This paper focuses on the cancan as a primary site for the nineteenth-century struggle between Enlightenment rationalism and its ‘other’, the supposedly irrational and elusive body. Rationalism strove to separate the lower orders of the body from the higher orders of the mind. This position was given scientific justification by social evolutionary theory, which posited biological differences between those dominated by the lower orders, the working class, the culturally other, and the female, and those dominated by the higher orders, the upper class, white Europeans, and the male. In the 1830s, the cancan emerged in Paris as a dance practice which both reinforced and subverted social evolutionary theory. In doing so, it not only questioned the relationship between artistic practice and scientific theory, but challenged the separation of rationality and irrationality on which the notion of theory was, and continues to be, based.