Kant’s 'critical philosophy' revolutionized Western thought by synthesizing rationalism and empiricism. In his Critique of Pure Reason, he argued that human understanding is the source of the general laws of nature that structure our experience. His moral philosophy, centered on the 'categorical imperative,' emphasized duty and the inherent dignity of the rational individual. Kant lived his entire life in Königsberg, Prussia, where his disciplined habits were legendary. His work on ethics, metaphysics, and aesthetics remains the fundamental starting point for almost all subsequent philosophical inquiry.