The "sea change" is a symbolic transformation that represents a type of resurrection, a death-and renewal of person, in which the subject is resurrected as something new and valuable, something "rich and strange." Zora Neale Hurston writes about her own sea change in "How It Feels to Be Colored Me," and she uses this symbolic transformation as one of the themes of Their Eyes Were Watching God.
In the very beginning of the novel, Hurston describes the differences between the ways that men and women each think about the future. Men wish for things like "ships at a distance." Some of them realize their dreams, and some of them don't, but they all dream. Women, according to Hurston, "forget all those things they don't want to remember, and remember everything they don't want to forget." They force themselves to be content with their situation and romanticize the reality, thereby avoiding disappointment. "The dream is the truth." While there is something practical about contentment, it is natural for women and men both to "dream," to desire something beyond themselves, something that will cause them to grow and improve if they are to attain it.
Janie returns to Eatonville after "burying the dead," the "sodden and bloated." However, it is not only Tea Cake that has been buried, but the former Janie as well. Because of Tea Cake's influence, Janie ceases to be a woman who forces herself to be content with her situation, with her forced marriage to Logan, with her cloistered existence with Joe. As Tea Cake nurtures Janie's ability to dream, to look beyond what is to what she could become, she becomes more like him, transient, open-minded, and happy.
In order to undergo the sea change, however, this death, or symbolic death, must first take place. Like Ferdinand washed onto the shore in The Tempest, Janie has to suffer the death of her former self to become the new creature that returns to Eatonville.