The Enlightenment or ‘Age of Reason’ witnessed the rebirth of a radical new form of skepticism that started with Descartes. In this course, the ramifications of this skepticism are traced through the early atheism of Rousseau and agnosticism of Hume up to the crucial faith-reason divide of Kant. The subsequent post-Kantian explosion of atheism in both continental philosophy (Nietzsche, Heidegger, Foucault, Derrida) and analytical philosophy (Russell, Flew, Dennett) will be explored, concluding with some responses by contemporary Christian philosophers.