Twenty-first-century philosophy has been drawn into a false opposition between speculation and critique. Nathan Brown shows that the key to overcoming this antinomy is a re-engagement with the relation between rationalism and empiricism. If Kant's transcendental philosophy attempted to displace the opposing priorities of those orientations, any speculative critique of Kant will have to re-open and consider anew the conflict and complementarity of reason and experience. Rationalist Empiricism shows that the capacity of reason and experience to extend and yet delimit each other has always been at the core of philosophy and science. Coordinating their discrepant powers, Brown argues, is what enables speculation to move forward in concert with critique. Sweeping across ancient, modern, and contemporary philosophy, as well as political theory, science, and art, Brown engages with such major thinkers as Plato, Descartes, Hume, Hegel, Marx, Heidegger, Bachelard, Althusser, Badiou, and Meillassoux. He also shows how the concepts he develops illuminate recent projects in the science of measurement and experimental digital photography. With conceptual originality and argumentative precision, Rationalist Empiricism reconfigures the history and the future of philosophy, politics, and aesthetics.