In this essay I consider how Habermas and Foucault understand the nature of truth and reason in fundamentally different ways, and I argue that Habermas' misunderstanding of Foucault's position on these issues undermines his critique of Foucault. I argue that a strong response to Habermas' criticism is implicit in Foucault's work, and that this implicit response also offers us an occasion for reinterpreting all of Foucault's work as a single, unified project with roots in the Enlightenment.