that laughter is the wisest thing of all? This is uplifting, and the grandma resolves to laugh more...and to encourage her daughter to laugh more as well.
The symbolism here is a two-fer. The first possible meaning is that the advice handed down from the older generations to the younger is sometimes...just plain wrong. The second (more optimistic) reading is that the younger generation (yup, even babies) can act as pretty fantastic teachers...if only the older generation is ready and willing to listen up.