It was said at the time that philosophers after Kant could agree or disagree with the critical philosophy, but no one could ignore it. One could say a similar thing about German Idealism as a whole. The movement had been so dominant and so influential that nearly every philosopher working in the second half of the nineteenth and early twentieth centuries found it necessary to engage it in some way. The two most important and still-active traditions in Western philosophy, analytic philosophy and phenomenology, began in many ways as responses to idealism. Bertrand Russell, the founder of analytic philosophy, developed his realism and empiricist methodology as an alternative to the idealism that was widespread in Britain at the time, rejecting the legacy of Kant and Hegel. Martin Heidegger, the most important philosopher in the continental tradition, devoted year-long lecture courses to Kant, Hölderlin, Schelling, and Hegel,¹ and he adopted some of their key insights while rejecting their lapses into metaphysics. Hardly any philosophical movement that succeeded German Idealism has been completely untouched by it, either directly or indirectly. Accordingly, this brief survey of the aftermath of German Idealism will proceed in broad strokes.