I argue that Irigaray's recent work develops a theoretically cogent and politically radical form of realist essentialism. I suggest that she identifies sexual difference with a fundamental difference between the rhythms of percipient fluids constituting women's and men's bodies, supporting this with a philosophy of nature that she justifies phenomenologically and ethically. I explore the politics Irigaray derives from this philosophy, which affirms the sexes' rights to realize the possibilities of their rhythmically diverse bodies.