Obeah (called "vodou" or "voodoo" in the French-speaking Caribbean), a folk religion indigenous to the Caribbean, casts a huge shadow over this novel, though whether its magic really works is up for debate. (Read more about obeah here). Obeah seems to inspire fear more through what it's rumored to do rather than through actual feats of magic. The Haitian revolution in 1791 was thought to be initiated by a voodoo ceremony, and obeah practitioners were imprisoned because they were thought to encourage slave insurrections (Rhys 1999: 75). In Wide Sargasso Sea, obeah is often juxtaposed to Christian beliefs and to rational, scientific thought, bringing up questions about how different systems of belief operate.
In the novel, neither obeah nor Christianity are shown to be a superior way of understanding the world; both are shown to be belief systems that require the radical suspension of critical thought on the part of the individual.
The novel demystifies the magic of obeah by showing how it is a culturally specific expression of a community's identity and history.