Immanuel Kant shook the foundations of Western philosophy in the late eighteenth and early nineteenth centuries. This author and professor did his most important writing between 1781 and 1790 while working at the University of Königsberg, where he spent most of his life. Kant's philosophical model not only swept aside the ideas of the so-called empiricists and rationalists who came before him, it also had a lasting effect outside of philosophy, especially in the areas of ethics and the law. Today, legal scholars still debate his ideas?and their sometimes startling implications?in relation to contemporary issues.
Kant was born into a lower-middle-class family in East Prussia in 1724. A gifted student, he studied in a Latin school from age eight until age sixteen, when he entered the University of Königsberg to take up theology, natural science, and philosophy. The death of his father forced
him to abandon his studies in order to work as a private tutor, and he had to wait several years before returning to complete his education. By that time he was already writing serious books. From what is called Kant's precritical period, these early works are primarily scientific. In recognition of his talents, the university made him a lecturer and eventually a professor. He taught logic and metaphysics.
Twenty years later Kant attacked the reigning schools of thought. In this so-called critical period, he wrote his most famous book, The Critique of Pure Reason (1781). Kant's work examined the relation of experience and perception: he was concerned with how people know what they know, and just as important, the proper uses of the powers of reasoning. He argued that reality can be perceived only to the extent that it complies with the aptitude of the mind that is doing the perceiving. This places one kind of
limitation on what can be known. Kant saw another limitation, too: only phenomena?things that can be experienced?are capable of being understood; everything else is unknown. The human senses, therefore, take supreme precedence in determining what is real.
These theories have implications for conventional morality. Kant viewed God, freedom, and immortality as incomprehensible: they can only be contemplated; their existence can never be proved. Nonetheless, he argued, all three of them are important as the basis for morality. Kant believed...