Immanuel Kant (1724-1804) was a German philosopher whose influential work in epistemology, metaphysics, ethics, and aesthetics shaped the course of modern philosophy. Central to his thought was the notion of the "categorical imperative," a principle that requires individuals to act in a way that their actions could be universally applied as a moral law. In his critical philosophy, Kant sought to reconcile empiricism and rationalism, arguing that human knowledge relies on both sensory experience and innate structures of the mind.