Immanuel Kant, 1 considered the founder of modern philosophy, was born in Königsberg, East Prussia, (which today is Kaliningrad in Russia) on April 22, 1724. He came from a Protestant family of Pietists. Kant attended the University of Königsberg and became an instructor at the university. For fifteen years he lectured and wrote on various topics in metaphysics, logic, natural sciences: physics, astronomy, geology, meteorology. In 1770 he became a university professor of logic and metaphysics. In 1781 he published his important work, Critique of Pure Reason, which was a starting point for a new field of studies and extensive writing. Second edition which contains many revisions was published in 1787. His reaction to critique to his first edition is found in Prolegomena to Any Future Metaphysics (1783). Both these works represent his transcendental idealism (also termed "formal" or "critical"). This doctrine maintains that our theoretical knowledge is limited to systematization of spatiotemporal appearance.