Germany: Portrait of Immanuel Kant (22 April 1724 - 12 February 1804), German philosopher and writer. Oil painting by Gottlieb Doebler (c. 1762 - 1810), 1791. Immanuel Kant was a German philosopher considered by many as a vital figure in the development of modern philosophy. Kant argued that the human mind forms the structure of human experience, and that reason was the source of morality, among many other ideas. He was one of the earliest exponents of the belief that perpetual peace could be achieved through universal democracy and international cooperation.