The Prussian philosopher who attempted to reconcile rationalism and empiricism, established the Categorical Imperative as the foundation of moral philosophy, argued for the conditions of possible experience in the Critique of Pure Reason, and shaped every major philosophical tradition that followed — from German idealism to analytic philosophy to contemporary ethics.
Kant said that Hume woke him from his 'dogmatic slumber.' He then spent eleven years writing nothing, and produced the Critique of Pure Reason — one of the most difficult and consequential books in the history of philosophy. He also invented the Categorical Imperative: act only according to the principle by which you could will that everyone act. The moral rule that underlies modern human rights law came from a bachelor in Königsberg who never traveled more than a hundred miles from home.