In Timaeus, Plato's third kind introduces an ambiguous borderland space that is neither of the categories that it separates and unites, but somehow partakes of both. In the cosmology of the Timaeus, Plato uses the model of the family as the foundation for his description of the cosmos' birth; he consistently identifies the male as active and the female as passive, grounding these binary categories in such a way that renders only male subjects as autonomous beings. Using the models of sexual reproduction in Octavia Butler's Wild Seed and her Xenogenesis series, Decker argues that the third kind disrupts the binary models of sexual difference that Plato's dualistic system attempts to ground.