ABSTRACT As the most famous critic of John Stuart Mill, James Fitzjames Stephen has often been assumed to have been a religious conservative or even reactionary. In contrast to these assessments, this article shows that Stephen's most consistent enemies were what he took to be the two most significant religious forces of the modern world: Ultramontane Catholicism and Comtean Positivism. The article explores his objections to these two religious ideologies, which he saw as sharing certain harmful features. It then shows (...) that his famous critiques of John Stuart Mill and liberalism had much in common with his attacks on Ultramontanism and Positivism; for example, he charged that they rested on an implausible philosophical anthropology and that they degraded the state. (shrink)