AbstractThomas Hobbes sought a reconstruction of philosophy, ethics, and politics that would end, once and for all, the bitter disputes that led to the English Civil War. This reconstruction begins with the first principles of matter and motion and extends to a unique account of consent and political obligation. Hobbes intended to produce a unified philosophical system linking his materialist account of human nature to his moral and political theory. However, his materialism gives rise to a set of perceptions, imagination, and desires that contribute to the chaos of the state of nature. The sort of person that emerges from Hobbes's materialist anthropology is unlikely to be able to make the necessary agreements about common meaning and language that constitute the ground of the social contract. Therefore, Hobbes's materialism frustrates the very purpose for which it is conceived.