The Prolegomena to any Future Metaphysics That Will Be Able To Present Itself as a Science was written by Immanuel Kant in 1783. Kant was one of the greatest philosophers of the German Enlightenment. He worked to synthesize the two main philosophical traditions of his time, rationalism and empiricism, and to overcome the deadlock between them. The Prolegomena is an attempt to clarify for a general readership the central arguments of his magnum opus, The Critique of Pure Reason, which had been published two years before, in 1781. As a shorter and more accessible work, it is perhaps the best introduction to Kant's philosophy.
In the Prolegomena, as in the Critique, Kant attempts to answer the question, “what can we know?” He asks why, unlike mathematics or the natural sciences, philosophy has failed to produce any universally-accepted truths, and attempts to place it on the same scientific basis as these disciplines. Kant does so by attempting to answer the question of whether, and if so under what circumstances, the human mind is able to make what he refers to as “synthetic judgments a priori.” What this means is judgments that teach us something we didn't know (synthetic) but do not rely on sensory experience to learn it (a priori). In Kant’s view, if metaphysics—Kant’s name for philosophy—can answer this question, then it can finally establish itself as scientifically legitimate. Initially read more widely than the Critique, the Prolegomena drew widespread attention to Kant’s work, and became one of the foundational texts of the German Enlightenment.
Kant’s Prolegomena set the stage for a philosophical revolution in Germany at the end of the eighteenth century that would spread to the rest of Europe in the twentieth. By turning philosophy away from the solving of questions and into an exploration of the functioning and potential of the human mind, Kant’s work directly influenced philosophers like Fichte, Hegel and Schelling, as well as later philosophers like Gottlob Frege, Edmund Husserl, and Martin Heidegger. His understanding of philosophy as a fundamentally “critical” task, whose purpose was to test ideas and determine their legitimacy, would in turn influence the critical philosophies of Karl Marx and Friedrich Nietzsche.